United States
Environmental Protection
                 Office of Pesticide Programs
                 Field Operations Division
                 Washington, D.C. 20460
August 1989
                             Printed on Recycled Paper


           Anne R. Leslie
           Robert L. Metcalf

The  opinions, findings, conclusions  and
recommendations expressed herein are those of
the authors and speakers and do not necessarily
reflect the opinions of the U.S. Environmental
Protection Agency.

                        TABLE OF CONTENTS
Introduction	v
      Anne R. Leslie

Section I   Problems Encountered in Controlling Pests with
            Chemical Toxicants
1.   Insect Resistance to Insecticides	3
      Robert L. Metcalf

2.   Ecological Side Effects of Pesticide and Fertilizer Use on Turfgrass	33
      Daniel A. Potter, Stephen D. Cockfield and Terry Arnold Morris

3.   Current and Future Regulatory Concerns for Lawn Care Operators	45
      James F. Wilkinson

4.   Societal Problems Associated with Pesticide Use in the Urban Sector	51
      Anne R. Leslie

Section II   Benefits of an Integrated Pest Management Approach to Turfgrass
             and Ornamentals
5.   Urban Integrated Pest Management Education and Implementation:  Implications
    for the Future	57
      William Brown, Jr., W. Cranshaw and C. Rasmussen-Dykes
6.   Educational, Environmental and Economic Impacts of Integrated Pest
    Management Programs for Landscape Plants	77
      Michael J. Raupp, Mildred F. Smith and John A. Davidson
7.   Integrated Pest Management In the Golf Course Industry:  A Case Study and
    Some General Considerations	85
      Zachary Grant
8.   Societal Benefits of Conservation Oriented Management of TUrfgrass In
    Home Lawns	93
      Anne R. Leslie and William Knoop
9.   Lawn Service Industry:  Transition in Services	97
      Roger Funk

Section III    Current Research Towards Understanding the Pest and the Site
10.  Detection and Monitoring of lurfgrass Pathogens by Immunoassay	109
      S.A. Miller, G.D. Grothaus, F.P. Peterson, J.H. Rittenburg, K.A. Plumley, and R.K. Lankow
11.  Biological Management of TUrfgrass Pests and the Use of Prediction Models
    for More Accurate Pesticide Applications	121
      J.M. Vargas, Jr., D. Roberts, T.K. Danneberger, M. Otto and R. Detweiler

12.   Managing the Scarab Grub Pest Complex In Turfgrass:  Some Ecological
     Considerations  .................................... •• 127
      Michael Villani and RJ. Wright

13.   Influence of Fertilization and Irrigation Practices on Waterborne Nitrogen Losses
     from lurfgrass ...................................... 143
      A.J. Gold, W.M. Sullivan, and R.J. Hull
14.   Surface Runoff from Turf ................................
      M.S. Welterlen, C.M. Gross, J.S. Angle and R.L Hill

15.   The Influence of TURFtech Seeding on Soil Compaction In Southeast Iowa
     and a Mldsouth Region ................................. 161
      Jim  Schaefer and Larry Larson

Section IV     State of the Art Research on Control of lurfgrass Pests Through
               Use of Naturally Occurring Endophytic Fungi

1 6.   The Role of Endophytic Fungi in Grasses:  New Approaches to Biological
     Control of Pests ..................................... 169
      Malcolm R. Siegel, Douglas L Dahlman and Lowell P. Bush

17.   Utilization of Fungal Endophytes of Grasses:  Laboratory Manipulations for
     Specific Toxins ...................................... 187
      Charles Bacon

18.   The Role of Endophytes In Enhancing the Performance of Grasses
     Used for  Conservation and Turf ............................ 203
      C. R. Funk, B. B. Clarke, and J. M. Johnson-Cicalese
Section V    State of the Art Research on Use of Entomophilic Nematodes for
              Control of Turfgrass Insects

19.  Field Effectiveness of Entomophilic Nematodes Neoaplectana and
     Heterorhabditls	215
      Ramon Georgis and George Poinar, Jr.

20.  Entomogenous Nematodes for Control of lurfgrass Insects With Notes
     on Other Biological Control Agents	       227
      David J. Shetlar

21.  Biological Control  of Social Insects with Nematodes	       257
      George O. Poinar, Jr. and Ramon Georgis

Section VI    Manual of Current Practices for Control of Turfgrass Diseases,
              Insects and Poa Annua

22.  Symptomatology and Management of Common lurfgrass Diseases In
    Transition Zone and Northern Regions	273
      Peter H. Dernoeden

23.  Suppression of White Grubs with Microorganisms and Attractants	 297
      Michael Klein

24.  Annual Bluegrass to Bentgrass Conversion with Turf Growth Retardants	307
      Milton E. Kageyama and Larry R. Widell

Section VH    Evaluation of the Site/Pest Complex:  A Starting Point for
               Development of an Urban Pest Management System for

25.  Development of an IPM Program for Turfgrass	315
      Anne R. Leslie

26.  Knowledge Based Systems for Use in Integrated Pest Management:
    Requirements, Pitfalls, and Opportunities	319
      Jan P. Nyrop, Bernie Huber and Walter Wolf


                                     Anne R. Leslie
                         U.S. Environmental Protection Agency
                              Office of Pesticide Programs
                           Field Operations Division (H7506C)
                                   401  M Street SW
                                 Washington, DC 20460
     This book is the product of a symposium held during the 194th American Chemical Society
meetings  in  New  Orleans, Louisiana,  in  September  1987.  Entitled  "Urban Integrated Pest
Management: An  Environmental Mandate", the symposium was  sponsored by the  Division  of
Environmental Chemistry and  co-listed by the Division of Chemical Health and Safety.  The
symposium was a project of the Integrated Pest Management Unit  (IPM Unit) of the United States
Environmental Protection Agency (EPA) to pull together the latest information on alternative controls
for urban pests. An important part of the IPM Unit's mission within the Office of Pesticide Programs
(OPP) has been development of demonstration projects and workshops for technology transfer to
private sector managers. Most of the non-chemical alternatives presented addressed turfgrass and
ornamentals, so this work focuses on turfgrass sites and includes relevant information on integrated
pest management for ornamentals.

     Concerns related to the current pesticide practices for turfgrass include:

     •  increasing problems with resistance to pesticides, which have been documented for
       insects, weeds and fungus diseases,

     •  attitudes of the general public about  health  effects to occupants when pesticides are
       applied to home lawns,

     •  downstream effects based on the appearance of pesticides in ground and surface water
       from agricultural uses.

     It is time to evaluate these concerns; to state the evidence for adverse effects and the benefits
of maintaining healthy turf; and to present the best possible alternatives. We believe an integrated
pest management program can be devised that will promote a more sophisticated use of pesticides,
control turf pests and still maintain highest turfgrass quality. Such a program will preserve the useful
life of valuable pesticides, and provide cost savings for those who implement it.

     A planned demonstration project based on this program should provide a comparison of the
results of several management methods and information on the extent of movement of pesticides
from turfgrass into groundwater and surface water. This information thus addresses EPA's concerns
that people must reduce pollution of all kinds at the source. Based  on sound ecological principles
this program involves conservation of valuable resources.

     Different sites will have different pest problems and different maintenance requirements. For

Home lawns:  A healthy stand of the appropriate variety of grass, properly irrigated and fertilized,
              will rarely require fungicide treatment, will have minimal insect damage, and will
              have a weed population manageable without herbicides.

Golf courses:  Because golfers' demands present special grass stress problems, superintendents
              need to use fungicide treatments for certain areas to lower disease pressure when
              weather conditions indicate potential problems. These chemicals must be applied
              before disease is expressed to  control certain diseases effectively. The current
              practice is to apply fungicides to all vulnerable areas on a calendar basis.anticipating
              disease outbreaks at certain times of the year, dependent on weather conditions.

     Groundskeepers have experienced difficulties with disease control under this system because
of the toxic effects of fungicides on the turf and the buildup of resistance of disease organisms to
fungicides. If a disease is misdiagnosed,  repeated  treatment with the wrong  chemical  can be
disastrous to the turf.

     An  integrated  pest  management system  advocates careful monitoring,  and the chemical
industry, interested in  proper application of their products, has now developed diagnostic kits that
are quick, simple to run and very accurate  in predicting the outbreak of disease. Superintendents
are finding that they can rely on such products to identify the  disease organism and to avoid
unnecessary treatments, thereby preserving the effectiveness of the chemicals. The  savings in
treatment costs more than compensates for the cost of  the kits, and the chemical industry still
benefits  in the marketplace.

     The public has expressed concerns about the emphasis placed on chemical control of turfgrass
pests by the professional lawn care operators and about  homeowner use of  the non-restricted
pesticides registered for turf. The Professional Lawn Care Association of  America is  concerned
about new State regulations on posting. A number of companies now offer alternative  service
programs to their customers and give advice on proper cultural management. The acreage of urban
turfgrass has increased greatly in the last ten years, and the acreage under treatment by lawn care
companies has doubled (see the chapters by Raupp, Potter and Welterlen). We are encouraged
that the industry is taking steps to alter its practices, as shown in the chapters by Jim Wilkinson and
by Roger Funk.

     Very few studies have been done to determine the downstream impact of  the increased use
of pesticides on the growing urban area. Studies such as those reported by Welterlen take  several
growing  seasons to complete and can be very complex in design and costly to run. Research on
the impact of urban pesticides on water resources should be considered an important  part of the
investigation carried out at land grant colleges as a part of their mission.

 In summary, we believe that:

     • the turfgrass industry in general can become  more sophisticated in their pest control
       programs and

     • integrated  pest management programs are  designed to maximize proper use  of

     Unnecessary use of any chemical is of benefit to no one and  is a waste of valuable  resources
Our society can no longer afford to ignore such practices.

     The monitoring methods, biological alternatives and cultural practices discussed in this book
will greatly benefit the golf course industry as well as the growing lawn care service industry by
providing information on a number of control methods and how to design the best program for their

     We hope that this book will contribute to a greater understanding of best management practices
for turfgrass and will supplement turfgrass and landscape management courses. We hope that it
serves as a comprehensive source of information for anyone from city managers to homeowners
who wants to learn how to maintain healthy turf.

     I acknowledge the gracious cooperation of my  authors  in providing their material  under
sometimes very short deadlines. Especially I would like to acknowledge the expert work of Randy
Bacon, of EPA's print shop, who has made my work easy by his management of the text as it arrived.

     Thanks are due to Charles Reese, Chief of the Certification and Training Office of OPP, who
offered to provide funding for the project because he saw the need for material on integrated pest
management in the training program.

     I am especially indebted to Diana Home, Chief of EPA's Integrated Pest Management Unit,
who has enthusiastically supported this work through all  the administrative travails of the project,
and to Joyce Herbert, who has provided exceptional clerical and secretarial service from the time
the symposium was first planned.


         SECTION I
      Problems Encountered in
       Controlling Pests with
        Chemical Toxicants


                                   Robert L. Metcalf
                               Department of Entomology
                                  University of Illinois
                                   Urbana, IL61801

     That insect pests acquire resistance or tolerance to insecticide action has been known for 73
years, since the description of  lime-sulfur  resistance in the  San Jose scale Quadraspidiotus
perniciosus in California (Melander 1914). In 1916, resistance to hydrogen cyanide fumigant was
reported in the California red scale Aonidiella aurantii and in the black scale Saissetia oleae (Quayie
1922). The number of scientifically validated cases of insecticide resistance increased gradually
and by 1946 insecticide resistance was known in a total of 11 species including the codling moth
Cydia pomonella and the peach  twig borer Anarsia iineatelia to lead arsenate, the citricola scale
Coccus pseudomagnoliarum to hydrogen cyanide, the citrus thrips Scirtothrips citri to  potassium
antimonyl tartrate (tartar emetic),  the walnut husk fly Rhagoletis completa to cryolite, and the cattle
ticks Boophiius microplus and EL  decoloratus to sodium arsenite dip (Metcalf 1955). This evidence
suggested that the prognosis of the chemical control of insects was poor. However, little scientific
attention was given to insecticide  resistance which is nothing more than accelerated microevolution.
Insecticide  resistance began to  receive the scientific  attention that it  deserved following  the
introduction of DDT after World  War II  when resistant strains  of the housefly Musca  domestica
appeared almost simultaneously in Sweden and Denmark in 1946; of the mosquitoes Culex pipiens
in Italy and Aedes solicitans in Florida in 1947, of the bedbug Cimex lectularius in Hawaii in 1947,
and of the human body louse Pediculus humanus in Korea and Japan in 1951 (Brown and Pal 1971).

     With the steady proliferation of new insecticides and their increasing use in insect control
programs, the number of scientifically documented cases of insecticide resistance has increased
at an exponential rate, encompassing 224 species in 1970, 364 in 1975,  and 447  in 1984 (Table
1, Georghiou 1986). Although most early examples of insecticide resistance were found in insect
vectors of human diseases because of the very widespread use of DDT, lindane and dieldrin in

     vector control programs, by 1970 insecticide resistance was demonstrated in 118 pests of
crop, forest, and stored products as compared with 166 pests of humans or animals (Brown 1971).
By 1980, resistance was established in  260 agricultural pests compared to 168 pests of humans
and animals (Georghiou, 1981). These figures probably understate the severity of the  resistance
problem worldwide because the susceptibility of many insect pests species has not been studied,
is incompletely characterized, or is not reported adequately in the scientific literature.

     Insecticide resistance has been documented  in 16 orders  of Arthropoda with the distribution
recorded by Georghiou (1981) as: Acarina, 53 (12.4%); Anoplura, 6 (1.4%); Coleoptera, 64 (14.9%);
Dermaptera  1 (0.2%); Diptera, 153 (36.7%); Ephemeroptera,  2 (0.5%); Hemiptera, 20 (4.7%);
Homoptera, 42 (9.8%); Hymenoptera, 3 (0.7%); Lepidoptera, 64 (14.9%); Mallophaga, 2 (0.5%);
Orthoptera, 3 (0.7%); Siphonaptera, 8 (1.9%); and Thysanoptera, 7 (1.6%). These data reflect the
relative numbers of pest species  in the  individual  orders and the amount of insecticide pressure
placed upon them.

     As each new class of insecticides was introduced and widely deployed against insect pests,
the rate of development of resistant species has followed an almost identical pattern of essentially
exponential growth until high-level  resistance or legal  restrictions slowed further  usage.  These
curves are best characterized  by  the doubling  times  over  the  middle  range. These can be
approximated by the data in Table 2, as DDT/methoxychlor  6.3  years, lindane/cyclodienes 5.0
years, organophosphates 4.0 years, carbamates 2.5 years, and pyrethroids 2 years. Thus these
data show that the doubling time for the development of numbers of resistant species has steadily
decreased with the introduction  of each new type  of insecticide. This is corroborated  by the
decreasing spans of effectiveness of substitute insecticides to such pests  as the Colorado potato
beetle  Leptinotarsa decemlineata (Forgash  1984), the Agromyzidae  leaf miner Liriomyza trifolii
(Parrella and Keil 1984),  the citrus  thrips (Morse and Brawner 1986)  and the house fly (Keiding
1977) as illustrated in Tables 3  and 4. This accelerated development of multiple resistance is a
product of the persistence of R genes in the species genome and of  their interactions through a
variety of resistance mechanisms that affect both the detoxication of and the target-site sensitivity
to various insecticides.

     Insecticide resistance is dependent upon random mutation that establishes an R-allele in the
 natural population of the species. Widespread application of the insecticide propagates the R-allele
 through preferential survival and it is dispersed throughout the population. As the R-allele becomes
 sufficiently common, the effectiveness of the insecticide is reduced. Where the R-allele is partially
 dominant, RR homozygotes are rapidly selected that are completely resistant. With recessive alleles
 or combinations of genes each conferring  low-level resistance, selection is much slower (Sutherst
 and Comins 1979).

     There is surprisingly little data about the natural frequency of resistance alleles. These are
 thought to be present in typical insect populations at frequencies of 10'4 to 10~2 with RR homozygotes
 present at 10~8 to 10"4 (Georghiou and Taylor 1986). The most carefully studied example  is that of
 Anopheles gambiae in West Africa (Hamon and Garrett-Jones 1963). In this vast region, dieldrin
 was  used as the  primary insecticide for WHO  malaria  eradication  programs because of its
 persistence on the mud surfaces of dwellings. Initially dieldrin was very effective against A.  gambiae
 adults with LC50 values as low as 0.02 -0.07% based on a 1 hour exposure to treated filter papers
 as producing 24-hour mortality (Armstrong 1958). The corresponding value for DDT was 0.6%.

      Dieldrin spraying  began in 1954 and dieldrin-resistance was first observed  in the Sokoto
 Province of northern Nigeria that had been sprayed 3 times over 18 months. Within 2 months after
 spraying, large numbers of A, gambiae were observed resting, unaffected upon treated walls and
 the LC50 was 2.0% dieldrin (Armstrong et al. 1958). Laboratory colonization produced a RR strain
 that was unaffected by 4.0% dieldrin test papers and had resistance-ratios of 800 for dieldrin, 400
 for aldrin, 140 for isodrin, 90 for endrin, and 26 for lindane, but no resistance to DDT (Brown and
 Pal, 1971). Crossing the R-Ambursa strain with a S-Lagos strain produced RS heterozygotes exactly
 intermediate  in resistance  and the RS, and RR alleles could  be distinguished in field populations
 by exposure to standard WHO test  papers, of 0.4% and 4.0% for 1 hour. By this technique, it was
 shown that resistant heterozygotes formed 0.04% of the wild unsprayed A, gambiae ara'biensis
 population in Diggi  and 6.0% in Sokoto (Armstrong et al. 1958). A single large scale treatment of
 lindane (HCH) produced a population of 86% RS and RR genotypes.  In Upper Volta in an area
 near Bobo-Dioulasso which had been sprayed 4 times with dieldrin, there was 100% RR genotype
 No mortality was produced by exposure to 4.0% dieldrin papers, as compared to an LC50 of 0.03%

in an unsprayed village 40 km. away (Brown and Pal 1971). Areas where A gambiae had high
frequencies of RS and RR genotypes have appeared in Ivory Coast, Ghana, Togo, Dahomey and
Cameroon  (Hamon and Garrett-Jones 1963). Surveys have shown 91-100% RR homozygotes in
Liberia, Dahomey, Cameroon.and Republic  of Congo. There is  evidence that increases in the
frequency of R alleles may be related to the heavy use of dieldrin and lindane on agricultural crops
such as cotton and peanuts. The dieldrin resistant mosquitoes have sporozoite indices as high as
neighboring susceptible populations and dieldrin resistant strains have been found  to be larger,
longer-lived, and more stress-resistant than susceptible strains (Davidson 1956,1958; Hamon and
Garrett-Jones 1963).  Thus the failure  of dieldrin residual spraying has always resulted in the
resumption of malaria transmission.
                           RESISTANCE MECHANISMS
A.   Cross Resistance.   This is the most common form of insecticide resistance where a single
detoxication process or an aberrant intoxication process reduces the susceptibility of resistant
alleles of an insect pest species to a chemically related family of insecticides. Cross resistance has
been demonstrated in naturally occurring arthropod populations to discrete groups of insecticides
classified  in order of historical appearances  as I DDT/methoxychlor,  II  lindane/cyclodienes,  III
organophosphates, IV carbamates, and V pyrethroids. As shown in Table 1, many insect pest
species have successively acquired resistance to these various classes of insecticides. In general,
races of insects resistant to one insecticide in a class exhibit a spectrum of abnormal responses to
all the other members of the class as dictated by their individual stereochemical peculiarities.
B.   Multiple Resistance  is defined as resistance extending to a variety of classes of pesticides,
unrelated  to one another chemically. The mechanisms typically involve target site insensitivity e.g.,
the kdr mechanism that shows reduced sensitivity of the nerve axon to DDT as well as to the
chemically unrelated pyrethroids; and  the altered acetyicholinesterase mechanism where  both
organophosphates and carbamates fail to react with the modified catalytic site of the enzyme due
to a structural modification that restricts access of the chemical inhibitor. Multiple resistance is now
present in at least 213 arthropod species from 10 orders and 44 families (Table 1). Thus almost
half of all the documented cases of arthropod resistance to  insecticides comprise  resistance  to
several chemically unrelated classes of insecticides: I DDT/methoxychlor, II lindane/cyclodienes, III
organophosphates, IV carbamates, and V pyrethroids. By 1987, at least 19 arthropod pest species
are resistant to all 5 classes of insecticides as identified in Table 5.
This extensive and ever widening pool of species with multiple-resistant genes is the product of the
historical replacement of insecticide as resistance developed,  by insecticides of different chemical
types and modes of action. Each new insecticide produces a selection for one or more mechanisms
of resistance and each mechanism selected produces a spectrum of cross-resistance to closely
related insecticides. Thus the sequential use of alternative compounds  has led to widespread
multiple resistance and the continued selection pressure favors the retention of resistant genes to
discontinued insecticides.  Therefore the presence of alleles for  multiple resistance  in  a  pest
population reflects  the  past  history of  insecticide use and  precludes  a return to insecticides
previously used. The devastating effects of cross-resistance and multiple  resistance  to  control
programs  for the Colorado potato beetle attacking potatoes and the house fly in Denmark are shown
by the sequences of resistance development portrayed in Tables 3 and 4.  Similar portrayals of the
development of multiple resistance have occurred with the serpentine leaf miner and the German
cockroach (Section V-C).

The  past history  of selection for resistance may result in an accumulation of  mechanisms for
resistance that confer multiple resistance across the various classes of insecticides. For example,
an esterase in the housefly (E.O. 33) selected by exposure to the organophosphate malathion and
trichlorfon confers moderate resistance to the pyrethroids as well (Sawicki et al 1984). However, in
houseflies  with the kdr mechanism  for resistance selected  by exposure to DDT, subsequent
exposure to the pyrethroids resulted  in intensification of both  the kdr and esterase mechanisms
leading to total immunity to deltamethrin (LD50 greater than 20 ug per fly) (Sawicki et al 1986). Thus
a history of  sequential use of DDT followed by OP's produced a genetic history of multiple resistance
that  contributed to the  rapid  failure of a third group of insecticides, the pyrethroids. There is,
therefore, valid concern that the effective lifetime of the pyrethroids may be shorter in developing
countries where their  use directly succeeded that of  DDT  than it will be in developed countries
where the sequence after DDT involved several years of use of OP's and carbamates (Georghiou

C.   Genetic and Biochemical Processes of Insecticide Resistance.

     A number of increasingly more generalized mechanisms for insecticide resistance have been
identified in terms of specific genetic control (Plapp  1986). Most of these studies have been made
with the housefly  but the types of resistance have been  identified in many other insects and there
is little reason to question their generality.

     Metabolic  resistance involves detoxication  of the insecticides by  a variety  of enzymatic
processes  including  esterases,  mixed  function oxidases,  glutathione  transferases,  and
epoxyhydrolases. Genes on chromosome II are the controlling factor and this may be a common
codominant resistance gene controlling a variety  of detoxifying enzymes (Plapp 1986). Metabolic
resistance  involves DDT, OP's, carbamates, and juvenoids and the specific detoxication enzymes
are  typically inhibited by synergists that may act to  restore the effectiveness  of the pesticide.
Examples  include (a) the  DDT'ase  inhibitor 1,1-bis-(p_-chlorophenyl)-ethanol (chlorfenethol)  for
DDT; (b) Q-ethyl,  Q-(p-nitrophenyl) phenylphosphonate (EPN-oxon) a carboxyesterase inhibitor for
malathion, (c) S,  S, S-tributyl phosphorotrithioate (DEF) for esterases  hydrolyzing OP's;  and (d)
piperonyl butoxide for mixed function oxidases detoxifying carbamates and pyrethroids.

     Kdr or knockdown resistance involves  a modification of the target sites for DDT and the
pyrethroids on the nerve axon and is  controlled by a gene on chromosome III. The kdr resistance
mechanism confers multiple resistance to all  DDT analogues and pyrethroids. Both low level (kdr)
and high level super kdr alleles have been studied.

     Dld-r  or dieldrin resistance involves another  modification of the target site on the nerve axon
and is controlled by an incompletely recessive gene on chromosome IV.

     AChE-R or altered acetylcholinesterase involves a change in the biochemical action of the
nerve synaptic regulator acetylcholinesterase that is the target  site for OP's and carbamates. The
codominant gene is located on chromosome II and confers multiple resistance to organophosphorus
and carbamate insecticides.

     Pen is  a  resistance mechanism  involving  decreased penetration of insecticides and  is
controlled by a recessive gene on chromosome III. This type of resistance can act in concert with
other resistance genes to further increase resistance levels.

1.   DDT'ase.  Resistance resulting  from the selection of alleles that produce  high  levels of a
specific enzyme that catalyzes the dehydrochlorination  of DDT to the  non-insecticidal DDE was
very intensively studied during the 1950's when the  insect resistance picture was  relatively unique
and  simplistic remedies were sought. The enzyme is DDT-dehydrochlorinase or "DDT'ase",and its

high litre produces DDT resistance in the housefly, in the yellow-fever mosquito Aedes aegypti, the
pest mosquitos Culex fatigans. the malaria vectors Anopheles saccharovi, and A^ subpictus. the
human body louse Pediculus humanus. the triatomid bug Triatoma infestans. the Mexican bean
beetle Epilachne varivestis. the red-banded leafroller Argyrotaenia velutinana. the pink bollworm
Pectinophora gossypiella. and the cotton bollworm Heliothis virescens.

DDTase isolated from DDT-resistant flies (Sternburg et al 1954) appears to be a lipoprotein with a
molecular weight of about 120,000 daltons and consists  of 4 subunits. Glutathione is required as a
cofactor  for DDT'ase activity (Lipke and Kearns 1960; Dinamarca et  al. 1969,  1971). DDT'ase
activity is present in the susceptible (S) housefly to only about 0.03 to 0.3% of that in highly resistant
strains (R), and the level of resistance in houseflies where this mechanisms is present is  roughly
correlated with the resistance ratio or RR (LD50R/LD50S)  (Lipke and Kearns 1960; Oppenoorth and
Welling 1976; Oppenoorth 1984).

DDT'ase  functions by attacking the alpha-H  of the  DDT  molecule in  a manner similar to
OH-catalyzed dehydrochlorination, producing an E2-type elimination reaction and the expulsion of
Cl-leading  to the formation of DDE or 2,2-bis-(p-chlorophenyl)-1,1-dichloroethylene  (Figure 1)
(Metcalfand Fukuto 1968). The rates of reaction of various DDT analogues with DDT'ase are similar
to the OH-catalyzed dehydrochlorination constants and are controlled by the relative availability of
electrons at the H-C bond (alpha carbon) as determined by the polar effects of the p_,p_'-substituents
on the aryl rings.  Thus DDT'ase attacks methoxychlor with p,p'-CH3O groups (electron-donating)
at a rate only about 0.2 that of the attack on DDT with p,p_'-CI groups (electron-withdrawing) (Lipke
and Kearns, 1960). The rates of dehydrochlorination by DDT'ase are  also dependent upon the
electronic properties of the substituents on the beta carbon,  and 2,2-bis-(p_-chlorophenyI)-1,1,1-
tribromoethane is attacked about 4X  more readily than DDT. The analogue DDD or 2,2-bis-(p_-
chlorophenyl)-2,2-dichloroethane  is  attacked  about 3.8X more readily  than   DDT, and the
dibromo-analogue of DDD or 2,2-bis(p-chlorophenyl)-2,2-dibromoethane about 4.6X more readily
than DDD (Berger and Young 1962).
2.  DDT'ase Inhibitors as DDT Synergists.  Dramatic demonstration of the role of DDT'ase in
DDT resistance has been provided by discovery that certain structural analogues of DDT, although
insecticidally ineffective, could synergize the toxicity of DDT to highly resistant strains of houseflies.
Chlorfenethol or 1,1-bis-(p_-chlorophenol)-ethanol was found by Summerford et al. (1951) to  have
asynergistic ratio (SR) or LD^ DDT alone/LD^ DDT plus synergist of 60. Chlorfenethol was shown
to inhibit the in vivo detoxication of DDT to DDE in R flies and when a  range  of 0.06 to 6.5u9was
applied topically together with a constant amount of 0.65U9 of DDT, the mortality was increased from
2 to 100%, the amount of DDT recovered internally was increased from 9.4 to 77%, and the amount
of DDE formed was decreased from 63 to 12% (Perry et al 1953). Chlorfenethol  proved to be an
effective in vivo inhibitor of DDT'ase at a molar ratio of 0.001 that of DDT (Lipke and Kearns 1960).
Many other structural analogues of DDT are synergists for R flies, and synergistic ratios (SR values)
determined for the  R  super  pollard housefly are: 1,1-bis-(p_-chlorophenyl)-ethane  SR  100,
bis-(a-chlorophenyl)-chloromethane  SR 140,  and 1,1-bis-(p_-chlorophenyl)-2,2,2-trifluoroethanol
SR 78-127 (March et al  1952; Metcalf,  1967). The high activity of  p_-chlorobenzenesulfon-p_-
chloroanilide SR 108 was described by Speroni (1952) and emphasized the structural similarity of
such compounds to DDT. This led to the development of p_-chlorobenzene-N,N-dibutylsulfonamide
as an oil soluble synergist for DDT (Neeman et al. 1957).
These DDT-synergists clearly fit the active site of the DDT'ase enzyme and act as competitive or
in  some  cases as irreversible inhibitors thus blocking the dehydrochlorination of DDT. The DDT
synergists such as Chlorfenethol, 1,1-bis-(p-chlorphenyl)-chloromethane, and 1,1-bis-(p-chlorophenyl)-
ethane were used successfully  in field experiments to control DDT-resistant houseflies (March et

al. 1952). However, the DDT-synergist combinations had only temporary effectiveness in housefly
control and  eventually treated populations developed "super resistance" to the DDT-synergist
combination (March et al. 1952). The widespread development of an alternative DDT-resistance
mechanism in the housefly, the kdr nerve axon insensitivity which was not responsive to synergistic
action (Oppenoorth and Welling 1976), emphasized the inadequacy of the synergist approach.

3.  "Resistance Proof" DDT Analogues.   The relatively greater effectiveness of methoxychlor
to DDT resistant houseflies with high DDT'ase activity and the spectrum of activity of DDT'ase
toward a variety of DDT analogues suggested that analogues in which dehydrochlorination was
hindered or blocked  might be effective insecticides for DDT-resistant insects.  This  requirement
posed a nice problem in finding DDT-analogues which had the proper stereochemical configuration
to be active  intoxicants but were not DDT'ase substrates. Four distinct mechanisms for "resistance
proofing" of the DDT-type molecule have been identified (Metcalf and Fukuto 1968):

     a.   Changing the bond  strength at the alpha-carbon to  substitute alpha-D or alpha-F  for
         alpha-H. The deuterium isotope effect in OH-catalyzed dehydro-chlorination is 6.8. The
         alpha-C-F bond cannot be attacked by DDT'ase.

     b.   Steric hinderance to  interaction with DDT'ase by introduction of an ortho-group of proper
         size as in p_-CI-DDT. This reduces OH- catalyzed dehydrochlorination to 0.17.

     c.   Changing the bond character of the chloromethyl moiety as in 1,1 -bis-(p-chlorophenyl)-2,2-

     d.   Total replacement of aliphatic halogens by CH3 as in the neopentanes or isobutanes or
         by CH3 and  NO2 as  in the nitropropanes (Coats et al 1977). Examples of the effects of
         these changes in  the  DDT  molecule on  toxicity  to the susceptible and  DDT-resistant
         housefly are shown in Fig. 1.

     Several of these "resistance proof "DDT analogues have had serious consideration for practical
     use. DDT-resistant larvae disrupted the Aedes aegypti eradication program in the United States
     (Section VI-A). The DDT'ase of Aedes aegypti differs  from that of the housefly in effectively
     dehydrochlorinating o-chloro-DDT  but  not  alpha-deutero-DDT (Kimura and Brown 1964).
     Therefore the use of alpha-deutero-DDT which dehydrochlorinates at a rate of about 0.14 that
     of DDT was proposed as a substitute in the eradication program. The relative LC50 values for
     aipha-deutero DDT and DDT to S- and R- Aedes aegypti larvae  were (Pilai et al. 1963):
               S     0.012 ppm
               R    31.0 ppm
 0.004 ppm
  0.40 ppm
     However, the substitution of alpha-deutero-DDT at $10 per Ib. for DDT at $0.20 per Ib. posed
 an unacceptable reduction in the cost effectiveness of the eradication program.

4.  Kgr resistance factor.   A totally different mechanism  of DDT resistance,the knockdown
resistance or kdr mechanism was first identified in the housefly in 1951 (Winteringham et al. 1951).
The kdr mechanism is a target site insensitivity of the nerve axon and evidence for it is obtained
largely by electrophysiological measurements of nerve physiology together with the absence of
DDT'ase, the inactivity of DDT-synergists (Georghiou 1980) and kdr resistance to DDT analogs
that cannot be dehydrochlorinated (Coats et al 1977). The development of kdr is controlled by a
gene on Crlll and is recessive. Kdr is widespread in the housefly in northern Europe and was found
in practically all  populations in Denmark (Keiding 1977). Kdr has been  identified in a variety of
mosquito species: Culex fatigans. (X tarsalis, Aedes aegypti. Anopheles albimanus. ^ gambiae.
Ai quadrimaculatus. A^ saccharovi. ^ Stephens!, in the stable fly Stomoxys calcitrans. the horn fly
Haemotobia irritans and the cattle tick EL microplus.  Kdr is also found in a variety of armyworms
and bollworms including Spodoptera exigua. a frugiperda. ^ littoralis. and Heliothis armigera(Miller
etal. 1983).

The pyrethroids act at the same general target site in  the insect nerve axon as DDT, and  the
introduction of residual pyrethroids in Denmark, Switzerland, Germany, and England was followed
by development of high levels of pyrethroid resistance in the housefly within a few months (Keiding
1980; Keiding 1986; Chapman and Lloyd  1981). In contrast, kdr is rare in Japan and pyrethroid

resistance in the housefly did not develop until after 6 years of residual pyrethroid use (Motoyama

The influence of kdr on multiple resistance of DDT and pyrethroids was demonstrated by the very
rapid emergence of pyrethroids resistance in the horn fly, Haematobia irritans. following the use of
ear tags containing permethrin and fenvalerate on cattle  throughout the U.S. DDT has been used
extensively to control the horn fly during the 1950's and resistance appeared about 1960. The
pyrethroid-containing  ear tags were introduced in  1980 and within  2  to 3 years  widespread
resistance was evident (Quisenberry et al. 1984, Sparks et al. 1985). This resistance resulted from
genetic selection for the kdr mechanism  (Roush et  al. 1986) that resulted  in cross-resistance to
cypermethrin, fenvalerate, permethrin, deltamethrin, and flucythrinate (Byford etal. 1985).

5.  Altered AChE resistance factor.  The enzyme acetylcholinesterase (AChE) is the target site
of the entire groups of organophosphate and carbamate insecticides which number in the hundreds.
Resistance to these insecticides resulting from a decreased sensitivity of AChE was first identified
in the mite Tetranychus urticae (Smissaert 1964). The development of altered AChE is controlled
by a gene on Crll that is codominant, and has been identified in the mites T. telarius. T. kanzawai.
Typhlodromus pyri. Aphis  citricola. the green rice leafhopper Nephotettix  cincticeps. the housefly,
the mosquitoes Anopheles albimanus and Culex pipiens. the cattle tick Boophilus microplus, and
the cotton leafworm Spodoptera littoralis (Nolan et al.  1972; Yamamoto et  al. 1983; Raymond et al.
1986). Kinetic analyses of the enzymes of S and R races have shown a decrease of about 200-fold
in the bimolecular rate constant ki for the inhibition of housefly AChE by tetrachlorvinphos (Tripathi
and O'Brien 1978)  and  of about 500-fold  for the enzyme in the  green  rice leafhopper by
ntsee-butylphenyl N-methylcarbamate (Yamamoto et al. 1983). The phosphorylation or carbamylation
constants, k,, were not appreciably altered but the affinity constants Ka were reduced by 300-500
fold; indicating  structural  alterations in the  stereochemistry of  the active  sites of  both fly and
leafhopper AChE, hence the term "altered AChE." In  contrast, for both altered  enzymes there was
only a 2-3 fold difference in the affinity of ACh for the altered enzyme (Yamamoto et al. 1983). The
altered AChE resistance is particularly destructive to insecticide resources as its appearance results
 in wholesale loss of effectiveness of the large groups of OP and carbamate insecticides.

     Once selected for, resistance genes have very lengthy persistence in wild insect populations.
Although gene frequency of a specific resistance allele may decrease upon removal of insecticide
pressure, the persistence  of an apparently  changed background of residual inheritance in the
genome  causes the strain  to regain its resistance  as soon as the insecticide is reapplied (Brown
1977). Genes for DDT and cyclodiene resistance in Danish houseflies have persisted for more than
20 years; these insecticides again became ineffective within 2 months after reapplication of the
insecticides. Genes for resistance to diazinon and dimethoate also have shown  long persistence
(Keiding  1977). The citrus thrips, Scirtothrips citri  has  retained its resistance to tartar emetic for
more than  45 years and to DDT for more than 35 years (Morse and Brawner 1986). Multiple
resistance in the cotton leafworm in Egypt showed no signs of regression over an 11-year period
(El-Sebae 1977).  There also appears to be no sign of regression of resistance in the multiple
resistance patterns of the Colorado potato beetle (Table 3) and the house fly (Table 4) over periods
of as much as 30 years.

     These  unpleasant consequences of  the segregation of R-genes are  predictable from the
Hardy-Weinberg equilibrium which predicts that gene  frequencies and genotype ratios in large
biparental populations reach an equilibrium  in one generation and remain constant thereafter unless
disturbed by natural selection, new mutations, or genetic drift. This factor, therefore, prevents the
successful  long-term reuse of any insecticide in insect populations with resistance alleles, even
though the initial resistance has apparently reverted to full susceptibility (Brown 1971; Georghiou
and Taylor 1976; Keiding 1979).


    The onslaught of cross and multiple resistance has greatly complicated the chemical control
of individual insect pests (Georghiou, 1981) and jeopardized highly structured eradication programs.
A few examples will suffice to illustrate the severity of the problems.

A.  Colorado Potato Beetle, Leptinotarsa decemlineata.   This native American insect is the key
pest of the Irish potato and fed on buffalo burr, Solanum rostratum until about 1859 when it was
found attacking the potato SL tuberosum in eastern Nebraska. The beetle rapidly accommodated
to this new host and migrated eastward until it reached the Atlantic Coast in 1874 (Casagrande
1987). Paris green or copper acetoarsenite was found to control this insect in 1865 and was replaced
by lead arsenate as the standard remedy until the introduction of DDT in 1946. Resistance to DDT
developed in New York in 1949, North Dakota in 1952 and Minnesota in 1959. The beetle was
introduced into Europe after World War  I and has become a major pest of potatoes there and
resistant genes are  now ubiquitous. Subsequently resistance  has developed to lindane and the
cyclodienes, to a wide variety of  OP's,  carbamates, and pyrethroids. Since  1945,  at least  12
insecticides have been used on Long Island to control this insect and, as shown in Table 3, all of
them  have failed due to the onset of multiple resistance (Forgash  1981). This accumulation of
resistance genes has progressively decreased the interval of effectiveness so that since 1973  no
insecticide has remained effective for more than 2 years. In the words of Forgash (1984) "the fact
is we  are rapidly running out of control materials for the Colorado potato beetle in certain areas of
the Northeast....where do we go from here?"

B.  Serpentine leaf miner, Liriomyza trifolii.  This insect was a minor pest of ornamentals,
vegetables,  and cut flowers until the use  of the broad spectrum  insecticides chlordane and
toxaphene in Florida destroyed its natural enemies and resulted in huge population resurgences,
following the development of resistance about 1957. Since 1975, no insecticide has given effective
control for more than 2-4 years and there is widespread  multiple resistance to the cyclodienes,
OP's, carbamates, and pyrethroids. Subsequently, the resistant race was imported  into California
(Parrella and Keil 1984), and pest control costs have  risen to $6,000 per acre. By 1984, as  all
registered insecticides were ineffective, the leafminer problem "had become so serious that it has
threatened the chrysanthemum industry throughout the United States and the  celery industry in
Florida"(Parrella and Keil, 1984).
C.  German  cockroach, Blattella germanica. is the most ubiquitous of urban  pests  and is
responsible for the great majority of requests for the services of professional pest control operators
(PCO's) as well as for the  preponderance of insecticide applications to the interiors of urban and
suburban structures  (National Academy of Sciences 1980). Although other species of domestic
cockroaches are household pests including the oriental cockroach Blatta orientalis. the American
cockroach Periplaneta  americana. the  smoky brown cockroach P. fuligenosa. the Australian
cockroach P..  australasiae and the brown banded cockroach  Supella longipalpa: the enormous
populations of the German cockroach and its almost universal exposure to insecticides have brought
about the most acute problems of insecticide resistance.
The German cockroach was initially of only moderate susceptibility to DDT (topical LD50 ca 50  ug
per g, Heal 1953). True DDT resistance was first demonstrated in Trinidad and  Panama in 1959,
and in Canada, Germany, France, and England in 1961  (Grayson  1966). Laboratory colonies have
shown DDT  resistance ratios (RR values) as high as 200X (Grayson 1953). Chlordane (topical
LD-Q ca 20 ug per g), (Heal et al. 1953), was substantially more effective than DDT and became the
insecticide of choice for cockroach control from 1948-1952 (Kearns et al. 1948). However, a strain

of EL germanica collected in Corpus Christi, Texas in 1952, where control failures with chlprdane
had been experienced, was found to have RR values of 5-6 for DDT, 10-12 for lindane, and 100-200
for chlordane (Heal et al. 1953). By 1953, chlordane resistance had appeared generally in the Gulf
States of the U.S. and sporadically elsewhere and diazinon and malathion were recommended as
substitute insecticides. Cyclodiene resistance was demonstrated in Europe by 1961 and RR values
of 5,000 to chlordane and 6,000 to dieldrin were reported (Green  et al. 1961). Chlordane resistant
EL germanica were cross resistant to heptachlor, aldrin, dieldrin, and lindane (Fisk and Isert 1953;
Butts and Davidson  1955)  and  a strain collected from  Hawaii showed RR value for females of
chlordane 322X, dieldrin 194X, lindane 27X, DDT 6X, malathion 8X, naled 3X, and the carbamate
propoxurSX (Ishii and Sherman 1965).

Resistance to diazinon was demonstrated in roaches collected near Owensboro, Kentucky in 1959
(Grayson 1961) and  resistance to  malathion had apparently appeared by 1959-1960 and was
conclusively demonstrated in 1962 (Johnston et al 1964). Cross  resistance among  diazinon,
malathion, and fenthion was widespread in major Texas cities by 1964 (Grayson 1965).

Pyethrins resistance at RR levels up to 20-31X was found in a strain of EL germanica collected at
Fort Rucker, Alabama in 1954 (Keller et al.  1956) and three strains collected in Texas in  1963 had
RR values of 10-15X (Grayson 1966).

Resistance to the carbamate bendiocarb appeared in England in 1977 (Barson and McCleyne 1978)
and the  roaches  were  cross resistant to  dioxacarb and showed  resistance to diazinon, and
malathion, with weak resistance to  permethrin (Barson and Renn 1983). A strain of the German
cockroach from Baltimore, Maryland was highly resistant to bendiocarb (RR 90X) and had cross
resistance to propoxur (RR 13X) and resistance to diazinon  (4X), malathion (6X), and chlordane
(8X) (Nelson and Wood 1982). German roaches with kdr type resistance to  DDT were found to
have resistance to  pyrethrins,  allethrin,  permethrin, fenvalerate,  and marginal  resistance  to
cypermethrin, but none to deltamethrin.

Chlordane  resistance in JL germanica has been shown to be stable over 25 generations  of
non-exposure and malathion resistance for  13 generations (Grayson 1966). A major consequence
of the widespread multiple resistance in this  species has been the introduction of more acutely toxic
OP compounds into human dwellings and the workplace, e.g., the replacement of malathion (rat
oral LD501250 mg per kg) by chlorpyrifos (rat LD50 97) and propetamphos (rat LD50 82).
                           ERADICATION  PROGRAMS

     The development of DDT and its successful initial uses in controlling the mosquito, louse, and
flea vectors of such dreaded human diseases as malaria, yellow fever, typhus, and plague afforded
remarkable visions of mass public health programs for the abatement and eventual eradication of
these and other vector-borne diseases throughout  the world. DDT was safe to humans even when
applied in the intimacy of dwellings, inexpensive and highly persistent in its effectiveness in all sorts
of environmental situations. Thus  it was possible to secure financing  for major public health
programs that naively promised eradication of disease vectors by the domestic application of DDT
over periods of only a few years. The projected costs of such programs although reckoned in tens
to hundreds of millions of dollars, have proved in retrospect to have been grossly underestimated
and the eventual magnitude of the operations was  such that the original goals have been lost and
"eradication" has quietly slipped  into oblivion. Vector resistance to DDT and to subsequently

developed cheap and durable insecticides such as lindane and dieldrin has been the principal
technical problem leading to steadily worsening control failures.

     DDT resistance appeared in the housefly Musca domestica and in Culex molestus in Italy in
1947, in the human body louse Pediculus humanus in Korea and in Anopheles saccharovi in Greece
in 1955, and in the oriental rat flea in India in 1959. The rapidly increasing number of vector species
for which insecticide resistance was suspected  as the cause  of control failures are shown as
(Quarterman and Schoof 1958).
     However, these abundant warning signs were virtually ignored in planning and operating vector
 eradication programs with the result that  monumental  failures have resulted as shown in the
following examples. The ultimate failures of these programs represent an enormous disaster to the
cause of global public health and are the most extravagant economic tolls yet levied by insect

A.   Aedes aegypti eradication.   This domesticated mosquito, the urban vector of yellow fever
and dengue fever, was introduced into the Americas from its native  home in Africa before the 16th
century. For hundreds of years,  the presence of  Ae. aegypti was responsible for devastating
outbreaks of yellow fever in seaports throughout the Americas. By 1930, the mosquito was present
in 19 countries and ranged from Oklahoma and Tennessee in the United States to Buenos Aires
in Argentina and Tecopila in Chile (Gratz 1973). Ae. aegypti is the vector of the several serotypes
of dengue fever virus and the number of reported cases in the Americas reached 503,000 in 1977
and 354,000 in 1982 (Tonn et al. 1982).

The concept of a hemispheric eradication program for Aedes aegypti was first proposed by the 11th
Pan America Sanitary Conference in Rio de Janeiro in 1942, and by 1947, the Pan American Health
Organization (PAHO) officially embarked in the eradication of the mosquito as the solution to the
urban yellow fever problem.  By 1960,  the  United States was the only country in the mainland
Americas that had not initiated  an Aedes aegypti eradication program. Strong political pressures
resulted in  a Congressional appropriation of $3 million in 1963 for operations the succeeding year.
The major weapon relied upon was the "perifocaP'application of DDT water dispersible suspension
in and around all potential breeding places of the mosquito and to any adjacent wall surfaces within
a radius of about one meter (Gratz 1973).

The  eradication effort  was thus essentially doomed because DDT-resistance  had  been
characterized in Aedes aegypti  in  Trinidad as early as 1950 (Brown and Pal 1971), and a survey
of the mosquitoes' susceptibility throughout  16 countries of the Americas had shown that by 1964
no populations could be  found that were susceptible to either DDT or dieldrin (Kerr et al. 1964).
Initial control failures in the U.S. demonstrated that it would be necessary to replace the relatively
cheap organochlorines with more costly and  less persistent organophosphorus insecticides and
these economic dislocations resulted in the quiet demise of the eradication program in 1968 after
the expenditure of $54 million. A PAHO report in 1970 estimated that  it would cost an additional
$250 million and require another 5 years to eradicate Ae, aegypti from the U.S (Gratz 1973).

Presently A. aegypti is known to have multiple resistance to DDT, cyclodienes, OP's and pyrethroids
(Georghiou 1981),  and  it seems most unlikely that eradication can be accomplished by chemical

B.  Malaria Eradication.   The onset of insecticide resistance has produced its most deleterious
effects in the control of  malaria. Malaria has long been called the king of diseases and before the
advent of DDT annually caused about 300 million illnesses and 3 million deaths. During World War
II, the  persistence  and  efficiency of DDT residual sprays against a variety of mosquito species
entering human habitations suggested that yearly spraying of all dwellings in malarious areas could
eliminate the disease by killing female Anopheles mosquitoes over the 10-14 day period required
for infective sporozoites to  develop in the mosquito's body following the ingestion  of male and
female gametocytes from a  human blood meal. Application of this control measure directed at the
vector Anopheles labranchiae in Italy in 1944 reduced the number of primary cases of malaria from
4800 in 1946 to 81 in 1949 and malaria was considered eradicated in 1950 (Missiroli 1950). A similar
program in Sardinia using DDT spraying at 2 g per m2 on the interior walls of houses eradicated
malaria in 1951 (Logan  1953). In India 3-4 years of DDT residual spraying against the vectors ATL
culicifacies and An. fluviatilis reduced the parasite rate to less than 0.05% of its former  level and
by 1954 at least 64 million inhabitants were under protection of DDT spraying. These and successes
in other parts of the world set the stage for the 1955 World Health Organization's program for the
global eradication of malaria to be accomplished  by residual house spraying with DDT at 2g  per
m2 or with dieldrin at 0.6 g per m2. It was planned that 8 years of continuous operations would be
required for eradication in each national program and the entire global eradication was estimated
to cost $1.3 billion (Brown et al. 1976; Soper et al. 1961).

DDT resistance was first observed in An. saccharovi in Greece in 1950  and was followed by dieldrin
resistance in  1954. The onset of resistance was marked by a deterioration in malaria control that
has continued for more than 30 years, with sporadic epidemics of  malaria (Brown and Pal 1971).
Resistance in An.  saccharovi is now found in Greece, Lebanon,  Iran,  and Turkey and multiple
resistance to  DDT, dieldrin,  malathion,  fenitrothion,  propoxur, and permethrin  has  been

Pronounced DDT resistance appeared in An. Stephens! in Iran and Iraq when full scale residual
spraying operations were begun in 1957-58. Dieldrin resistance appeared three years later, followed
by malathion resistance in 1975 after six years of use (World Health Organization 1976).

In Central America and  the Caribbean, dieldrin spraying  against An. albimanus was begun in 1956
and widespread resistance appeared in 1958. A return was made to DDT spraying, and resistance
appeared in 1958 and was  general by 1960. The effective carbamate propoxur was  employed in
Guatemala, El  Salvador, Honduras, and Nicaragua in 1970-71, and  pronounced resistance had
developed by 1974. ATK albumanus now shows  multiple  resistance to DDT, dieldrin, lindane,
malathion, propoxur, and permethrin (World Health Organization 1981).

ATL culicifacies is the principal vector of malaria in India, Pakistan,  and Sri Lanka. This vector
developed dieldrin  resistance in India in 1958 and DDT resistance in 1959  after three years of
spraying,  but a widespread malaria eradication program was continued until  1965-66 when both
DDT and BHC failed to control outbreaks of malaria in areas under consolidation and maintenance
(Brown and Pal 1971). Malathion  was substituted in 1968 with some success,  but widespread
epidemics of malaria were reported in 1975 with 4 million cases as compared to 125,000 in 1965.
In Pakistan, the experience  was similar with DDT resistance appearing in An. culicifacies in 1963.
The importance of this  resistance was not recognized until outbreaks of malaria began in 1969.
Neither DDT nor lindane was effective. By 1975 malaria cases in Pakistan were reported to number

over 10 million as compared to 9,500 in 1961. Malathion resistance appeared in An, culicifacies in

The problems of the rapid development of BHC and dieldrin resistance in An. gambiae in Africa
have been discussed in Section II.

Many other examples of insecticide resistance  in Anopheles spp occurred throughout the world,
and by 1981 multiple resistance was present in  52 of the 60 vectors of malaria as shown in Table
6 (World Health Organization 1981).

Malaria eradication through residual house spraying reached a high point in 1974 when the malaria
was considered eradicated in 36 countries; the population in areas in the maintenance phase and
essentially without risk had increased  to 797 million or 41.2% of the population in the areas of
endemic malaria  (Brown  et al. 1976). However,  malaria eradication  programs in Saudi Arabia,
Somalia, Burma, Cambodia, and South Viet Nam had reverted to organized control programs

covering a population of 168 million. Parasite rates remained high in Africa, Southern Asia, and
parts of Central America involving  about  100 million people. Massive epidemics of malaria had
occurred India and in Pakistan. Thus in the areas where multiple resistance in Anopheles vectors
is widespread malaria eradication efforts have almost completely broken down with some countries
recording 30-40 fold increases in the  number of cases of malaria from 1968 to 1976 (Agarwal
1979). Bruce-Chwatt (1970) stated that "physiological resistance has become one of the major
threats of the success of global malaria eradication", and as of 1976, WHO quietly abandoned the
concept of global  malaria eradication by residual house spraying (WH01978).

     The widening spread of cross and multiple resistance through the genomes of major pest
 insects has severely limited the armamentarium of insecticides effective for the control of insect
 pests. The chronology of control failures with the Colorado potato beetle (Table 3) and the house
 fly (Table 4) provide dramatic confirmatory evidence (see also Section V). The spread of resistance
 has resulted in the wholesale replacement of the organochlorines by organophosphates and these
 in turn are being replaced by carbamates and then by pyrethroids. The progressive substitution of
 newer and more sophisticated insecticidal molecules has caused escalating costs to the users of
 insecticides. On the  average, lindane and the cyclodienes cost about 6 times more than DDT,
 organophosphates 11 times, carbamates 9 times, and pyrethroids 100 times more than DDT. To
 be  sure there are substantial dosage  differences, e.g. the pyrethroids are generally used at rates
 0.05- 0.1 those for DDT. Nevertheless, the cost differential is a major factor for the farmer who is
 bound by essentially static farm prices, and it has been disastrous for public health programs such
 as  the WHO malaria eradication scheme. Based on a cost factor of 1.0 for DDT residual house
 spraying at 2 g per m2, replacement with dieldrin at 0.5g per m2 costs 1.7 times more; with lindane
 at 0.5g, 5.2 times; with malathion at 2g, 5.3 times; with fenitrothion at 2g, 15.9 times; with propoxur
 at 2 g, 20.4 times (Metcalf 1983).  With  the synthetic pyrethroids costing $50-100 or more per Ib.
 and used at 0.1  g per m2; the costs become astronomical. These  cost increases are completely
 beyond the resources of public health  budgets.
     During the past 40 years insecticide-resistant pests have been controlled by the simplistic
 process of changing  to a new type of insecticide to which the pest is susceptible. The widening
 patterns of multiple resistance (Table  1) show that this is  a dubious long term solution. Pesticide
 discovery and development have become increasingly rigorous and costly. In 1956,1800 chemical
 compounds were screened per marketable new product; in 1965-3600; in 1969-5040; in 1970-8000;

in 1972-10,000; in 1977-12,000 and in 1984-22,000 (Johnson and Blair 1972, Menn 1980, Storck
1984). Over this same period, the total developmental costs for marketing a new pesticide in the
United States have increased from about $1.2 million in 1956 to about $45 million in 1984 (Fig. 2).

     Insecticide resistance has steadily decreased the marketable life of new insecticides and cross
and multiple resistance prejudice the effectiveness of new products even before they are marketed.
Thus cross resistance in An. albimanus in El Salvador initiated by the drift of carbaryl from cotton
fields to aquatic breeding habitats of the mosquito, sharply reduced the effectiveness of the related
carbamate propoxur developed  as  a replacement  for DDT in malaria control by residual house
spraying (Georghiou et  al.  1973). Multiple resistance  by the DDT-selected kdr mechanism
predisposes insect pests to rapid development of high levels of pyrethroid resistance (Miller et al.
1983, Omer et al. 1980, Priester and Georghiou  1980,  Georghiou  1986). There is substantial
evidence  that the accumulating genes  regulating  a variety of biochemical mechanisms for
detoxication and target site insensitivity have progressively shortened the effective lifetimes of
succeeding classes of new insecticides (Tables 1  and 2). Insecticide resistance, therefore, has
played a major role in the precipitous decline in the discovery and development of new  synthetic
insecticides that has occurred since 1960 (Table 7).


     The methodology for insecticide use in agricultural and  public health over the past  40 years
has been largely that of endeavoring to  suppress insect pest species to unrealistic levels, i.e.
eradication. Pest species exposed to the massive applications of insecticides made to agricultural
crops,  to pest breeding sites, and to urban and suburban properties have been  under  intensive
"natural selection" in the Darwinian  sense. Species that survived such onslaughts were  forced to
change the nature of the genome by undergoing "accelerated microevolution". Naturally  occurring
mutations that favored survival in an  insecticide laden environment rapidly become dominant as
described in Section II. As shown in Tables 1 and 2, this process of resistance selection has occurred
with disconcerting rapidity for almost all insect pest species. The persistence of resistance genes
in the  insect  pest genome (Section IV), has made it impossible to reverse the historical loss of
insecticide effectiveness as portrayed in Tables 3, 4, and 6.

     Many tactics for resistance  management have been proposed over the past 40 years but few
specific methodologies have been put to practical use. The resistance problem has been addressed
largely by toxicologists and entomologists who have proposed solutions directed solely at insecticide
use, i.e., insecticide management (beeper et al. 1986). Suggested solutions include (a) monitor
insect  pests so that primitive susceptibility levels are understood and early detection of specific
resistance is possible,  (b) avoid use of mixtures of insecticides,  (c) extend the  useful life of a
satisfactory insecticide as long as possible, but monitor susceptibility and replace the insecticide
before it  fails,  (d) choose a sequence  of suitable alternative insecticides based on genetic
considerations affecting  cross and  multiple resistance, and (e) exploit alternative  treatments with
insecticides devoid of common major R factors (Metcalf 1980). The frequently proposed remedy of
incorporating synergists to restore insecticide effectiveness is unlikely to be productive in view of
past experience (Section III-B).  Resistance can rapidly develop to the combination of insecticide
and synergist or through alternative pathways.  The use of  mixtures  of chemicals is subject to
disadvantageous registration and marketing considerations and to environmental quality problems.

     However, resistance is a complex genetic, evolutionary, and ecological phenomenon and
insecticide management is unlikely  to produce other than temporary palliation. As we have seen
(Section VII), the technological and economic requirements for successful insecticide management

are likely to exceed available resources. Resistance management tactics are more likely to succeed
if they are directed at reducing the single-factored selection pressure that occurs with conventional
chemical control. Obvious counter measures include (1) reduce frequency of insecticide treatments,
(2) reduce extent of treatments, (3) avoid insecticides with prolonged environmental persistence
and slow release formulations, (4) reduce the use of residual treatments, (5) avoid treatments that
apply selection pressures on both larval and adult stages, (6) incorporate source reduction and
non-chemical methods, such as biological and cultural controls in control programs (Metcalf 1980).
National programs or policies incorporating  these principles have been organized against the
housefly in Denmark, and the cattle tick and the cotton bollworm Heliothis armigera in Australia
(Keiding 1986).

     The combination of these principles is essentially a blue-print for integrated pest management
(IPM) that is a dynamic framework for insect control practice based around the observance of the
economic threshold before  initiating remedial practices, and that seeks to relegate the use of
insecticides to emergency weapons to be applied as last resort. Within the IPM framework there is
opportunity to consider resistance management tactics based on population genetics, i.e., relating
to the frequency of resistant aileles, decreasing the dominance of resistant genes, and minimizing
the fitness of resistant genotypes (beeper et al.  1986). These proposals require manipulations of
the agroecosystem such as the mass release of susceptible insects, the eradication  of resistance
foci, the application of insecticides at high rate to reduce dominance by heterozygotes,  and reducing
the fitness of resistant genotypes by preserving susceptible homozygotes (Georghiou and Taylor
 1977). Whether such theoretically desirable schemes can be implemented within existing economic,
social, and political constraints is  an intriguing question. (Miranowski and Carlson 1986).

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                                      TABLE 1

Development of Insect Pests with Multiple Resistance to Various Groups of Insecticides1

Resistant DDT

7 0
14 1
25 18
224 42
384 70
428 105
447 119



Brown & Pal (1971)
Brown & Pal (1971)
Metcalf (1955)
Brown (1971)
Georghlou & Taylor
Georghlou (1981)
Georghiou (1986)
1From Metcalf, R.L The ecology of insecticides and the chemical control of insects, pp. 251-297,
in M. Kogan, ed, "Ecological Theory and Integrated Pest Management Practice", Wiley, N.Y. (1986)

                                     TABLE 2

Approximate Rate of Development of Insecticide-Resistant Insect Species, Worldwide
Year Resistance was Attained1
Resistant pests (no.) DDT/ Undane/ Organophosphates Carbamates
methoxychlor cyclodiens
5 1951 1954 1959 1971
10 1952 1955 1962 1972
20 1955 1956 1964 1974
40 1960 1959 1968 1977
00 1968 1965 1972
160 1974 1971 1976
Average Doubling time -years 6-3 5-° 4-° 2-5


1Data from Brown &  Pal (1971), Metcalf (1955), Brown (1971), Georghiou & Taylor (1977a),
Georghiou (1981), and Farnham (1985).

                                      TABLE 3

Development of Insecticide Resistance in the Colorado Potato Beetle Leptinolasa decemiineata.
Azinphos methyl

Year Introduced

Year First Failure

1From Metcalf, R.L. The ecology of insecticides and the chemical control of insects, pp. 251-297,
in M. Kogan, ed. "EcologicalTheory and Integrated Pest Management Practice", Wiley, N.Y. (1986).
Data from Forgash (1984).

                                    TABLE 4
Rates of Development of Insecticide Resistance in the House Fly, Musca domestica. in Denmark.1
Cypermethrin, penmethrin
Year Introduced
Year First Failure
 1Keiding 1977, 1978, 1979.

                                                TABLE 5

                 Insect Pests with Multiple Resistance to Five Classes of Insecticides

Colorado potato beetle, Laptinotarsa decemlineata
Granary weevil, Sitophilus aranarius
Red Flour beetle, Tribolium castaneum
House Fly, Musca domestica

House Mosquito, Culex pipiens

Horn Fly, Haematobia im'tans

Leaf miner, Liriomyza trifolii

Malaria mosquitoes. Anopheles albimanus and An. sacharovi

Brown plant hopper, Niloparvata lugens

Green peach aphid, Myzus persicae

Pear psylla, Psylla pyricola

Armyworms, Spodoptera fruigiperda. &. littoralis

Cotton Bollworms, Heliothis armigera and hL virescens

Diamond back moth, Plutella xylostella
 German cockroach, B|attella germanica
 Citrus thrips, Scirtothrips citri

                                         TABLE 6

Spread of Insecticide Resistance in Anopheles Mosquito Vectors of Malaria1
Number of
                                           Number of Species Resistant to:
Dieldrin/    Organophosphates  Carbamates     Pyrethrolds

















 1Data from Brown & Pal (1971), Georghiou (1981), World Health Organization (1976,1980).

                                   TABLE 7
         Rate of Discovery and Development of New Broad-Spectrum Insecticides1
Number Patented
1From date of original patent (Merck Index 1983).

                              FIGURE 1

Action of DDT'ase in converting DDT to DDE, and relative toxicity of some "resistance proof" DDT
analogues to susceptible (S) and DDT resistant (R) house flies. (Metcalf & Fukuto 1968).
                          Musca domestics

                             LD50 pg  per g

                              S         R
         2.0   >5OOO

                               FIGURE 2

Increasing developmental costs for new pesticides. From Johnson & Blair (1972), Metcalf (1980),
Menn (1980), and Storck (1984).
      	(•      I     Wj^      |	|	|	|	|

      I960           I960            1970           1980           1990


                         Daniel A. Potter, Stephen D. Cockfleld,
                                 Terry Arnold Morris
                              Department of Entomology
                                University of Kentucky
                              Lexington, Kentucky 40546
     Turfgrasses, which cover an estimated 8 to 10 million hectares in the United States (Kageyama
 1982, Tashiro 1987), are typically the most intensively managed plantings in the urban landscape.
 Increasing public demand for dense, uniform, pest-free turf has resulted in a growing number of
 lawns, golf courses, and other turf areas being maintained with regular chemical applications (U.S.
 EPA 1979, National Research  Council  1980,  Anonymous 1984). Gross annual sales  of the
 commercial lawn care industry increased at an average annual rate of 22% between 1977  and
 1984, with ca.  13% of single-family households with incomes  over $20,000 contracting for
 commercial lawn care in 1984 (Anonymous  1984). Total annual expenditures for turfgrass
 maintenance in the United States were estimated in 1983 to be about 15  billion dollars (Tashiro
 1986), with much of this cost allocated to the purchase and application of insecticides, herbicides,
 fungicides, and fertilizers.

     Pesticides and fertilizers are versatile and powerful tools of pest management, and there are
 many pest problems for which the use of chemicals currently provides the  only practical solution
 (Metcalf 1975). However, use of chemicals may also have profound effects on the structure, stability,
 and  resilience of agricultural systems (Pimentel and Edwards 1982). Because pesticides kill
 beneficial organisms as well as pests, their use may increase the risk of pest resurgences or
 secondary pest  outbreaks (e.g. Luck and Dahlsten  1975, McClure 1977, Merritt et al  1983).
 Pesticides and fertilizers may also affect energy flow and nutrient recycling by  altering primary
 production or by disrupting the activity of organisms important to decomposition processes (Edwards
 and Thompson 1973, Pimentel and Edwards 1982).

     Like  many cultivated crops, turfgrass lacks the complexity of natural grassland and forest
 systems, and so would be expected to be relatively susceptible to pesticide-induced perturbations.
 However,  little information exists on the ecological side-effects of pesticide and fertilizer usage on
 turfgrass. The purpose of this chapter is to summarize recent research which has begun to clarify
 the  effects  of common turf management practices on populations of  potentially  beneficial
 invertebrates  in  turfgrass, and  how this  in turn  may affect key processes such as  thatch
decomposition and natural regulation of pest populations.

                         THE TURFGRASS ECOSYSTEM
     Turf grass consists of the  roots, stems, and leaves of grass plants, together with a tightly
intermingled layer of dead and living roots, rhizomes, stolens, and organic debris commonly referred
to as thatch (Beard 1973). This composite habitat supports a variety of plant-feeding insects and
mites which inhabit the soil, thatch, and/or above-ground portions of the grass plants. These  include
a number of familiar pest species that cause injury by consuming roots (e.g., scarabaeid grubs;
billbugs), devouring grass blades and stems (e.g., sod webworms, cutworms, armyworms) or by
feeding upon plant sap and damaging vascular tissues (e.g., chinch bugs, greenbug, winter grain
mite). Biology and host plant relationships of turfgrass insect pests were reviewed by Tashiro  (1987).

     Turfgrass also supports a diverse community of non-pest invertebrates. In one survey (Streu
1973), 11  taxa of nematodes, 83 arthropod taxa including numerous families of insects and mites,
and numerous kinds of  annelids, gastropods, and  other invertebrates were collected  from a
bluegrass-red fescue turf in New Jersey. Pitfall trap surveys and Tullgren funnel extractions revealed
a similarly rich fauna of free-living predators and soil and thatch inhabiting species from turfgrass
areas in Kentucky.  More than 40 species of Staphylinidae (rove  beetles), 30 species of Carabidae
(ground beetles),  10 species  of  Formicidae  (ants),  dozens  of  species of  spiders and other
predaceous arthropods, and large numbers of nematodes, earthworms, Collembola (springtails),
oribatid mites, and other soil invertebrates have been collected from untreated Kentucky bluegrass
and tall fescue turf (Cockfield and Potter 1984, 1985,  Potter et al.  1985, Arnold and Potter 1987).
These pest and  non-pest invertebrates form  a complex community which interacts with the living
grass, thatch, and soil and contributes to the stability of the turfgrass habitat.

                                PEST POPULATIONS
     Pesticides that are applied for control of turfgrass pests are generally also toxic to predators
 and parasites.  For example, a single, surface  application of the organophosphate insecticides
 chiorpyrifos or isofenphos reduced populations of predatory mites, spiders, and insects in Kentucky
 bluegrass by as  much  as 60% (Cockfield and  Potter 1983). Predator populations were still
 depressed more than six weeks after the application (Fig. 1). Given their sensitivity to insecticides,
 it is not surprising that predatory arthropods were found to be less abundant and less diverse in
 high maintenance Kentucky bluegrass sites (i.e., turfgrass that received scheduled applications of
 fertilizers and pesticides) than  in sites that had been maintained without chemical applications
 (Cockfield and Potter 1985, Arnold and Potter 1987) (Table 1). Similarly, spider and ground beetle
 populations were found to be 20-30% lower in lawns receiving preventative insecticide treatments
 in Florida (Short et al. 1981).

     Several authors (Streu and Cruz 1972, Streu and Gingrich 1972, Reinert 1978, Cockfield and
 Potter 1984)  have cautioned that repeated pesticide  treatments could reduce the stability  of
 turfgrass communities and lead to increased pest problems. Nevertheless, documentation of pest
 resurgences or secondary pest outbreaks in turfgrass is somewhat limited. Reinert (1978) observed
 that southern chinch bug (Blissus insularis Barber) populations in Florida remained low in untreated
 St. Augustine grass lawns where predators and an egg parasite were abundant, while at the same
 time reaching outbreak densities on lawns that received repeated insecticidal treatments. Similarly,
 resurgence of hairy  chinch bug populations following several years of chlordane treatment were
 attributed to reduced populations of predatory mites (Streu and Vasvary 1966,  Streu 1969, Streu


and  Cruz 1972), and  possibly predatory hemipterans (Streu  1973). In New Jersey,  carbaryl
treatments over several years were accompanied by outbreaks of winter grain mite (Penthaleus
mjior (Duges)) (Streu  and Gingrich 1972).  These authors suggested that carbaryl  may have
reduced  populations of mite predators.  In  Kentucky, outbreaks of the greenbug (Schizaphis
graminum (Rhondani)) appear to be more common on high maintenance lawns than on untreated
turf (Potter 1982).

     Short lists of natural enemies associated with various turfgrass pests have been published
(e.g., Bohart 1947, Streu and Cruz  1972, Streu and  Gingrich 1972, Tashiro 1973,  Reinert 1978,
Cockfield and Potter 1984). Nevertheless, the experimental evidence that predators or parasites
are important in regulating pest densities in turfgrass  is very limited. Reinert (1978)  observed egg
parasitism and predation  upon southern chinch  bugs in laboratory  trials and in  the field.  He
suggested that the combined predator-parasite complex may have contributed, at least in part, to
an  observed collapse  in chinch bug populations in late summer. Cockfield and  Potter (1984)
collected  sod webworm (Crambus  and Pediasia spp.) eggs from  field-collected  females  and
exposed them to natural predation in Kentucky bluegrass. Predators, primarily ants, consumed or
carried off up to 75% of the eggs within 48 hours. Treatment of half of the plots with a single surface
application of chlorpyrifos to kill sod webworm  larvae significantly reduced predator- induced
mortality of the eggs for at least three weeks (Table 2), while simultaneously reducing the numbers
of predators moving through the turf. To date, this study is the only experimental demonstration
that natural enemies may be important in reducing  pest populations in  turfgrass,  and that this
process can be disrupted by pesticide applications.

     The Greek philosopher and scientist Aristotle called earthworms "the intestines of the earth".
 indeed, earthworms and  other soil- inhabiting invertebrates including nematodes,  millipedes,
 oribatid mites (Acari: Cryptostigmata), Diplura and Collembola are known to play a major role in
 plant litter decomposition and nutrient recycling  in forest and pasture soils. These animals aid the
 decomposition process by fragmenting  and conditioning plant debris in their guts before further
 breakdown by microorganisms (Lofty 1974, Harding and Stuttard 1974, Wallwork 1983). They also
 disseminate bacteria and fungi, enrich  the soil  with their excreta, and help to distribute organic
 matter throughout the topsoil layer (Satchell 1967, Lofty 1974). Plant litter decomposition is generally
 much  faster with  the  combined  influence of  soil animals and microorganisms than  with
 microorganisms alone (Ghilarov 1963). The burrowing action  of earthworms and other soil
 invertebrates is also critical to air and water infiltration in turfgrass. Charles Darwin, considered an
 early authority on earthworms, wrote: "The plough is one of the most ancient and most valuable of
 man's inventions; but long before he existed, the land was in fact ploughed, and still continues to
 be thus ploughed by earth-worms" (Darwin 1907). This process is especially important in lawns,
 golf  course fairways, and other turf areas which are "cultivated" mainly as a result of earthworm

     Excessive thatch results from an imbalance between vegetative production and decomposition
 at the soil surface (Beard 1973). Problems associated with thatch accumulation include restricted
 penetration of fertilizers (Cornman 1952, Nelson et al. 1980), binding of insecticides (Niemczyk et
 al. 1977, Niemczyk 1987),  reduced water infiltration (Taylor and Blake 1982), and shallow root
 growth, with increased vulnerability to heat and  drought stress (Beard 1973). Kentucky bluegrass
 lawns maintained with multiple applications of pesticides and high rates of fertilizer often develop

a thatch problem within 4 to 5 years (Engel and Alderfer 1967, Meinhold et al 1973, Shoulders and
Hall 1983).
     Excessive fertilization encourages thatch accumulation by increasing vegetative production,
but may also indirectly contribute to the problem by affecting decomposition processes. Nitrogen
fertilization commonly results in soil acidification (Pierre 1928) which may in turn inhibit microbial
activity (Starkey 1953, Martin and Beard 1975, Bridges 1983). Furthermore, the repellent nature of
NH4+ can reduce numbers of soil invertebrates, including microarthropods and nematodes, and
earthworms (Marshall 1977,  Edwards and  Lofty 1977).  Earthworms, in particular, are generally
sparse in acidic pasture and forest soils (Satchell 1977, Edwards and Lofty 1977). Several studies
(Starkey 1953, Engel and Alderfer 1967, Meinhold et al. 1973, Smith 1978, Potter et al. 1985) have
indicated correlation between high rates of fertilization and thatch accumulation, although this may
not  always  occur (Shearman  et al.  1980).  Potter  et  al.  (1985) sampled  earthworm  and
microarthropod populations  in Kentucky  bluegrass plots that had received  varying  rates  of
ammonium nitrate fertilizer (0 to 25 g N m-2) for seven years. Increasing the rate of fertilization
resulted in a significant decrease in soil and thatch pH and in exchangeable Ca and K, and caused
a significant  increase in thatch. These changes were accompanied by a significant (33 to  66%)
reduction in populations of earthworms and certain oribatid mites. Although thatch thickness was
correlated with decreased earthworm density and biomass, it is probable that other factors such
as increased plant growth and reduced microbial degradation also contributed to the relationship.
     Use of pesticides can also contribute to thatch development. For example, treatment with
certain fungicides may  reduce soil pH, which  can in  turn impair the activity of microorganisms
important to thatch degradation (Smiley and Craven 1978). Alternatively, fungicides may increase
rates of root and rhizome production, further contributing to thatch accumulation  (Smiley et al.
1985). Several investigators (Randell et al.  1972, Streu 1973, Turgeon et al.  1975) have reported
correlation between increased thatch and reduction in earthworm populations following  treatment
with certain insecticides or herbicides. Many pesticides commonly applied to turfgrass, including
benomyl, ethoprop, carbaryl, bendiocarb, and others, are toxic to earthworms (Ruppel and Laughlin
1977, Karnok 1980, Roberts and Dorough 1984, Potter, unpublished data).
     It is generally observed that thatch is rarely excessive where earthworms are abundant, but
until recently, the evidence that earthworms are important to thatch  degradation has been largely
correlative. If earthworms and other soil invertebrates are in fact critical to thatch degradation, then
careful consideration  should be given to any cultural practice  that might reduce their activity.
Experiments  currently in progress (Potter  and Powell,  unpublished data) appear to verify the
contribution of earthworms to thatch degradation in turf. Several hundred pre-weighed  pieces  of
intact Kentucky bluegrass thatch (8x10 cm; ca. 18 mm thick) were sewn into nylon mesh bags
having different sized openings (50 m, 1.2 mm, or 5 mm), and buried just under the surface of a
Kentucky bluegrass turf. The small, medium, and large mesh sizes were intended, respectively,  to
exclude all decomposers except microorganisms, to selectively exclude earthworms while admitting
smaller invertebrates, such  as mites,  or to admit all components of the soil fauna,  including
earthworms.  In a companion  experiment, thatch pieces in identical  large mesh bags were buried
in untreated plots, or in plots that had been treated with chlordane and carbofuran to eliminate
earthworms. Thatch pieces from each experiment were disinterred every 3-4 months to compare
rates of decomposition in the presence or absence  of soil invertebrates. Pieces were re-weighed,
analyzed for microbial activity and soil content,  and extracted in Tuligren funnels to determine the
invertebrate species present.  Dramatic differences were apparent in both experiments after only 3
months.  Without earthworms the structure and  composition  of  the  thatch  remained  nearly
unchanged; however, the pieces were broken apart and dispersed when earthworms were present.
The  most striking effect of earthworm activity was a significant increase in the amount of soil

incorporated into the thatch (Fig. 2). The effect of this natural process is very similar to that achieved
by core cultivation, a process by which soil is mechanically reincorporated back into the thatch
layer, and which is considered the best method of managing thatch (Beard 1973, Danneberger
1982). Rates of microbial respiration and loss of organic matter were found to be much greater for
thatch pieces that had been "worked" by earthworms than for those from which earthworms had
been physically or chemically excluded. Details of these experiments will be reported elsewhere.

                        ADDITIONAL CONSIDERATIONS
     Two other problems that may be encouraged by repeated pesticide usage in turfgrass are
acquired resistance of pests to insecticides or fungicides, and enhanced microbial degradation of
pesticide residues.  Acquired resistance  can become a problem when insecticides are applied
repeatedly  over a number of years. Acquired resistance has been documented for a number of
turfgrass pests, including webworms, chinch bugs, billbugs, greenbugs, and several species  of
white grubs (Tashiro 1982,  1987; Reinert 1982). Judicious use of insecticides, and alternation  of
treatments  with materials from different  chemical classes (e.g., organophosphate  followed by
carbamate) will help to prevent or delay this phenomenon.

     Enhanced microbial degradation occurs when pesticide residues are degraded more rapidly
than  usual by microorganisms. Enhanced  biodegradation apparently  occurs  as  a  result  of
microorganisms becoming adapted to a pesticide to the point of being able to use it as an energy
source (Forrest et al. 1981).  This phenomenon has been documented in soil for several insecticides,
including diazinon, carbofuran, fensulfothion, and isofenphos.

     Recent experiments (Niemczyk and Chapman 1987) indicate that this alarming pattern may
also occur in turf.  When isofenphos was applied  to golf course fairways that had  a history  of
isofenphos treatments, more than 90% of the insecticide degraded within three days. In contrast,
there was  practically  no degradation  in previously untreated fairways. Enhanced  microbial
degradation of  isofenphos residues in thatch appears to be the cause of at least some reported
cases of poor residual control of white grubs (Niemczyk and Chapman 1987). Even more disturbing
is the report that other insecticides, including diazinon, chlorpyrifos, carbaryl, and isazophos were
rapidly degraded  when applied to turfgrass that had  been previously treated with  isofenphos
(Niemczyk  and  Filary 1987).

     We choose not to here enter the debate concerning the potential acute and long-term chronic
effects of pesticide exposure to humans, pets, and wildlife, or the fate of pesticide residues  in the
urban environment, as these are complex biological, social, and political issues that have been
reviewed elsewhere (McEwen and  Stephenson 1979, National Research Council  1980, McEwen
and Madder 1986).

     The intent of this chapter is not to support or condemn pesticide use on turfgrass. Rather, our
 goal has been to review some of the ways that chemical applications can affect interactions among
 turf- inhabiting invertebrates, and to speculate on how these changes may alter the stability and
 resilience of the turfgrass ecosystem. There are  clearly certain  situations in which the use of
 pesticides is essential to the maintenance of quality turf. However, like human medicines, pesticide
 applications can have some adverse side-effects, and these must be weighed against the overall
 benefits that the treatment provides. The available evidence suggests that turfgrass is a complex
 system with  many  buffers.  However, we  are  only  beginning  to understand  the  roles  of
 microorganisms, earthworms, predators, and other invertebrates in maintaining this natural balance.
 It does appear that  pesticide or fertilizer applications  can  sometimes aggravate thatch or pest
 problems by interfering  with  the  activities  of beneficial  organisms,  or by encouraging  the
 development of acquired resistance  or enhanced microbial degradation. Awareness  of  these
 potential side-effects, together with additional research on basic interactions within the  turfgrass
 ecosystem may facilitate development  of more effective and  more environmentally-sound turfgrass
 management programs.

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Arnold, IB.; Potter, DA Environ. Entomol. 1987, 16,100-105.
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Bohart, P.M.; Hilgardia; 1947,17, 267-307.
Bridges, B.L "Thatch Control and Effects of Nitrogen on Certain Biological and Chemical Parameters in  Kentucky
        Bluegrass Turf". M.S. Thesis, Univ. of Kentucky, Lexington.
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Cockfield, S.D.; Potter, D.A. J. Econ. Entomol. 1984, 77,1542-1544.
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Kageyama, M.E. In "Advances in Turfgrass Entomology"; Niemczyk, H.D.; Joyner, B.G.; Eds.; Hammer Graphics: Piqua,
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Karnok, K. Lawn Care Ind.. 1980, 4,16.
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Luck, R.F.; Dahlsten, D.L.  Ecology 1975, 56, 893-904.
Marshall, V.G.; Commonwealth Bur. Soils Spec. Pub., 1977, no. 3.
McClure, M.S. Environ. Entomol. 1977, 6, 480-484.
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McEwen, F.L; Madder, D.J.; In "Advancesin Urban Pest Management"; Bennett, G.W.; Owens, J.M.; Eds.; Van Nostrand
        Reinhold: New York; 1986, pp. 25-50.
Meinhold, J.H.; Duble, R.L.; Weaver, R.W.; Holt, E.C.; Agron. J., 1973, 65, 833-835.
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        York; 1975,  pp. 235-273.
National Research Council. "Urban Pest Management". Report prepared  by the Committee on Urban Pest Management,
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Niemczyk, H.D. J. Econ. EntomoL; 1987; 80; 465-470.
Niemczyk, H.D.; Krueger, H.R.; Lawrence, K.O. Ohio Rep., 1977, 62, 26-28.
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Niemczyk, H.D.; Filary, Z. Proc. N.C.B. Meet., Entomol. Soc. Am.; 1987, (Abstr.).
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Pimentel, D.; Edwards, C.A. BioScience. 1982, 32, 595-600.
Potter, D.A. Am. Lawn Applic.; 1982, 3, 20-25.
Potter, D.A.; Bridges, B.L; Gordon, F.C. Agron. J. 1985, 77, 367-372.
Randell, R.J., Butler, J.D.; Hughes, T.D. HortScience, 1972, 7, 64-65.
Reinert, J.A. Ann. Entomol. Soc. Am. 1978, 71, 728-731.
Reinert, J. A. In "Advances in Turfgrass Entomology"; Niemczyk, H.D.; Joyner, B.D.; Eds. Hammer Graphics: Piqua, Ohio,
         1982, pp. 71-76.
 Roberts, B.L; Dorough,  H.W. Environ. Tox. Chem. 1984, 3, 67-78.
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 Shearman,  R.C.; Kinbacher,, E.J.; Riordan, T.P.; Steinegger, D.H.; HortScience, 1980, 15, 312-313.
 Short, D.E.; Reinert, J.A.; Atilano, R.A.  In "Advances in Turfgrass Entomology; Niemczyk, H.D.;  Joyner, B.G.; Eds.;
         Hammer Graphics: Piqua, Ohio,  1982, pp. 25-31.
 Shoulders, J.F.; Hall, J.R. Am. Lawn Applic. 1983, 4, 4-7.
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Ruppel, R.F.; Laughlin,  C.W. J. Kans. Ent. Soc.; 1977, 50,113-118.
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         1982, pp.  81-84.
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                                     FIGURE 1
    Impact of four turfgrass insecticides on spider populations in Kentucky bluegrass, based on
relative numbers captured in pitfall traps in treated and control plots. Replicated plots were treated
with surface sprays at label rates  in late  May. Similar reductions  occurred for other taxa  of
predaceous arthropods, although not all groups were equally affected. Reproduced with permission
from Cockfield and Potter (1983).
              O 80
              O 6O
              O 4O
A chlorpyrifos
+ bendiocarb
• trichlorfon
• isofenphos
  '      '	-4
                          WEEKS  POST-TREATMENT

                                      FIGURE 2
     Change in the mineral content of thatch pieces buried under Kentucky bluegrass turf for 12
 months. Samples depicted in upper graph had been buried in mesh bags having different sized
 openings to selectively admit or exclude certain components of the soil fauna (see text). Samples
 in lower graph were buried in identical large mesh bags in plots that were either untreated, or that
 had been treated with  pesticides  to eliminate earthworms. Data  represent percentage of final
 sample weight remaining after  incineration, and reflect mainly differences in the amount of soil
 incorporated into the samples by earthworms.
                 CD  4°

                 S  20

                 J  60
                           A  Large Mesh
                           O  Medium Mesh
                           •  Fine Mesh
A  With Earthworms

•  Without Earthworms

                                  TABLE 1
    Relative number of predatory arthropods captured in pitfall traps at Kentucky bluegrass sites
maintained under a commercial lawn care program ("high maintenance") or under minimal care ("low
maintenance"). Data are based on seasonal captures (22 March -18 October) from 4 institutional
lawns (1-4 ha each) of each type in Lexington, Kentucky. Adapted from Cockfield and Potter (1985).
                              Mean number trapped per site
                                 High               Low
  Taxon                      Maintenance     Maintenance
mm mm mm mm mmmmmmimtmm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm *•* mm mm mm mm mm mm mm <

   Carabidae                   24.8*             200.3

   Staphylinidae              774.0            1172.5


   Lycosidae                   29.3               38.8

   Erigonidae                 394.0*           1017.8

   Linyphiidae                 60.3*             183.0
^H ^_. ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^w ^^ ^^ ^^ ^^ ^^ ^^ ^^ •• MM <^» ^Ht ^^ «!• ^^ mm>mmi mm mm mm, mm tmm mm. ^mi mm, mm tmm^mt mm mmmmi mm mm MB mm mm mm mm mm mm mm «•» mm mm mm
*Significantly lower than corresponding mean  (P < 0.05)

                                      TABLE 2

       Mean percentage of sod webworm eggs eaten or carried off by predators in replicated plots
   of untreated Kentucky bluegrass compared to plots that had received a single surface application
   of chlorpyrifos at label rate. Based on cohorts of 500 total eggs placed in the field for 48 h at 1,3,
   or 5 weeks after the insecticide treatment. Reprinted with  permission from Cockfield and Potter
                       Percent missing  from
Weeks post-        Untreated        Treated
treatment             plots            plots              P levela
^"* ^^ ^^ ^* *** ^* ^™' ^* *^ ••» *^ <^* ^^ «^» ^» ^B «• ^M ^M •• *Bm ^^ ^B» ^^ ^M ^^ ^^ ^^ ^^ ^^ ^H» ^IB ^^^IV^IB ^^ «•» ^^ ^^ «•» ^|» ^^ ^^ «M «W «^ ^V ^^ ^^ ^^ ^^ ^W ^^ ^^ ^^ ^^ ^^ ^^ «• ^M ^» ^M «

    1                    37.7            0.9                P < 0.001

    3                    17.6            0.1                P < 0.05

    5                    75.4            61.3                P < 0.08

Probability of a greater t statistic, one-sided paired t test,

                   FOR LAWN CARE OPERATORS
                              James F. Wilkinson, Ph.D.
                   Director of Regulatory and Environmental Affairs
                    Professional Lawn Care Association of America
                                101 Buena Vista Drive
                              North Kingston, Rl 02852
    Pesticide applicators, particularly those applying pesticides in the urban environment, such
as lawn care operators (LCO's), today are confronted with a rapidly changing (and often adverse)
environment. Public perception of pesticides and pesticide applicators is at an all time low. Federal,
state and local regulation of pesticides increases almost daily. Environmental concerns from ground
water contamination to endangered species will continue to generate regulations to be imposed
on applicators for many years to come. And the non-agricultural user of pesticides, those applicators
using pesticides in the  urban setting  (lawns, trees) or for vegetation management (utilities,
rights-of-way) will face even stiffer rules and regulations. These uses have  a perceived lack of
"benefits".In addition, there is often the belief pesticides are not needed in the urban setting.

    This paper first will present legislative and regulatory concerns for the LCO both today and in
the future. The Professional Lawn Care Association of America (PLCAA) is currently involved with
most of these issues since the issues will undoubtedly have a major impact on the way in which
pesticides are used (or not used) in the future. Safety, health, certification and training issues will
all play an increasing role and require increased attention from the LCO.

    Next, the paper will review the need for LCO's to begin to help formulate reasoned pesticide
public policy. This will involve cooperation with other pesticide applicator groups, decision makers
(legislators and regulators), and environmental activists. LCO's will need to further incorporate IPM
and other techniques into their operations to reduce pesticide use and use pesticides more safely.
Otherwise, future regulations may jeopardize the very existence of the lawn care industry itself.


    The American public's perception of pesticides and  toxic chemicals today, created generally
by the media, environmental groups and  a few, but highly effective antipesticide activists, is at an
all time low. Here are the subjects of just a  few of the stories which the  public hears almost on a
daily basis:
      pesticide residues on food
      groundwater contamination
      farm workers exposed to pesticides
      death of Navy Lt. Prior after playing golf
      2,4-D, cancer and Kansas farmers
      data gaps, chronic effects of pesticides unknown
      allergies/sensitivities to pesticides
      dioxins, agent orange, Love Canal

     It's no wonder that the public is concerned and feels the way it does about pesticides after a
steady diet  of such stories. These stories,  especially when highly publicized by environmental
groups such as the National Coalition Against the Misuse of  Pesticides,  Sierra Club, Audubon
Society,  National Wildlife  Federation,  and Environmental Defense Fund, strike a nerve with the
public. Concern over pesticide use is heightened when pesticides are being used right in their own
back yards for lawn care.
     All of this has created a number  of broadly defined issues facing the pesticide user industry
in general, and the LCO in particular. These begin with the public demanding  their right-to-know
more about pesticide use and health and safety, and could end  up with serious impairments to the
way LCO's currently conduct their business.


     The public's right-to-know  has become  an important issue among anti-pesticide  groups and
government officials. Communication of this right-to-know is taking many different forms  as the issue
arises in various locations around the country.
     Prenotification of pesticide applications has been proposed  in many areas and has already
been adopted  in  some localities.  Proposals  often include notification  of not only the LCO's
customers,  but neighbors as well.  LCO's are strongly opposed to notification of everyone  in the
immediate areas of an application. They believe it is unjustified, and that it would add tremendously
to their cost of doing business.
     Some states (Rl, MA, MD,  NY) have adopted regulations requiring prenotification  of lawn and
tree pesticide applications as requested by customers and  neighbors. This system seems to be
working well, since only a small minority of people actually request prenotification so that it is not
overly burdensome to the  LCO.
     Posting after lawn  and tree care  applications is required in at least  half a dozen  states, and
more are sure to follow. In this  case, strong  industry input into  the drafting of the  regulations has
so far led to the  use of signs only at the time of application (as opposed to before the application).
Many groups are in favor of "pre"posting (putting up signs one to two days before the application),
and should this type of posting become law, applicator costs will significantly increase.
     Central registries of pesticide sensitive or allergic individuals are gaining favor in some areas.
Pennsylvania and Maryland, as well as some local communities, have established registries for
individuals with medical evidence of an allergy or sensitivity to pesticides. The names of individuals
on the registry are then shared with applicators to allow them to prenotify allergic individuals of
impending applications.  Industry's reaction to this system has been positive, with a high degree of
compliance  by individual  companies.  The actual  number of people placing their names on the
registry has thus far been low.

     Health  and safety information is frequently required to be passed along to customers, and this
trend is expected to continue in more states. This information generally involves post application
safety precautions, but in some  cases  labels and MSDS's must be made available.
     The newly passed  federal  Community Right-to-Know Law will also  require certain pesticide
applicators to provide material information to local fire departments and other emergency personnel.
     Local jurisdiction over pesticides is often  an issue which arises out of local right-to-know
concerns. Federal legislation as well as  legislation in many states often prohibits  political entities
below the state  level from regulating  the use of pesticides.  Numerous applicator alliances have

challenged the right of local governments to regulate pesticides (Wauconda, IL; Prince Georges
County, MD), and in most  cases courts have upheld the right of only the federal  and  state
government to regulate pesticides. With over 88,000 political entities below state level in the U S
LCO's clearly have a concern over the chaos which would be created if local governments were
given authority to regulate pesticides.

                          PUBLIC HEALTH AND SAFETY

     Public concern over the health effects of exposure to pesticides will continue to generate future
regulations. Chronic risks from low levels of long term exposure, particularly in food residues and
drinking water are a major concern.  Dislodgeable residues resulting in potential human exposure
to pesticides after lawn care applications is receiving considerable attention and has been one
justification for requiring lawn care posting.

     A recent GAO report alleging inadequate EPA testing of most pesticides will surely speed  up
the federal reregistration of many  pesticides to bring them up to current registration standards. At
the same time, some  states have  lost confidence in the  EPA's ability to  adequately regulate
pesticides and protect the  public. Thus, some states (CA, MA) will begin  to require their own
registration data. Both of these developments will surely lead to higher pesticide costs and product
loss as manufacturers conclude that the economics of a product simply does not justify continued

     The public also is increasingly hearing the question of risk/benefit analysis on pesticides used
non-agriculturally. Why, some ask, take any risk whatsoever simply to have a green lawn or to
control vegetation that could be controlled mechanically? Non-agricultural users of pesticides have
not done a good job of communicating the benefits of pesticides.

                       EMPLOYEE HEALTH AND SAFETY

     The health and safety of applicators regularly using pesticides is receiving increasing attention.
Proposed and enacted legislation and regulation in this area alone will add huge costs to LCO
operations in the future. Consider the following examples:
     • OSHA'S Hazard Communication Standard requiring health and safety information to
       be shared with employees;
     • a newly proposed  EPA worker protection standard requiring health monitoring and
       extensive personal protection equipment;
     • strengthened  certification and training requirements in most states and the adoption
       of federal minimum standards for certification and training;
     • a narrowly defeated Senate bill which would have required extensive monitoring of the
       health of employees occupational^ exposed to toxic chemicals;
     • a newly implemented regulation  requiring drivers carrying hazardous substances to
       carry commercial driver's licenses;
     • proposed changes  in pesticide labeling which should make them more readable for
       applicators, yet create labels which will contain more detailed information than ever.

     Employee health issues will undoubtedly increase the cost of doing business, and at the same
time make it increasingly difficult to find and train employees in an increasingly tight labor market.


                          ENVIRONMENTAL CONCERNS

     Numerous concerns for the environment will place further scrutiny on all pesticide applicators,
 not just LCO's. Concern for the impact of pesticides on endangered species is leading to areas
 where specific pesticides simply will not be allowed. Wildlife concerns have recently led to the
 banning of diazinon on golf courses and sod farms. Problems with disposal of pesticide containers
 and wastes (RCRA, Superfund) have led to volumes of regulation.

     The  "granddaddy" environmental  concern for the  next decade,  however, is  groundwater
 contamination. As the EPA concludes its current survey of wells around the country, and more trace
 amounts of pesticides are found in wells, more and more public misunderstanding, fear, regulation
 and product loss and restriction are bound to impact pesticide applicators. LCO's can expect to
 encounter more questions and concerns about their use of pesticides around public and private
 sources of drinking water.
                                   LEGAL ISSUES

     Several legal issues are currently being debated as well. While some of these wouldn't seem
 to have an immediate impact on the LCO, their long term impacts could be immense:

     • The 1988 amendments to FIFRA (FIFRA 88) significantly expand ERA'S authority to
       regulate recall, storage, transportation, and disposal of pesticides. The Agency must
       exercise this authority by the study of all aspects of these issues, consultation with
       affected and interested parties, and issuing of requirements for storage, transportation,
       or disposal of a suspended or cancelled pesticide or its container, rinsates, or other
       materials which may be contaminated with such a pesticide. These findings must be
       submitted to Congress by December 1990. The new regulations will affect end users
       to the extent that they are subject to recall procedures. Details of reporting requirements
       will be announced in the Federal Register when they are developed.

     • Under FIFRA 88 end users such as pesticide applicators will generally be indemnified
       against the costs of disposing of cancelled or suspended pesticides.

     • Applicator liability on issues such as ground water contamination is another issue that
       was debated but not resolved in FIFRA 88. Farm groups are currently proposing that
       their members be exempt from liability should they be able to show they used a pesticide
       in accordance with all label directions. If this exemption is allowed, should it be extended
       to the non-agricultural user as well?

     •  Private right of action, or the ability of a citizen to bring suit against an applicator for
       pesticide misuse, another issue being debated,  could change our thoughts on liability

     •  Local regulation of pesticides continues to be debated  at the federal level as well as
       within many states. Although applicators have won a few battles in the area, the war
       is far from over. All pesticide users should easily understand the chaos that would be
       created should the more than  88,000 local government entities in the United  States
       be given the authority to regulate pesticides.



    LCO's need to be more aware of the public's concerns over pesticides. Whether or not our use
of pesticides creates a hazard is often not the issue. The issue sometimes becomes the fact that
the public perceives a hazardl We must be willing to put ourselves in their shoes and imagine how
we would feel if we believed pesticides were a threat.

    Industry's response to many pesticide issues in the past has not been adequate. It is time
industry becomes more proactive in terms of defending the legitimate and safe use of pesticides.
The public must be made more aware of  pesticides'  benefits; regulators and extension people
must be better educated on the professionalism which already exists within the lawn care industry;
and all of us must work towards reasonable  pesticide public policy. Increasing regulation is headed
our way, and we must work hard to keep it reasonable.

    The impact of lawn chemicals on ground water is a good example of where to start to educate
decision makers and the media. Research underway at numerous universities is finding that lawn
chemicals do NOT have  the same potential  to contaminate groundwater as pesticides applied
agriculturally. It is important that decision makers understand this when developing groundwater
protection strategies.

    Alliances of pesticide users at the local,  state and national levels need to be  formed and to
become actively involved in pesticide policy formation. A few state alliances, as well as the national
Pesticide Public Policy Foundation, are already working toward this goal, but the job is immense
and much more work is needed. The opposition, the anti-pesticide forces, are well organized and
funded, and they network extremely well. Pesticide users need to rise up to face their challenge.

    A major goal of the Pesticide Public Policy Foundation is to bring together an alliance of all
national urban pesticide user groups (lawn,  tree, pest control, landscape, golf, right-of-way) and to
foster the  formation and development of state-wide pesticide user alliances. Applicator alliances
must be formed rapidly and in as many states as possible to allow applicators to be heard on the
many important issues facing them today.

    At  the same time,  LCO's need to do all they can  to get their own house in order. Applicator
training  requires the highest priority,  and operations must be run squeaky clean. Applicators also
need  to understand that  they must  adapt  to many changes on the horizon such as IPM, new
application equipment,  and new products which will change forever the  pesticide application
business. LCO's definitely use less pesticide today than in the past, and this trend will continue.

    The Professional Lawn Care Association of America is directing an increasing amount of its
resources to  regulatory and legislative concerns.  PLCAA's goal is to protect the right of their
members to apply pesticides safely, yet at the same time ensure adequate safeguards to protect
employees, customers and the environment.


                          WITH PESTICIDE USE
                        IN THE URBAN SECTOR
                                    Anne R. Leslie
                         U.S. Environmental Protection Agency
                             Office of Pesticide Programs
                          Field Operations Division (H7506C)
                                   401 M Street SW
                                Washington, DC 20460
    The stage is set for spring in the Washington, D.C. metropoiitan area. Rows of forsythia paint
a golden backdrop to the ribbons of highway. The silhouettes of bare fruit tree branches glow with
color and then disappear in soft clouds of pink or white blossoms. The birds and squirrels compete
less for seeds around the feeder and more for each other's attention. Homeowners spend warm
days pruning, raking, digging, planting and fertilizing, as they try to realize the fragile dream of a
colorful flower garden framed by a deep green lawn.

    Contained within these suburban gardens is a population of life forms which are indicted  for
their ability to interfere with the achievement of the dream. My neighbor's yard of wheat colored
zoysia (whose golden color is prized in Japan)  is punctuated with green clumps of wild garlic. This
plant is not as obvious amid my lawn of mixed fescue and bluegrass, cool season grasses which
green up earlier than zoysia or bermuda. Yesterday I dug some up to  put in my salad as I pulled
out unwanted honeysuckle that was moving from its firm foothold on an old wire fence to take over
the yard, strangling a tree on the way.

    In the lawn, a patch of bare earth piled up in mounds attests to activity of ants, and my neighbor
worries at seeing a rat in his garage. The pest control company arrives to set out bait-the neighbor
carries a contract with them to treat for termites, ants and roaches.

    My yard has a patch of wild mustard, whose time of flowering is already past, and  the seed
heads float above the lawn. Henbit displays tiny purple flowers from a patch of soil the grass
disdained to cover. Should we call a lawn care service, or visit the nursery or hardware store  for
some broad-leaf weed killer to clean up the lawn and get rid of these  pests-or is there another way?

    The appearance of all these life forms is part of the natural ecology. They have found a
favorable niche to live in, and they are not concerned that it is the same niche we live in.

    I would gladly pay for some sound  advice  on the alternatives for my half acre. Is a good lawn
the best choice? Will the henbit and mustard retreat to form a meadow transition to the neighboring
woods? I need to know what effort this will require.
    What might I expect over a period of time if I just keep adding organic matter, adjusting the
soil pH as needed, and overseeding with a grass variety that is adapted to my site? The beneficial
spiders, earthworms and the bacteria in the grass thatch can then continue their roles in the system
without the effects of pesticide. And if a damaging level of a pest such as  the Japanese beetle
appears, I might put my faith in introduction of their natural enemy, an entomophagous nematode.

     Hand digging of unwanted plants may be enough to control a lot my size. But if my yard were
 larger, it would be prohibitively labor intensive. What if I  let the grass grow to three inches instead
 of one and one-half? The dandelions will have their spring show and be choked out later by the
 healthy grass. Crabgrass is an annual. It has left its dead skeletons in patches where its seed can
 sprout anew. But I can tip the scales in favor of a chosen variety of grass that may grow vigorously
 and inhibit the crabgrass seedlings by shading them out.

     The decisions I have to make are similar to those confronting many homeowners in the United
 States. Because some  homeowners lack time to  manage their own  lawns and lack first-hand
 agronomic experience, choosing a lawn care service seems very attractive. Yet some sectors of
 society are objecting to the choices made by others, particularly when a contracted service impinges
 on a neighbor's property.

                   Problems Related to Pesticide Regulation

     Environmental and citizen groups have collected information on pesticide use practices and
 combined that information with potential health and environmental hazards of individual pesticides.
 The public's concern over small amounts of chemicals in ground water is compounded by the lack
 of real data on long-term health effects of low level exposure. Detection is now better than ever
 because of the improved analytical  methods developed by chemists in recent years. Testing for
 health effects lags far behind technically. It is an expensive and long-term project, and the regulatory
 process that requires and evaluates such studies is complicated and slow moving.

     The federal government gives the states and local communities the ultimate responsibility to
 control the way registered pesticides are used. Local governments may decide to notify the public
 of pesticide use by posting  areas being treated, and they draw up requirements for certification of
 applicators. However, there are limitations on what these controls can accomplish in the urban area,
 given the following facts:

     Most  pesticides  applied to  home  lawns are not restricted to use only by a certified
     applicator, and posting of private residences is not required.

     Large rural areas are being rapidly converted to  urban land uses, which pose new
     problems  that may require regulation.  The  regulatory agencies  do not  have the
     manpower for enforcement of proper pesticide use by private citizens.

     Turf is not considered  an agricultural  crop  in some States, and, therefore, does not
     receive as much research funding to determine the  effects of its management on the
     environment.  However, it carries a definite economic value, which is used to justify the
     application of pesticides in its management, even though a dollar value for an aesthetic
     product is difficult to determine.

     The very real problem of resistance to pesticides is appearing in  insects, as shown in
     the chapter by Metcalf; in weeds as detailed  in a  paper presented by LeBaron  (ACS
     Symposium  Series, in press,  1988), and  in fungus as noted  in  the  chapter  by
     Dernoeden. Resistance buildup leads to use of increasing amounts of pesticide on turf,
    just as on agricultural crops.

                  Problems Related to Conflicts in Land Use

    Conflict exists between people willing to pay for pesticides to achieve high quality turf on their
lawns and people not wanting to have pesticides on their property, or even nearby. And conflicts
exist over other kinds of land development.

    Golf courses are a very visible expanse of highly managed turf. Projections of the increase in
the golfing  population by the National Golf Foundation (Golf Projections 2000, Golf Summit '86
Research Presentations, October, 1986) call for the opening of one new course per day until the
year 2000.  This represents a conservative 2% increase in this recreational land use. People who
have experienced hypersensitivity to pesticides raise objections based on the potential for drift
Environmentalists fight the conversion of wilderness areas and impacts of land development on
endangered species; cities blame the courses  for pollution of their water supplies.

           Studies on Water Pollution by Pesticides Used on Turf

    For the most part, both sides argue from a minimal data base. Studies on groundwater pollution
in natural watersheds, with one exception, have not been carried out. EPA's well  water survey
includes only agricultural land. The Cape Cod study carried out by EPA showed positive levels of
nitrogen and traces of pesticides. No similar sampling studies have been run in less permeable soils
than the sandy soil of the Cape. The studies by Gold and Sullivan, reported in chapter 13, include
the most targeted and complete  information  we have seen to date on  waterborne transfer of
fertilizers on home lawns. Controlled studies on pesticides in runoff from turfgrass plots are reported
by Welterlen in chapter 14. Studies by Watschke at Penn State University, Niemczyk at Ohio State
University,  and Petrovic at Cornell University substantiate the ability of thick turf to prevent or
minimize pesticide transfer to water. These studies are cited in the above chapters.
    More significantly, ground and surface water pollution from runoff of paved areas may be the
largest urban source, since any chemical sprayed  near or spilled on paving materials has great
potential to be carried to the watershed. Although pesticides are not deliberately applied in these
areas, they may arrive there carried by trucks,  along with other chemicals such as gasoline, oil, dry
cleaning fluids, disinfectants, and structural pesticides. In short, anything that  is spilled during
transport or accidental application.  Many chemicals  are not  removed at most existing water
treatment facilities.
    Few published studies on  water pollution via runoff from paved areas have been  reported,
although some companies are running determinations.
    The greatest source of water pollution is application of chemicals to agricultural land. Concerns
over contamination  of groundwater by pesticides applied to turfgrass are usually based on the
agricultural groundwater studies. Leaching through  bare soil is much greater than through grass
and thatch, as shown in the chapter by Welterlen. Agricultural use of pesticides and fertilizers is still
much higher on a per acre basis than on golf  courses, although limited areas of golf courses may
use a higher rate. Agriculture employs restricted pesticides which are generally not used on urban

              Direct Health Effects to Applicators and  Residents

    Pesticides registered  for use on turfgrass and  ornamentals  carry labels indicating  proper
handling, protective clothing requirements and disposal instructions. These are based on studies
required by EPA and carried out by the registrant. Restricted use pesticides are available only to

certified applicators, whether commercial or private. Certification is awarded on evidence that the
applicator knows how to handle the material.
     Although it is believed  that current  regulations  adequately  protect the applicator,  such
regulations may not protect a resident of the treated site. Because nonagricultural use of these
pesticides has increased, EPA's Office of Pesticide Programs is re-examining current requirements
for studies of dislodgeable residues. There is potential for exposure to residents "reentering"the
lawn  after  treatment.  These residents may include a  highly  vulnerable segment  of the
population-either directly, as with children playing on the lawn or indirectly with pets or applicator
clothing coming into the household.

                 Landowners' Rights versus Society Benefits:
                           Need for Land Use  Planning

     Health and environmental effects of turf pesticides are often  cited in disputes over urban
development. But the concerns have not always led to productive solutions. The societal issues are
outside the scope of this book. However turfgrass managers who practice  more sophisticated
pesticide use through an IPM program will be making a positive step  towards resolution.
     Cities grappling with such issues need comparative  data on the impact of all land development
alternatives to decide on the land use of greatest benefit to society. All residents must keep in  mind
that urbanization is taking place regardless of individual preference, and wise planning needs to
be done early to avoid the problems many cities now face.

         Limitations  of Pesticides and the Need for Realistic Goals

     At the other end of the scale, homeowners are often led to expect they can obtain golf course
quality turf solely through  greater use of pesticides. And  because they lack agronomic experience,
they do not use cultural practices that can support reasonably  high quality lawns. With increasing
demands for perfect turf, the cost of chemical use and maintenance of a lawn escalates significantly.
     Just as a cockroach inside the home incites much  greater urge for chemical control than do
most outdoor "bugs,"a dandelion on a home lawn may incite a desire for pesticide use that would
not be expressed for the same pest density in a park.

     In a National  Park Service project, stands of grass with different  levels  of weed infestation
were to be evaluated by people to determine their perception of the  grass quality. No satisfactory
scale has yet been established.

     Societal conflicts  have  evolved from  urbanization  of  former  agricultural  land.  Where
development leads to  increased  pesticide use, land use  planners need to  consider long-term
consequences. An IPM  program can  help greatly  to reduce these potential  consequences.
Education of the public in basic  agronomic practices and environmental fate of chemicals can
contribute  greatly  to their intelligent decision-making  for land use,  management goals and
conservation  of resources. The remainder of this book is devoted to examining some of the best
methods and putting them together in a concerted IPM program.

             SECTION II
               Benefits of an
          Integrated Pest Management
      Approach to Turfgrass and Ornamentals


                       AND IMPLEMENTATION:
                                 W. M. Brown, Jr.
                                  W. Cranshaw
                             Colorado State University
                              Fort Collins, CO 80523
                               C. Rasmussen-Dykes
                      Jefferson County Cooperative Extension
                                 Golden, CO 80401
     Integrated pest management (IPM) programs are underway for many agricultural commodities.
 In contrast, few IPM programs are established in urban environments. The reasons for the lack of
 functional urban IPM programs vary, but two significant reasons emerge:

     • the lack of technology and programs to address the wide variety of plants, cultural
      practices and pests encountered in the urban habitat;

     • the lack of consistent research and development support for urban programs in pest

     This is paradoxical, considering that in 1982 a national Extension Committee on Policy (ECOP)
 reported that 7.5% of the total pesticide used in the United States  is used by homeowners. An
 additional 19.4% is used by urban government and industry (7). Thus, a total of almost 27% of the
 pesticides used in the United States are used in our densest population areas, and by predominantly
 untrained pesticide users. Concern over pesticide use has triggered right-to-know and pesticide
 posting ordinances in several communities in recent years. In Colorado, the city of Boulder recently
 voted to establish a pre- and post- pesticide posting ordinance covering lawn spraying. Frequently
 anti-pesticide advocates promote "IPM" as  a blanket alternative to pesticide use without actually
 being fully aware of the lack of a research and implementation base in urban IPM. Therefore, a
 critical need  exists for comprehensive national urban  IPM  education,  research  and program
 development. A pilot urban IPM educational and field program has been developed in Colorado and
 is described in the following pages.

                          DISEASE MANAGEMENT

    Under good cultural practices, Colorado has few turf and ornamental disease problems. The
problems encountered  are frequently in stress situations resulting from  unrealistic design,  poor
management, intensive use (i.e.,  golf courses with night watering and heavy traffic), home lawns
with poor site preparation, high  nitrogen and excessive pesticide  applications or ornamentals
planted in inappropriate sites.


     An exception are the Pythium blight diseases caused by E aphanidermatum. E. ultimum. E
myriotylum. and E torulcsum. all reported pathogens on turfgrass (15) that have been associated
with disease outbreaks in Colorado (13,14).

     Little work  has been  done on  biological control of turf diseases.  Trials  using  a known
mycoparasite of Pythium spp., a benomyl tolerant mutant of Trichoderma harzianum (T95) (3,4,5)
and a systemic fungicide specific for  Pythiaceous fungi, metalaxyl, were carried  out at  Colorado
State University and at field  sites in Colorado. Tests were conducted on all the above Pythium spp.
found associated with blighted turf in Colorado (13,14).

     Each Pythium  spp. was parasitized by T harzianum in vitro in much the same manner as
described by Chet et al. (6). Trichoderma hyphae coiled  around Pythium hyphae  and  the latter
collapsed (Fig. 1). Low concentrations (25-200 ppm) of metalaxyl significantly retarded mycelial
growth of Pythium spp. (Fig. 2). Equal concentrations of metalaxyl did not affect mycelial growth
and spore production of T harzianum. although higher concentrations (275-2500 ppm) did (Figs.
3,4). Trichoderma  spores  produced  on  media at 750 ppm  metalaxyl  when  streaked  onto
non-amended PDA media were viable.

     Additional studies showed that other  pesticides frequently used in turf disease management
(benomyl, chloroneb, diazinon,  Trimec, phenyl-mercuric  acetate+thiram and iprodione) did not
significantly affect the population of T.  harzianum (Fig. 5)(13).

     Work at Colorado State University by Ahmad and Baker (1) has demonstrated that rhizosphere
competent mutants are more efficient in colonizing and subsequently protecting roots from infection.
In  addition to suppression  of disease causing organisms, T95  also has demonstrated growth
enhancement properties in  bluegrass in  the  absence of known pathogenic  organisms, Fig 6
(5,13,14,17).  The mechanism responsible for  growth enhancement  by  Trichoderma is  not fully
understood (17). The attraction of a biological control agent that is also compatible with fungicides
and provides growth enhancement even in the absence of disease is exciting and more research
must be initiated in this area.

     A fluorescent pseudomonad, used as a  biocontrol agent, was effective in control of take-all of
Kentucky bluegrass, caused by Gaeumanoyces graminis.  Figure 7 shows the effect on bluegrass
growth in pots infested with the take-all fungus. Similar effects of fluorescent pseudomonads on
wheat take-all organism, Gaumanomyces tritici have  been reported by Baker, Cook and others (2,
18, 19).

     While more work must  be done to develop fully integrated Pythium blight or other turf disease
control programs with combined chemical and biological components,  the prospect is  exciting.
These  components must now be field-tested using  commercial  turf management practices, and
appropriate ways must be developed to deliver Trichoderma or other biocontrol organisms.

                              INSECT MANAGEMENT

     Many of the insect and mite problems common in urban plantings in Colorado are unique to
the region and have not been studied in depth. Lack of information on life history of these pests,
their management and injury potential  has significantly contributed to misunderstandings regarding
appropriate controls and the damage assessments. This lack of information  has resulted in
excessive or  inappropriate  pesticide  usage habits  that  are  incompatible with  IPM strategies.
Consequently, a fundamental research effort at Colorado State University (C.S.U.) has been to
improve our understanding of regional pest species biology and habits and  to convey this information
through Cooperative Extension outlets.

    Concurrently, insect management research studies have been conducted to develop effective
IPM technologies. Summaries of recent efforts and future needs are outlined below:

     Major emphasis has been to develop insect parasitic nematodes as biological control agents
for thatch and soil infesting insect turf pests. White grubs in the genera Cyclocephala. Phyllophaga.
and Polyphylla have been successfully controlled  in our field trials at rates of control equivalent or
sometimes superior to most standard insecticide treatments. In particular, the nematode genus
Heterorhabditis (heliothidis. 'H.p. 88') has been effective in white grub control. Nematodes in the
more commonly commercially available genera  Neoaplectana (primarily N, carpocapsae) have
been less effective for white grub control but have shown potential against other common turf pests
such as sod webworms, cutworms, and billbugs (8).

     Effectiveness of nematodes against soil insects has been shown by other researchers (8,16)
to be influenced by factors such as soil type and moisture. In C.S.U. studies the importance of thatch
as a barrier to nematode movement has been quantified.  Of all the insect parasitic nematodes
studied, only a small percentage of them (8-17%) were able to penetrate through a 1.5 cm thatch
barrier layer. The ability of different strains and species to penetrate thatch varied; Heterorhabditis
proved the species most inhibited by thatch. Trying to "flush"nematodes through thatch with varying
water volumes was ineffective. It is obvious that thatch management will be important in effective
use of insect parasitic nematodes as well as insecticides for soil insect control. Fortunately, insect
parasitic nematodes do not adversely affect earthworms, the most important organisms involved
in organic matter breakdown in turf. Impacts of nematodes  on other non-target pest species are in

     Insect parasitic nematodes have also been screened for compatibility with various  turfgrass
management chemicals. Soaps and wetting  agents appear fully  compatible with  nematode
applications as are most fertilizers (16). Fungicides, with the notable exception of the mercurials,
show no toxic effects to nematodes. However, mercurial fungicides are devastating to nematodes
and prior use of  these compounds may preclude  adequate survival of insect parasitic nematodes
at a turf site. Tested insecticides (11) show a range of effects on insect parasitic nematodes with
the toxicity  potential  ranging chlorpyrifos, bendiocarb, carbaryl,  diazinon.  However, nematode
species sensitivity to various compounds  varies. For example  chlorpyrifos is  highly toxic to
Heterorhabditis but only moderately toxic to Neoaplectana: carbaryl only showed toxic effects to

                                         TABLE 1

 Summarized results of white grub control with insect parasitic nematodes and Lawn Aerator Sandals
 in Colorado State University trials, 1986-1987.

       Trial Location                       Target Pest          Treatment
       % Control
       Lamar, CO
       57                               Phyllophage.          Diazinon 14G
       55                               Polyphylla           Lawn Aerator Sandals
       48                               H. heliothidis

       33                             N. carpocapsae

       Pueblo, CO
       94                              Cyclocephala          Oftanol 2
       47                             N. carpocapsae
       45                               H.-H.P.88"

       Grand Junction, CO
       0                               Cyclocephala
                                      N. carpocapsae

     Simple cultural controls also appear  to have potential in managing regional turf problems. A
 1986 study evaluated the use of a spiked sandal, sold under the trade name "Lawn Aerator Sandal"
for white grub control. Merely walking across plots with this product achieved a level of control
 (approximately 50%)  comparable to that  of the insecticide (diazinon) standard (Table  1). Other
studies are demonstrating that adequate winter watering, a neglected turf maintenance procedure
 in the arid West, can greatly limit turf injury by clover mites and sod webworms.

Woody plants.

     Spraying trees  and shrubs has become a particularly  visible  and  controversial use  of
 insecticides in  urban areas. Technologies to limit these treatments  have proceeded along the
following approaches.

     Expanded trials developing the use of soil injected systemic insecticides was emphasized in
 1987. These treatments involve the use of specialized equipment that rapidly injects the insecticides
into  the soil for subsequent root  uptake,  thus  avoiding drift and  many non-target problems.
Oxydemetonmethyl (Metasystox-R) is fully labelled for this use and has shown promising levels of
control against aphids, psyllids and mites (Table 2).  Unfortunately  control of leaf chewing insects
(beetle larvae, tip moths, gall midges) with this product has been erratic. An alternative soil systemic
treatment with great potential is  dimethoate. Dimethoate is effective against a very wide spectrum
of woody plant pests.  Expanded use of this material is pending labelling developments.

                                          TABLE 2
Summary of Colorado State University control trial results using soil applied systemic insecticides,
       Target Pest

       Honeylocust pod gall midge

       Honeylocust pod gall midge

       Honeylocust spider mite

       Honeylocust plant bug

       Honeylocust rust mite

       Honeysuckle aphid

       Ash leaf curl aphid

       Pinyon spindle gall midge

       Pinyon tip moth

       Hackberry nipple gall

       Hackberry bud gall

       Elm leaf beetle













Degree of Control













      Various "softlnsecticide treatments also show potential for greatly expanded use in landscape
 plant care. Insecticidal soaps are routinely incorporated into CSU trials and have shown fair to good
 potential for  control of spider mites, eriophyid mites, plant  bugs, leafhoppers,  and some aphids.
 More recently, interest has focused on the horticultural oils for summer foliage uses. These refined
 specialty oils appear to be greatly  under-utilized at present. Researchers  in other areas  of the
 country have shown an exceptional level of effectiveness of these products against young scales
 and whiteflies in foliar applications.  C.S.U. trials  established efficacy against eriophyid mites and
 spider mites.

      Elm leaf beetle treatment, the most common insecticide application made to trees in southern
 Colorado, demonstrates how several potential alternatives  may be developed. Use of insecticide
 spot treatment to trunk bands was shown in  1984 studies to  be highly effective at controlling larvae
 as they move to the tree base to pupate.  A number of community spray  programs have since
 successfully  adopted area-wide  trunk band applications  with a  dramatic reduction in insecticide
 usage and drift. In addition, new control products  are in advanced  development. The biological
 control Bacillus thuringiensis 'San Diego' shows activity against elm leaf beetle larvae and may be
 marketed in 1989.  Summer spray oils also were effective in preliminary  1987 studies.

                           EDUCATION AND TRAINING
    A major thrust of the Colorado urban  IPM program is to expand information sources and
delivery. This recognizes that lack of information on proper pest management methods leads to
inappropriate pesticide use. Instruction in diagnosis, damage evaluation, timing of treatments, and
effective pesticide  alternatives can produce reductions in inappropriate preventive or "revenge"
treatments. IPM education was especially given a high priority in the 1981 ECOP report on urban
IPM (7). Additionally, increasing public awareness of ecological implications of pesticide use can
promote more thoughtful considerations prior to and during urban pesticide applications.

    Expanded  IPM education is receiving major emphasis in the Colorado program. Colorado
Cooperative Extension education activities are targeting three distinct audiences: turf and landscape
maintenance professionals, homeowners, and youth.

    Colorado State University IPM specialists carry on extensive workshops, field days and field
experiment/demonstrations with parks and  recreation, professional lawn care  and  golf course
personnel. Over 1,000 turf professionals receive IPM training and updating each year. An additional
500-600 commercial landscapers, nurserymen, urban foresters and other urban pest management
professionals also  benefit from IPM training sessions. In  addition to  actual organized training,
Colorado State entomologists and plant pathologists routinely offer informal on-site training through
cooperative field trials, demonstrations, and visits.

    A major emphasis has been made to update and develop new materials on regional urban
insect management problems. In particular, publications outlining the  proper use of  insecticidal
soaps, Bacillus thuringiensis. pheromones and spray oils for regional problems have been popular
and distributed widely. Aides for identification of beneficial insect species and references in proper
use of commercially available biological controls have also been well received.

    For example,  an atypical Extension publication drawing considerable interest from youth and
adult  audiences promotes "butterfly gardening". Implied in "butterfly gardening" is the careful use of
pesticides,  further assisting  in improving pesticide use  habits  among urban audiences.  By
emphasizing  and valuing an overlooked beneficial group of common insects this publication has
directly assisted overall IPM efforts.

    The Cooperative Extension Master Gardener program promotes appropriate IPM strategies
for urban situations. Over 10,000 volunteer Master Gardeners have received IPM training and serve
as Cooperative Extension paraprofessionals in Colorado urban communities (Fig. 8). For example,
in 1986 in Boulder County, Master Gardeners fielded over 6,704 client queries. In Jefferson County
(western Denver Metro area),  106  Master Gardener volunteers worked over 3,000 hours.  Their
impact in providing educational service to the wider community is outstanding (Table 3). Many of
the Master Gardeners stay with the program and serve as volunteer leaders or in other,  more
advanced program capacities.

                                       TABLE 3

                 Jefferson County* 1986 Master Gardener Accomplishments

                          Master Gardener's Trained/Used        106

                          Volunteer Hours Worked             3-000+
                          Plant Specimens Examined           1-082
                          Telephone Queries Answered        14,000+

                           * West Denver, CO, and adjacent foothill rural areas.
    CSU IPM staff developed a special youth educational program, "THE BUG SHOW" using large
insect and vegetable hand puppets (Fig 9). Use of large hand puppets have increased elementary
school students attention and awareness (10).  A pilot program consisting of a 15-minute  skit
followed by a question and answer period was begun in 1987. Advanced Master Gardeners (those
who have received two or more years of in-depth  Master Gardener training in horticulture and IPM)
were  trained as puppeteers. CSU Cooperative Extension  staff  and Master Gardeners have
presented the pilot program to 350 youth (pre-school through third grade) in the Denver Metro area.
This program gives youth an introduction to  biology, biological control and pesticide safety. After
the program, teachers and students use CSU prepared activity booklets as supplemental in-class
or at-home study material. Under development is  a follow-up video presenting selected information
on biology, pesticide safety, and IPM; each teacher will be provided a copy for further class use and
     Information dissemination systems using technical sheets, radio shows, weekly newsletters,
and a special Cooperative Extension pre-recorded phone Teletips weekly Urban Pest Alert are all
operational. The Teletips system uses three-minute pre-recorded tapes to provide current pest
occurrence and management updates. Pest  Alert tapes are updated weekly or more frequently if

                             FUTURE  IMPLICATIONS

    While there is a critical need for development  and implementation of urban IPM, major problems
    There is very little plant pest research in  urban IPM. Without a strong commodity support base,
little financial support  is available for urban  IPM  research. Minimal available funds are generally
attached to chemical  research.  Thus, biological and  cultural  control approaches receive less
    There is a government trend to  decrease Cooperative  Extension  in the cities. This  is
demonstrated in both federal budgets (i.e., Reagan Administration FY 87) and in many state budgets
such as Colorado's 1987 and 1988, budgets in which decreases have specifically targeted urban
programs. The critical nature of pest management education and  research in urban IPM and its
components  must gain recognition,  if environmentally sensitive urban  programs  are  to  be
    Present laws and confusion between various governmental agencies as to testing of biological
control organisms in the environment must be clarified; provisions must be made for testing. Much

of the work to be accomplished in development of biological control is done and will be done by
universities and public agencies. To date there is not enough public funding for this essential
research and development.
     Technology is available that can be adapted to urban IPM programs in turf and ornamentals.
Much more is needed to provide a base for comprehensive urban IPM success. Without adequate
funding, recognition and general education, successful implementation of IPM strategies to urban
situations and the resultant use of pesticide alternatives will not be realized. This has long range,
negative implications for both urban and farm populations.

                                       LITERATURE CITED
1.  Ahmad, U.S., and R. Baker. 1987. Competitive saprophytic ability and cellulolytic activity of rhizosphere-competent
        mutants of Trichoderma harzianum. Phytopath. 77:358-362.

2.  Baker, K.F. and R.J. Cook. 1982. Biological control of plant pathogens. Amer. Phytopath. Soc., St. Paul, MN. 433 pp.

3.  Baker, Ralph. 1985. Biological control of plant pathogens: definitions. Pages 25-39 in: Biological Control in Agricultural
        IPM Systems. M.A. Hoy and D.C. Herzog, eds. Academic Press, NY. 600 pp.

4.  	. 1986. Biological control: an overview. Canadian Journal of Plant Pathology 8:218-221.

5.  	. 1987. Enhancing the activity of biological control agents. Pages 1-17 from Innovative Approaches to
        Plant Disease Control. I. Chet, ed. Wiley and Sons, NY.

6.  Chet, I., G.E. Harman,  and R.  Baker. 1981. Trichoderma hamatum: Its hyphal interactions with Rhizoctonia solani
        andPythium spp. Microb. Ecol. 7:29-38.

7.  Evans, Burton  R., ed. 1981. Urban Integrated Pest Management Programs for State Cooperative Extension Services.
        A Report for the Extension Committee on Organization and Policy. Cooperative Extension, Univ.  of Georgia,
        Athens, Georgia, 30602, 20 pp.

8.  Gaugler, R. 1981. Biological control potential of Neoaplectana nematodes. J. Nematol. 13:241-249.

9.  Georgis, R. and G.O. Poinar. 1983. Effect of soil texture on the distribution and infectivity of Neoaplectana carpocapsae
        (Nematoda: Steinernematidae). J. Nematol.  15:308-

10. Gilfoyle,  E.M., and J.A. Gliner. 1985. Attitudes  toward handicapped children: Impact of  an educational program.
        Physiol. and Occupational Therapy in Pediatrics 5:27-41. Haworth Press, NY.

11. Hara, A.H. and J.K. Kaya. 1982. Effects of selected insecticides and nematicides on the in vitro development of the
        entomogenous nematode, Neoaplectana carpocapsae. J. Nematol. 14:486-491.

12. Rao, P.S.P., P.K. Das,  and G.Padhi. 1975. Note on compatibility of DD-136 (Neoaplectana dutkyi). an insect parasitic
        nematode with some insecticides and fertilizers. Indian J. Agric. Sci. 45:275-277.

13. Rasmussen-Dykes, C.  1983. Developing an integrated control program for Pythium blight of turfgrass. M. Sc. Thesis.
        Colo. State Univ.,  Fort Collins, CO. 73pp.

14. 	,  and W.M. Brown, Jr.. 1982.  Integrated control of Pythium blight on turf using metalaxyl and
        Trichoderma hamatum. Phytopath. 72:975.

15. Saladini,  J.L.. 1979. Cool versus warm season Pythium blight and other related Pythium problems. Pages 37-39 in:
        Advances in Turfgrass Pathology. P.O. Larsen and B.G. Joyner, eds. Harcourt  Brace Jovanovich,  Inc. Duluth,
        MN.  197pp.

16. Schroeder, W.J. and J.B. Beavers. 1987. Movement of entomogenous nematodes of the families Heterorhabditidae
        and Steinernematidae in soil. J. Nematol. 19:257-259.

17. Windham, M.T., Y. Elad, and R. Baker. 1986. A mechanism for increased plant growth induced by Trichoderma spp.
        Phytopath. 76:518-521.

18. Wong, P.T.W., and R. Baker. 1984. Suppression of wheat Take-all and Ophiobolus patch fluorescent pseudomonads
        from  a Fusarium-suppressive soil. Soil Biol. Biochem. 16:397-403.

19. 	t c. Rasmussen-Dykes, I.E. Perotti and W. M. Brown, Jr. 1982. Occurrence of Ophiobolus patch of
        turf in Colorado. Phytopath. 72:976.

                                 LIST OF FIGURES
Figure 1.  Trichoderma harzianum isolate T95 coiled around Pythium spp. showing the collapsed
          parasitized condition of the latter.

Figure 2.  Effect of metalaxyl at varying concentrations on mycelial growth of Pythium spp.

Figure 3.  Effect  of  metalaxyl at varying concentrations  on myelial growth  of  Trichoderma
          harzianum isolate T95.

Figure 4.  Effect of metalaxyl at  varying concentrations on  spore  production of  Trichoderma
          harzianum isolate T95.

Figure 5.  Recovery of Trichoderma harzianum isolate T95 after various fungicide treatments.

Figure 6.  Kentucky bluegrass at left untreated, plants at right treated with Trichoderma harzianum
          isolate T95.

Figure 7.  Kentucky bluegrass plants in pots from left to right, pots infested with Gaeumannomyces
          graminis. G. graminis plus a fluorescent pseudomonad, and uninfested check.

Figure 8.  Colorado master gardener class observing solar treatment of soil trials.

Figure 9.  Cindy Rasmussen-Dykes with children and bug puppets used for childrens education
          IPM programs.

                                     FIGURE 1

Trichoderma harzianum isolate T95 coiled around Pythium spp. showing the collapsed parasitized
condition of the latter.

                              FIGURE 2

 Effect of metalaxyl at varying concentrations on mycelial growth of Pythium spp.
? 25

• r *
. r . «
*»"* *



                              25        50       100
                           Metalaxyl (jug/ml)

                            FIGURE 3

Effect of metalaxyl at varying concentrations on myelial growth of Trichoderma harzianum isolate
            25   50   100  150  187 375  625  750 1250 2500
                      Metalaxyl  (jug/ml)

                            FIGURE 4

Effect of metalaxyl at varying concentrations on spore production of Trichoderma harzianum isolate
    x  12
    £  8
I    I    I    I     I    I     III
              i    iiii
                               i     •     •
       0    25   50  100  150   187 375 625 750 1250 2500
                      Metalaxyl (jug/ml)

                                FIGURE 5

Recovery of Trichoderma harzianum isolate T95 after various fungicide treatments.


            Q  25


            10  20

                                     FIGURE 6
Kentucky bluegrass at left untreated, plants at right treated with Trichoderma harzianum isolate T95.

                                    FIGURE 7

Kentucky bluegrass plants in pots from left to right, pots infested with Gaeumannomyces graminis.
(L graminis plus a fluorescent pseudomonad, and uninfested check.

                                    FIGURE 8
Colorado master gardener class observing solar treatment of soil trials.

                                   FIGURE 9
Cindy Rasmussen-Dykes with children and bug puppets used for childrens education IPM programs.



              Michael J. Raupp, Mildred F. Smith and John A. Davidson
                           Department of Entomology
                            University of Maryland
                            College Park, MD 20742
    A landscape plant management pilot program was initiated in 1978 by extension specialists
in the Department of Entomology, in cooperation with a county agent and a community of suburban
Maryland homeowners. The objectives of the program were twofold. The first objective was to
demonstrate the feasibility of the integrated pest management approach for managing landscape
plants. As part of this approach,  participating homeowners received regular monitoring of pest
activity by a trained scout. The scout prepared a report that was reviewed by extension personnel.
Management recommendations were sent to each cooperator via a weekly or biweekly newsletter.
In addition to specific management recommendations, homeowners received timely extension
literature on the life cycles and control of insects and diseases, cultural plant care, pest identification
and proper pesticide use. As an educational program, the project provided homeowners with
information that would allow them to deal with their plant problems more effectively. The second
objective was to quantify changes in knowledge, attitudes, skills, and practices brought about by
the program.

    The program expanded from about 20 homeowners in the initial year (1978)  to 100
homeowners  in its final year (1982). At the conclusion of the 1982 program, a comprehensive
evaluation was conducted. The program was evaluated by two methods, a survey of program
participants and a group comparison between participants and their non-participating neighbors.
Analyses were based on the 59 participants and 47 of their non-participating neighbors. Both survey
techniques indicated substantial changes in knowledge, attitudes, skills, practices, and end results.
Table 1 summarizes some of the changes detected by the survey of program participants.

                                      TABLE 1
            Changes Brought About by an IPM Program for Landscape Plants
                                                        Response (%)
   	Impact	    Increase    No  Change    Decrease

   Identify  ornamental  plants                 58            42             0
   Inspect plants for problems                58            40             2
   Recognize agents causing problems          75            25             0
   Select the correct chemical control       75            25             0
   Apply the chemical at the proper time     66            32             2
   Use controls other than chemicals          53            47             0
   Substitute alternatives for chemicals     45            52             3
   Knowledge of cultural plant care          78            22             0
   Deal  effectively with plant problems      83            15             2
     In addition to the changes summarized in Table 1, other changes were quantified. Ninety-seven
 percent of participants believed that the information received would be useful in future years and
 81% thought this approach would save money on pest control in the long run (the average estimated
 savings was $53 per year). Furthermore, 93% felt the program was worthwhile and 98% believe it,
 or a similar one, should be conducted in the future. Program participants said that they followed
 extension recommendations about 71% of the time and were satisfied with their results 81% of the

     In the area of pesticide application, participants  and their non-participating neighbors were
 asked to select the best means of controlling aphids. Possible  choices  included insecticide,
 fungicide, miticide, and soapy water sprays and ladybird beetles. Responses of participants differed
 significantly from those of non-participants. The majority of non-participants  selected insecticides
 as the control method of choice while cooperators selected insecticidal soaps most frequently. This
 difference undoubtedly resulted because participants were informed that insecticidal soaps provided
 good control  of aphids and were an environmentally preferred alternative  to insecticides.
 Homeowners were asked the same question  regarding the control of mites. Non-participating
 homeowners  chose  insecticides as  the  preferred  control  tactic while participants  selected
 insecticidal soaps and miticides most frequently. This difference  is especially important  because
 many insecticides provide little, or no, control of mites. An additional finding of interest was  that 15%
 of the non-participants said that they had received helpful pest management information from
 neighbors who had participated in the program.

     The final phase of homeowner program evaluation was conducted in 1985 when approximately
330  former  program  participants were sent  a questionnaire  through the  mail.  Ninety-eight
homeowners returned the questionnaire. Of these,  71% indicated that they  still used information
from the program. This compares very favorably with other surveys of information sources used by
homeowners. In 1979, Barrows et al. found that only 17% of gardeners surveyed used information
from the local Cooperative Extension Service. A national survey of homeowners conducted by the
Nursery Marketing Council  (1983)  revealed  only  about 16% using agents,  universities, and

governments as a primary information source. Several uses of information are summarized in Table

                                      TABLE 2

                  Information Use by Former IPM Program Participants
        Recognize cause  of problem
        Decide if control is needed
        Select proper  control
        Apply controls at proper time
        Use pesticides safely
Continue  to Use

Never Use

 In addition to these results, 48% of those responding believed this information had helped prevent
 plants from dying.

     Community managers and grounds maintenance supervisors face problems similar to those
 of homeowners with respect to the types of pests affecting their landscape plants. A demonstration
 project was conducted within a city of 27,000 people in 1983 and 1984. The demonstration project
 in 1983 placed 354 acres inhabited by 1,661 residents under IPM management. In  1984, the
 program was expanded to 476 acres, occupied by 3,844 people. Over the two years of the program,
 pesticide sprays were reduced by an average of 83% and the overall cost associated with pest
 management was reduced by 22% on the average. In 1985, the program was transferred to a private
 consultant employed  by the city. The program expanded to seven communities.  Environmental
 impact data is unavailable for the  program conducted  by the consultant; however,  economic
 information indicates that costs continued  to be reduced under the IPM approach  (Table 3). The
 average total cost reduction resulting from the adoption of IPM ranged from $4.8 to 21.7/acre. The
 mean savings realized was $12.9/acre + 3.99 (standard error).

                                      TABLE 3

      Economic Assessment of Traditional and IPM Programs in Three Communities

   Community        	Cost	   Acres   Cost Reductions  $/Acre

                    1982a   1983b  1984b  1985C           1983     1984      1985

      1              2895    784     822    210     131    16.1     15.8      20.5
      2             3750    1663    2986    420      56    37.3     13.6      59.5
      3             1325    510     401      0      17    47.9     54.4      77.9
   Pesticide Total 7970    2957    4209    630     204    24.6     18.4      36.0
       Labor Total    0    2505    2779   2920
             Total 7970    5462    6988   3550            12.3      4.8      21.7

      a.   1982  — Traditional management program, including cover spray,
                   no monitoring.
      b.   1983,  1984 — IPM management program conducted  by Cooperative
                         Extension Service  as a demonstration.
      c.   1985  — IPM management program conducted by private consultant.
     The success of the landscape plant management programs for homeowners and communities
 prompted extension  specialists  in entomology  to  undertake a demonstration  project with a
 commercial arborist. The objective of this program was to demonstrate that an arborist could provide
 the same approach for managing pests as did the extension based  IPM programs. This was a critical
 step in transferring technology to the commercial sector.

     The program demonstrated the feasibility of the IPM approach conducted in the commercial
 sector. Furthermore, it demonstrated that an arborist could reduce unnecessary pesticide use by
 94% while maintaining a high level of customer satisfaction with the program. Seventy-eight percent
 of the clients said they preferred the IPM approach to traditional cover sprays.

     Part of the effort to continue the transfer of IPM technology to the commercial sector has been
 an intensive training program. One component of this  training has been a technical conference held
 each winter at the University of Maryland. This interdisciplinary conference, called the  Interstate
 Ornamental Plant Management Conference, features nationally recognized plant management
 experts from  the  disciplines of entomology,  pathology, agronomy, weed science, botany,
 horticulture, and the green industry. In its first three years, this conference has provided training to
 more than 700 businessmen, government workers, and extension personnel. Ninety-six percent of
 the attendees at the 1985 conference rated the overall quality of the 20 presentations as satisfactory
 or excellent.

    Other training activities include in-depth workshops conducted over several days during the
winters of 1984  and  1985.  These workshops focused on interdisciplinary approaches of pest
management  and were limited to  approximately 30 participants each year. To determine how IPM
information was  being  implemented  by former workshop attendees, a telephone survey was
conducted during the winter of 1986. The study group consisted of former program participants and
a group of Maryland arborists selected at random.  Both groups were asked questions designed to

reveal their pest management practices. One of the major impacts of the IPM approach is a reduction
in unnecessary pesticide use. When asked if their pesticide spraying had declined in the last ten
years, 83% of program participants were spraying less. Sixty-seven percent of non-participating
arborists were also spraying less. Not only did program participants spray less, but the materials
sprayed were more environmentally acceptable. Pesticides may be categorized according to toxicity
and environmental persistence. Pesticides such as horticultural oils, insecticidal soaps, and the
insect pathogen Bacillus thuringiensis (Bt) are considered biorational insecticides due to their low
toxicity  to vertebrates and short environmental persistance. Insecticides  used by workshop
attendees were compared  to  ones  used by arborists that  had  not  participated in  workshops.
Arborists that had received IPM training were significantly more likely to use biorational  insecticides
(Table 4).  Furthermore, former program participants were the only ones to suggest non-chemical
controls for pests.
                                       TABLE 4
              Control Tactics Used by Arborists for Controlling Insect Pests



       Spider Mites
Attended IPM




                                                     Control Method (%)




Biorational    Organic






     A second critical component of any IPM program for landscape plants is the regular inspection
of the plants for problems caused by pests or improper culture. Eighty-five percent of the firms that
attended workshops employed at least  one person whose  primary  responsibility was plant
inspection. This contrasts with arborists that had not attended workshops. Only half of these firms
employed plant  inspectors. To be effective, monitoring must be performed on a regular, short-term
basis. This means a minimum of ten,  or more, visits per growing season. A comparison of  the
frequency of inspections by program participants and non-participants revealed that  57% of  the
participating arborists conduct ten, or more,  regular inspections compared  to only 20% of  the
arborists that did not attend IPM workshops.
     In summary,  the demonstration programs have had the following results. First, they have
conclusively demonstrated the  feasibility of  implementing  IPM  technologies in non-traditional
settings, such as landscapes. Moreover, they have demonstrated that persons other than farmers,
or farm consultants,  can implement  IPM programs. This group includes homeowners, grounds
maintenance personnel, and commercial arborists. As educational activities, these programs have

succeeded in changing knowledge, attitudes, skills, and practices of information recipients. These
changes have had the following economic and environmental impacts. They have reduced the cost
of pest control.  The documented  savings  in the community-based IPM  programs  averaged
$12.9/acre. More important than  the economic impacts are the environmental ones. Documented
reductions in pesticide use in the  arborist demonstration program averaged 73 gallons (dilute)/acre.
These studies clearly indicate that IPM technologies have tremendous potential benefits for urban

                             LITERATURE CITED
Barrows, E.M., J.S. DeFilippo, and M. Tavallali, 1983.Urban community gardener knowledge of arthropods in vegetable
      gardens in Washington, D.C.. lo: G.W. Frankie and C.S. Koehler (eds) Urban Entomology: Interdisciplinary
      Perspectives, pp. 107-126

Nursery Marketing Council, 1983. Nursery Consumer Profile. 230 Southern Bldg., Washington, D.C. 20005.


                                 Zachary Grant
                     Formerly Manager of Government Relations
                 Golf Course Superintendents Association of America
                              1617 St. Andrews Drive
                               Lawrence, KS 66046
    Building a golf course in the late 1980's involves challenges beyond architecture, engineering,
finances and the demands of the game. In many states, developers of a course must also overcome
forbidding legal and regulatory barriers related to zoning, planning and environmental protection.
    One of the most challenging of those regulatory obstacles is Vermont's Act 250 development
law, which requires that proposed developments meet a series of ten separate tests to obtain a
land use permit. These tests, administered by an independent environmental commission, range
from effect on water quality to infrastructure demands to aesthetic value.
    For the past four years, Act 250 compliance has been the aim of developers of the proposed
Sherman Hollow golf course, planned for construction near Burlington, Vermont. Along the way, the
Sherman  Hollow management  team has demonstrated exemplary concern for environmental
interests, in spite of often burdensome and frustrating  regulatory requirements.
    Over the past four years, vocal opponents of the project repeatedly intervened to stall the
progress of approval for Sherman Hollow. Using slogans such as  "Keep Sherman Hollow", the
protesters at one time appeared capable of bringing the development to a halt. Today, through a
series of positive and progressive steps, much of the opposition to Sherman Hollow has subsided.
However the Sherman Hollow permit was denied by the State Act 250 Commission. The Vermont
Pesticide Advisory Council is now drawing up a comprehensive protocol for golf course permitting,
and the Sherman Hollow case has been granted a new hearing.
    A key component of the Sherman Hollow response to Act 250 inquiries was development of
an integrated pest management (IPM) plan to govern the use of pesticides on the proposed golf
course. Thought to be the first of its kind in the United States, it was hoped that this IPM plan could
serve as a model for the golf industry in its efforts to contribute ever more  effectively to the
enhancement and protection of our natural environment. Meanwhile Cornell University Extension
Service has been developing a detailed IPM manual for golf courses in the northeast that embodies
ail the concepts put forward in the Sherman Hollow plan. The manual should be available in the fall
of 1989.
    This essay explores the general nature and advantages of IPM to the golf course turf industry
and outlines some of the specific features of the Sherman Hollow IPM plan.


    Integrated pest management (IPM) has been defined in various ways by various authors, which
has led to some confusion about the precise  meaning of the term.  From the perspective of golf
course turf management, one enlightening definition was provided by Victor A. Gibeault and others
of the University of California, Riverside.


    They suggest that "IPMis defined as multiple tactics used in a compatible manner in order to
maintain pest populations below levels that cause economic or unacceptable aesthetic injury without
posing a hazard to humans, domestic animals, or other non-target life forms."

    The decision-making process inherent within this definition involves setting up tolerance levels
for pest populations, monitoring  turf areas  for pest incidence, maintaining accurate  records of
monitoring data and taking appropriate actions with regard to the information collected through

    An important point to note is that IPM is not itself a tactic for controlling pests, but rather it is
a system  for understanding various strategies and tactics of pest control. It serves  to guide the
pest manager in recognizing and selecting  among various tactics. Further, it requires that such
selections be hazard-efficient.

    One  of the objectives of IPM  is to use chemicals less, but it  is a misconception that IPM
programs  always replace  chemical control. Rather,  IPM encourages the pest manager to use
chemicals more wisely, which can mean less often. In a study of tree care reported by Dr. Michael
J. Raupp, an entomologist at the  University of Maryland, pesticide use was reduced by more than
90% when IPM was utilized. Studies of household pest control have shown pesticide use reductions
of 80% and more in controlling cockroaches.

    To implement the  IPM approach, superintendents must be prepared to establish thresholds
for unacceptable economic or aesthetic injury based upon some reliable system of measurement.
Before resorting to the use of any chemical pesticide, it should be established by actual monitoring
of the turf that injury thresholds - or action  levels related to such thresholds - will be exceeded
unless chemicals are used. Until these thresholds are  crossed, use of alternative methods should
be attempted as feasible.

     Because  IPM is inherently site  specific,  explicit thresholds and the means of measuring injury
cannot  be standardized for  the golf industry. However, this should  not deter  experienced
professionals from drawing upon their best judgement in making such determinations.

     Sheila  Daar,  IPM consultant  and Executive Director  of the Biointegral   Resource Center,
explains "golfers and superintendents at different courses will have different tolerance levels for turf
injury. And differing maintenance regimes will result in different degrees of injury from the  same
number of pests. The setting of injury thresholds just isn't subject to uniform standards."

                      SHERMAN HOLLOW:   THE SETTING

    Sherman Hollow is in Huntington, Vermont, 18 miles southeast of Burlington, and 20 minutes
from the Burlington International Airport. It is within 30 minutes of the Stowe, Sugarbush and Bolton
Valley ski  areas and 25 minutes from Lake Champlain.

    Sherman Hollow occupies 1,200  acres of land in the foothills of the Green Mountains. The
golf course is part of an overall development plan that will include a 70 room inn, conference facilities,
indoor tennis courts, a complete sport fitness center, 72 luxury townhouses, a live theatre, a chapel,
and 40 kilometers of cross-country ski trails.

    The development will be arranged in a clustered "village" occupying  only  20 acres. The golf
course will be built on an adjacent 120 acres.

    Sherman  Hollow, Inc. President Paul Truax and his family have lived on Sherman Hollow land
for many years. Paul and his wife Colleen purchased the core farm in 1961 with an eye toward

recreational development. Their residency is an important factor in the environmental sensitivity
exhibited throughout the development.

     "We've left a lot of land open, clustered the village and set a limit on the size of the project,"
noted Truax, "We want to make a profit, but life-style is important. After all, we live here."

The Golf Course

     Sherman Hollow's  golf course promises to be one of the finest in Vermont. Designed by
architect Charles Ankrom and golfer Raymond Floyd, the par-72 layout will measure 6,849 yards.

     Ankrom already has a number of fine layouts to his credit, including the TPC course at Monte
Carlo and the Tower Club and Crane Creek in Martin Downs, Florida.

     In designing Sherman Hollow, Ankrom recognized the need for a solid environmental design.
 Even with the natural plateaus and terracing of the property, the course drops vertically more than
300 feet from start to finish.

     From a design standpoint, Ankrom indicated that his key environmental concerns included
erosion control - especially during clearing and construction --and good water management.

     "We are  doing a variety of things to control erosion," Ankrom  said. "The layout parallels the
natural terrain, creating terraces to reduce runoff. We've used birming, water retention areas, natural
watersheds -- the works. We have no interest in soil leaving the property, so we've been very careful."

     An extensive erosion control plan, detailing every square foot of the construction  site, has
been submitted to the Act 250 commission.

     Ankrom  also noted that good  water management would play an essential role in  pest
management. An extensive irrigation  and drainage system is planned to interface with a series of
five lakes.
     Floyd, who counts the 1986 U.S. Open crown among his five major tour victories, is consulting
designer for the project. He will bring to the project his expertise as a well-travelled golf professional.
     Commenting on  the environmental  effect  of  the project,  Floyd referred favorably to the
proposed IPM plan: "We play golf to  enjoy and enhance  our environment. If we can provide top
quality playing conditions with  reduced chemical applications, that is going to be good for the game.
The specific pest control plan is outside my area of expertise but, as a player, I appreciate the
philosophy behind it."

Pesticide Use Plan

     The protracted battle for Act 250 approval has involved dozens of public hearings concerning
the proposed golf course. The Sherman Hollow management team sought assistance from a variety
of outside authorities, including a hydrogeologist, toxicologist, agronomist, environmental scientists
and others.
     Late in  the  spring of 1987, Sherman  Hollow Superintendent  Garry  N. Crothers, CGCS,
contacted GCSAA's office of government relations for assistance. Through GCSAA contacts, a
working relationship between Sherman Hollow and the U.S. Environmental Protection Agency (EPA)
was established.
     Anne Leslie, of EPA's Integrated Pest Management Unit, and Unit Chief Diana Home, had
indicated to GCSAA representatives earlier that year that they were looking for golf courses to serve
as IPM demonstration  sites. Given Sherman Hollow's interests and needs, it was determined that
a possible compromise could be arranged.


     By early  summer, discussions between  Sherman Hollow and  the  EPA  had solidified an
agreement in principle to implement a comprehensive  IPM plan. Leslie appeared at a local permit
hearing in Vermont to discuss the proposal. Shortly there-after, the local Green Mountain Audubon
Society withdrew its objections to the  golf course plan, a move that "stunned  opponents of the
project", according to a report in the Burlington Free Press.

     In  a letter to Truax, Craig S. Sharf, chairman of the Green Mountain  Audubon Conservation
Committee, wrote that "the information you presented to us has satisfied our concerns and provided
us with  the assurance  we felt is necessary."

     Sharf said in a recent interview that some local  Audubon members oppose any development
whatsoever at Sherman  Hollow. Others, including  himself,  see some  form of development as
inevitable.  In that context, he sees the golf course as an "acceptable"alternative.

     On July 29, Sherman Hollow representatives travelled to Washington, D.C., along with Kenneth
E. Bannister of the Vermont Department of Health, to meet with EPA representatives, and observers
from the staff  of  U.S. Senator  Patrick  Leahy, a Vermont Democrat and chairman of the  Senate
Committee on Agriculture, Nutrition and  Forestry. This meeting produced  a formal outline of the
agreement to participate in an IPM demonstration project.

     During the day long meeting, it was agreed  that the overall goal of the IPM project was to
reduce  dependency on pesticides while maintaining  a  high quality golf course. The EPA supports
the project to  promote IPM for turfgrass  and to demonstrate that good results  can be achieved
when the best IPM practiceaare put to use.

     "Weare pleased to be able to take a leadership role in protecting the future of the environment,"
Truax  said. "We are  particularly pleased to have the benefit  of EPA's  research and  input in
implementing this plan. GCSAA has been instrumental in securing our good relationship with  EPA
and other interested parties."

     Leslie, of the EPA, pointed out that the Sherman Hollow  IPM project is not expected to be an
experiment per se, but rather a joining of the very best of various individual techniques to see  how
well they work within a comprehensive IPM approach.

     "We will be looking for good preventive maintenance, such as selecting well  adapted varieties
of grass, proper irrigation,  fertilization, aerification, mowing and so forth," Leslie said. "And we will
recommend biological controls and other alternatives as advisable. Monitoring, record keeping and
setting thresholds will be the  key to chemical treatments."

                                 IPM ADVANTAGES

     A dedicated IPM program can help superintendents do a better job of managing turf pests and
using various means of pest control -- including chemicals - as widely as possible. For those  who
take IPM seriously, the rewards can be great. In the case of  Sherman Hollow, IPM may spell the
difference between having a golf course and none at all, if the opposition of environmentalists and
concerns of regulators can thus be resolved.

Better Control

     To  individual superintendents, equally  important advantages may result from adoption of an
IPM approach. By encouraging the natural predators of turfgrass pests, for example, more effective
control can be achieved. Further, the superintendent will not inherit the work of beneficial predators
that might be killed off  by the  overuse of non-selective chemical pesticides.


     Dr. Don Short, extension entomologist at the University of Florida, recently reported that, in a
three year study in south and central Florida, spot treatment with pesticides and weekly monitoring
of the turf resulted in good control of chinch bugs and webworms.

     "This is primarily due to the fact that we are not killing off beneficial organisms that may be
providing more control than pesticides," Short concluded.

     Where overdependence on chemical controls has substantially reduced non-target beneficials,
the stage is set for a dramatic resurgence of the unwanted pest. This is similar to the unchecked
expansion of exotic pests in areas where they have no natural enemies, such as introduction of the
mole cricket from South America in the early 1900's.

Avoiding Pest Resistance

     Recent experience with various control failures  illustrates the logical extension of this boom
and bust cycle. Where dependency on chemical solutions is great, pest populations can develop
resistance to pesticides.

     Selection pressures are exerted by pesticide use, because genetically superior pests, which
are less susceptible to the pesticide, will survive the application and pass their superiority to the
next generation. With each successive treatment, greater resistance is encouraged. Eventually, the
pesticide itself will no longer provide effective control.

     James F. Moore, mid-continent director of the USGA Green Section, observed this same trend
in a recent issue of the USGA Green Section Record.

     "Combine excessive chemical use with improper turf grass selection and superintendents find
it necessary to make more and more pesticide applications a year," Moore noted. "Onthese courses,
it is only a matter of time until resistant organisms develop or the turf overdoses on the chemicals."

Healthy Turf

     Moore's use of the word  "overdose"is well chosen. Similar to a person addicted to drugs, a
golf course that is over-dependent on chemicals may be addicted to pesticides. In both  cases,
chemicals become necessary for short term survival but counterproductive to overall health.

     Used wisely, both drugs and pesticides can have medicinal or therapeutic value. A seasoned
physician addresses illness by  adjusting diet,  exercise, environment  and various treatment
interventions,  including  Pharmaceuticals. Likewise, a good superintendent maintains  healthy turf
through appropriate cultural practices, fertilization, irrigation and various pest controls, including
chemical pesticides.

     Experienced superintendents realize that misuse of chemical pesticides can itself increase
turf stress.  Each additional application  carries the small, but significant,  risk of mishaps or
misapplications  that may radically degrade turf quality.  These can include improper mixing or
calibration, accidental use of the wrong chemical, spillage or equipment failure -- the list goes on.

     USGA's Moore sums up the idea well  by noting  that chemicals "are not a substitute for good
agronomics. By far the best chemical pest control programs are those that are as simple as possible."

Safety and Cost Factors

     Minimizing hazards to humans, domestic animals and other non-target life forms is a part of
IPM by definition. This does not universally translate into reduced use of chemicals, but often fewer
applications do result.


     For every application avoided, the associated human and environmental risks are avoided.
Risks may also be reduced by use of chemicals that are more highly selective in attacking only the
target pest, or by more selective applications, such as spot treatments.
     The direct cost savings of  reduced pesticide use also can be substantial when the price of
single applications may be several thousand dollars.
     The independence and judgement of individual superintendents considering an IPM alternative
is essential in this respect. Because the use of pesticides is a cost factor in golf course maintenance,
a superintendent has no monetary incentive to apply chemicals unnecessarily. Every treatment
avoided is money in the bank.
     The trade-off between resource  intensive chemical controls and labor intensive alternatives
may involve transitional costs. However, actual cost savings have been demonstrated in some pilot
     "Our experience has consistently shown the long  term  costs of IPM are less than with
preventative chemical spray routines," says Daar.


     One of the most important advantages of integrated pest management is that IPM recognizes
the agronomic insight and management skill of the superintendent. The  turf manager's judgement
in balancing aesthetic,  environmental, agricultural and human factors is the key to effective IPM.
The level of responsibility and professionalism involved exceeds sheer dependency on  chemical
     Further, IPM is important from the perspective of good stewardship. Superintendents have a
powerful interest in the  long term viability of the land they manage. The challenge to do everything
possible to preserve the integrity and productivity of the land logically  includes a  personal
commitment to IPM.
     "A superintendent  with the  vision to effectively administer such a system is obviously a very
valuable asset to his employer," concludes  GCSAA director William Roberts, CGCS. "It is, very
simply, the smart way to manage pest problems."
A Word of Caution

     Cultural  techniques, such as proper  aerification, thatch control, good drainage and careful
irrigation have long been used by golf course superintendents to maintain healthy turf.
     "We have been using IPM practices," notes Dr. Leon Lucas, Professor of Plant Pathology at
North Carolina State University,  "but many haven't called them 'IPM'".

     Yet, there is a difference between the use of practices consistent with an IPM approach and
actual adoption of IPM as a system of pest control.

     Because of the positive public image associated with minimizing pesticide use, there is some
temptation to appropriate the language and trappings of IPM prematurely, without a commitment
to meaningful changes  in behavior. Doing so reduces IPM to a hollow shell surrounding the same
old methods of pest control.

     "Even where essentially benign techniques are being used," Daar said, "if there is no monitoring
program, no record keeping, no known tolerance level -- then there is no IPM."

     The danger is that IPM will lose its credibility and appeal as  an  alternative to  increasingly
unpopular traditional  methods. Where there is even the suspicion  that IPM has been  used to


whitewash continued overdependence on chemical pesticides, its value in resolving the emotional
debate over environmental issues will be lost.

     To preserve the genuine advantages of integrated pest management, it is important that the
approach be understood and implemented with sincere appreciation for its intrinsic merit. In that
vein, the work of progressive  projects, such as Sherman Hollow, should  be encouraged and

The Bottom Line
     Ultimately, the Sherman Hollow IPM plan represents a very creative and progressive response
 to an increasingly common -- and  increasingly complex - set of problems facing proposed golf
 course developments. By exhibiting an extraordinary level of professionalism and environmental
 concern, Sherman Hollow has set an important example for others in the golf industry.

     As the Selectmen of the Town  of Huntington testified during Act 250 hearings, issuing permits
 for Sherman Hollow would allow "flexibility in efforts to preserve the delicate balance between open
 spaces and developmental pressures."

     As long as golf course construction and management continue to set a high  standard for
 environmental awareness, the golf industry will remain a preferred development option.


                                  Anne R. Leslie
                        U.S. Environmental Protection Agency
                                 401 M Street SW
                               Washington, DC 20460
                                  William Knoop
                               Texas A&M University
                           Research and Extension Center
                                 17360 Colt Road
                                 Dallas, TX 75252
    This chapter shows how communities can benefit when homeowners choose an IPM approach
to turfgrass management and city management is supportive through recycling programs. Although
healthy grass is generally viewed as an aesthetic asset  rather than a cash  crop, evidence is
accumulating for its positive health and environmental contributions. Balanced against all of this is
the potential risk from the pesticides that may be applied. So an IPM program that emphasizes
proper pesticide application without sacrificing turf quality is especially important. Reductions in air
and water pollution can be realized through maintenance of this quality groundcover. Some recycling
of urban solid waste is even possible, and as shown below, this can be an economic benefit to the

    Healthy turf can act as a buffer to delay or prevent movement of chemicals and soil from
agricultural sites to watersheds. Grass is used in orchards to absorb pesticides and minimize
erosion. Grassland experiences 84 to 668 times less erosion than areas planted to wheat or corn.
Studies show that an average golf course of 150 acres absorbs 12 million gallons of water during
a three-inch rainfall, and thick, carefully managed turfgrass has 15 times less runoff than does a
lower quality lawn  (Watschke, personal communication). By comparison, parking lots, streets, and
other paved residential areas load nearby waters with hazardous pollutants carried in runoff from
road surfaces, gutters and catch basins.

    Healthy turf can flourish with IPM techniques that also recycle sewage sludge, and detoxify air
and water pollutants. Using recycled sewage sludge compost to fertilize golf courses helps mitigate
groundwater pollution effects of waste disposal sites. Homeowners can purchase such materials
to use on their lawns so long as they grow no food nearby. Some of these materials are  discussed
in the chapter by Vargas.

    A healthy lawn can detoxify air pollutants. The capacity of grass is comparable to the same
leaf surface area contained in trees. In addition, turf is an excellent groundcover to diminish loss of
soil as dust, a significant air pollutant. Finally, a lawn can provide cooling to the home and lower the
energy consumption for air conditioning in the summer.

    Communities having limited landfill space have built incinerators to dispose of solid waste. In
this technology the burning of organic matter such as lawn clippings, which have a high  water and

nitrogen content, results in increased emission of the oxides of nitrogen. Reducing the quantity of
garden plant material to this solid waste disposal stream will help reduce air pollution.

    The Lawn Waste-Saver Program carried out in Piano, Texas addresses the problem of limited
landfill space. William E. Knoop of Texas A&M University Research and Extension Center at Dallas,
reports in Grounds Maintenance Magazine the only quantitative study of its kind that we are aware
of. The plan has since been implemented in other communities, including Fort Worth, Texas. It was
presented to the EPA Municipal Solid Waste Task Force in May  1988. This  presentation included
recent  data from Wichita Falls, TX, and a report, "Turfgrass Management Practices and Their
Influence on Pests," given by Philip F. Coibaugh of Texas A&M at the ACS symposium in  New
Orleans, August 1987. The  latter report shows how  this system is part of  an IPM program that
results in improved turf as well.

    The original article by Knoop is reproduced here to show how the program was implemented
by the City of Piano.  (Reprinted with permission from the  November 1982 issue of Grounds
Maintenance 1982, Intertec Publishing Corp., Overland Park, KS  66212.)


    Landfill space is at a premium for most cities. It is expensive to obtain. It is also expensive to
maintain. Cities surrounded by other cities often have used up all possible landfill space and must
find land in other areas. Few residents are eager to allow any city to develop a landfill next to them.
These  considerations make it highly desirable to make the most out of the currently used landfill.

    Piano, Texas, north of Dallas, is a bedroom community of about 80,000 people. To make the
city government run as efficiently as possible, the management created a Productivity Department
in the spring of 1980. It reviewed Piano's solid waste disposal system. During one week in mid-June
1980, productivity staff members rode each garbage truck on every route and recorded the number
of garbage bags containing grass clippings and the number of bags containing other garbage.

    The city officials found that 29.1 percent of all garbage bags picked up during the 1980 Piano
sampling period were filled with grass clippings. A bag of grass clippings weighs approximately 40
pounds, so Piano homeowners were placing nearly 700 tons of grass in the landfill. Because bags
of grass clippings weigh more than an average bag of other garbage, it was estimated that about
40 percent of the garbage truck's load (by weight) was grass clippings.

    If  analyzed on the basis of their dry weight, the 33,000 bags of grass clippings collected each
week contain approxi-mately 2 1/2 tons of nitrogen, 1/2 ton of phosphorus, 1  ton of potassium and
all the  remaining essential  plant nutrients.  When placed in a landfill,  their value has essentially
ended; their only function is to possibly become a future source of ground-water pollution.

                           EDUCATIONAL PROGRAM

    A cooperative public educational program between the city of Piano and the Texas Agricultural
Extension  Service was begun in April 1981  in an effort to  reduce  the amount of grass clippings
reaching the landfill. This educational program used the local newspaper,  area TV and radio, and
a flyer that the  city mailed to each of its nearly 19,000 homeowners. The goal of the program was
to encourage proper fertilization,  watering  and-most importantly-proper mowing. Homeowners
were advised that the management of golf courses (with the exception of greens), athletic fields
and other high-quality turf areas does not include the process of picking up grass clippings.


    The results of the  program, summarized in the accompanying table, were  encouraging.
Although the number of bags of other garbage increased by 12 percent, the number of bags of grass
clippings decreased by 11 percent, for a projected overall decrease of 23 percent. The percentage
of bags containing grass clippings was reduced from 29.1 percent in 1980 to 24.7 percent in 1982.
The total saving to the city was over $100,000. Perhaps more importantly, the burden on the landfill
was reduced.

     How unique is this problem? Piano is an upper middle-class city whose homeowners place
very high aesthetic value on their homes. As word of the success of the program spread, mainly
through city-government-oriented publications, more than 100 cities from  27 other states wrote
asking for details of the Piano program. A director of public works from an Ohio city indicated that
approximately 50 percent of the solid waste collection in summer was grass. He thought that 95
percent of homeowners bagged their grass clippings, indicating that the bagging of grass  clippings
may be a more universal problem than first considered. It might be hard to find a city without a
landfill problem and grass clippings may be a part of that problem.

     How did all this bagging of grass clippings get started? Perhaps we  homeowners  became
more and more lazy about mowing practices. Instead of removing no more than one-third of the
leaf surface area each  mowing and letting the growth rate dictate the mowing frequency, we tended
to let the calendar dictate mowing frequency. As a result, the heavy layer of clippings on  the lawn
presented a  real management problem.  Raking clippings certainly is  not a pleasant task and
mowers that collected the clippings in a container that could be emptied into a garbage can or plastic
bag became highly desirable.

     We homeowners  may have compounded the problem by also placing  such a great value  on
dark green  lawns. Such lawns require fairly high applications of nitrogen, which tend to  increase
growth rates. Promoters have never emphasized turfgrass varieties that produce reasonable growth
rates at low nitrogen rates.

                           HOMEOWNERS RECEPTIVE

     Perhaps it is  now time to provide  homeowners with  good, basic turfgrass management
information that encourages such practices as proper mowing. The experience in Piano indicated
that most people did not know they did not have to bag grass clippings. They assumed that, because
the mower  had a bagging attachment, there  was no alternative.  The program demonstrated to
homeowners that if mowing frequency was increased to once every 5 days, then the need to bag
was ended. Most homeowners felt this increase in mowing frequency was far more desirable than
bagging clippings. The program also demonstrated the value of a 3-1-2 fertilizer ratio and the value
of a slow-release nitrogen source in slowing growth rates without any sacrifice in lawn quality.

     Mulching mowers can  be expected to  play  an  important part  in  a non-bagging  lawn
maintenance program.  More research with mowers in controlled-management situations is  needed.

     Our energy as a turf industry has been concentrated in areas that benefit relatively few people.
Now we must consider a larger issue, such as the bagging of grass clippings  and its effect  on

                                        TABLE 1
                            SUMMARY OF THE PLANO, TEXAS
                          WASTE-SAVER LAWN CARE PROGRAM
Number of homes
Number of stops for garbage
Number of stops that had bags
of grass
Number of bags of grass
Number of  bags of other
Total bags of garbage
Truckloads of garbage







   + 9%


   + 5%

                                    Roger C. Funk
                           The Davey Tree Expert Company
                                 1500 N. Mantua Street
                                   Kent, Ohio 44240
    The  lawn care industry has experienced unprecedented growth in the last decade and the
demand for our services is still growing.

    The recent pesticide controversy has raised questions concerning the safety of pesticides and
our current practices. It has also increased consumer awareness of our industry, expanding the
market for quality-conscious lawn care operators. There has never been greater opportunity for
those willing to accept the challenge.

    Lawn care operators are developing  an image problem. We are being perceived not as an
industry that maintains the health of turfgrass but rather as an industry that applies pesticides. Of
course we do apply pesticides but only as one of the many services that we provide.

    Although several factors could contribute to the public's perception of our industry, the most
important are media coverage, high market visibility and the overuse of pesticides. This perception
can be changed only if we recognize that education is an integral part of the services we provide
and that we must limit our use of pesticides through monitoring and selective applications and the
use of alternative materials whenever possible.

    One of the best methods of educating the public is through an educated media. Too often we
take a combative or defensive attitude toward the media since they usually fail to present balancing
viewpoint about lawn pesticides. It is their objective to report what they consider to be newsworthy.
Unfortunately for  us, the application of pesticides to millions of lawns without a single incident is
not considered newsworthy. However, the perceived or alleged injury to just one person from those
millions of applications is news and would be reported.

    The  high visibility of the lawn  care industry has also contributed  to our image as  pesticide
applicators. Because of the demand for our services, the lawn  care  industry has  been highly
successful. And  because  of our  success, we're  highly visible  in the urban  and suburban
environment. There are estimates as high as 40-60% if the homeowners in any given market having
a commercial applicator do their chemical lawn maintenance.

    As success and visibility increase, questions and concerns about the effect of our applications
on health  and the environment also  increase. Do-it-yourselfers use the same fertilizers and
pesticides we use, but they maintain a lower visibility in the neighborhood.

    The noticeable odor of pesticide applications is largely the result of the overuse of pesticides.
Most lawn care operators apply pesticides to the entire lawn if pesticides are needed on any portion
of the  lawn. Some may apply the same granular or liquid formulation to all of the lawns serviced
within a geographic area based on the predicted pests for that time of year. This practice leads to
the unnecessary application of pesticides and contributes to the concern of pesticide exposure. In
addition, "shot gun" applications are not an economically or agronomically sound practice since no

benefit is derived from a pesticide application if a pest is neither present nor anticipated within the
residual period of the pesticide.
     In order to  change the public's perception of our industry, we must change the way we do
business. Change is seldom easy, particularly for an established company with a growing market
share. Change, however, is an integral part of any successful company. One definition of success
is to find out what the public wants and then give it to them. When the lawn care industry first started,
our customers  wanted green, weed-free  lawns. They still want  the same thing  but with less
pesticides applied to achieve it.
     Last year, insecticides and herbicides in Davey lawn care services in selected territories were
effectively reduced 40% to 50%, respectively, through the use of the patented Davey Customizer.

     The Customizer is specially  designed for spot application of pesticides. Pesticides are not
tank-mixed, but are secured in a separate reinforced tank and are injected in the fertilizer line only
as needed. Another feature of the  Customizer is its specially designed no-drift nozzle.

     In a five-area representative sample of Davey lawn care operations (Akron, OH; Charlotte,
NC; Minneapolis, MN; Rochester,  NY; and Washington, DC), 1987 results show that 4,800 gallons
of herbicide were used in 1985 compared to 2,260 gallons in 1987 with the use of the Customizer.
(Fig 1). In addition, insecticide use was  reduced from 1,020 gallons to 600 gallons. (Fig 2). This
represents a 52.9% reduction in herbicides and a 41.1% reduction in insecticides.

     Based on  our field experience in the five test markets, we are projecting a company-wide
reduction in lawn pesticide use in  1988 of almost 10,000 gallons-without any increase in insect or
weed problems.

     Petrochemical pesticide use can be  reduced in other ways. Alternative materials such as soap
and citric oil are being researched. Both materials are effective insecticides and currently are used
in other industries. Biological controls may prove practical.

     Milky  spore disease has reportedly been reformulated and  is more effective  on Japanese
beetles. Tests are under way for nematode control of grubs and fungal control of chinch bugs.

     Electrostatic sprays may reduce drift of conventional pesticides by electrical attraction  of spray
particles to plant surfaces. This allows the rate of application to be reduced.

     Micro-encapsulation of pesticides  can  potentially reduce the toxicity of pesticides while
reducing odor.

     Our industry should investigate alternative methods of pest management and discuss possible
solutions with university personnel  and material equipment manufacturers. We should  not be
committed  to any material  or method of application - only to provide the quality of service the
customer wants and has a right to expect.

     In summary, the lawn care industry is partially responsible for the pesticide controversy due
to our high visibility in residential areas and the overuse of pesticides. The news media has
contributed by  reporting only "newsworthy" items that sensationalize  and distort the risks from
pesticide exposure. We can, however, improve the quality of our service through education, and
through alternative  materials  and methods of application. Controversy almost always results in
change... and with change comes  opportunity.

     Editor's note:   A more technical treatment of how the Davey Co. has responded to the need
                   for change is presented in the following section dealing with ornamentals.

                         DAVEY'S PLANT HEALTH CARE
     Pest management is an important service offered by Arborists to protect trees and shrubs in
the landscape. Concerns for public health and the environment, however, have resulted in increased
insurance costs and restrictions in the use of pesticides. Many tree care companies are weighing
the benefits of  a pest  management service against the risks  involved in the continued use of

     In January 1985, the Davey Company scheduled our first Plant Health Care (PHC) Seminar
to discuss a comprehensive approach to  improving tree health through proper selection, planting,
and care. Since the concept of PHC emphasizes preventative maintenance, the health of the tree
(not pest control) became the central focus of our service.

     Neilsen (Reference #2) defines a similar concept and provides a framework for implementation
in the November, 1986  issue of the Journal of Arboriculture.

     One of the objectives of our PHC concept was to reduce the use of traditional pesticides.
Horticultural oil was  an obvious and  underused alternative and  we began testing its use for
foliage-feeding insects. In addition, we began testing reduced rates of the registered insecticides
in combination with soaps, horticultural oil, vegetable oils, and citric oils. More recently, we have
begun testing Neem oil, diatomaceous earth, and detergents.

     Our earliest successes were with soap plus reduced rates of insecticides. After two years of
laboratory and field testing, we introduced the approved combinations in five test markets in 1987
and implemented the "program"through our U.S. market in 1988. We anticipate a 75% reduction in
pesticide use this year with further reductions by 1990. Additional reductions are projected through
the increased use of alternatives, selective spraying and improved methods of application.

                                EFFICACY TESTING

     Preliminary research with Safer Insecticidal  Soap indicated that soap alone would satisfactorily
control most soft-bodied insects and mites, but provided no residual effect. Testing was begun on
reduced rates of the petrochemical pesticides in combination with  soap to determine efficacy for
sucking as well as chewing insects and mites.

     in most cases soap was found  to enhance the  control achieved with reduced rates  of
pesticides. This was particularly true with sucking insects and mites, but also with Japanese beetle.
Tempo, a synthetic pyrethroid, was sprayed on linden leaves in the field. Leaves were also treated
with Safer soap and Tempo plus soap. Foliage  was collected one week later. During this period,
rainfall was approximately 1-1/2 inches. Japanese beetles were introduced onto the foliage in the
laboratory. After a feeding period of two days, mortality rates were recorded. The results are in the
following chart:

                                       Table 1.
                              Japanese Beetle on Linden

         Insecticide             Rate/100 gal.            % Control

         Tempo                  0.5 oz.                  17
         Soap                   128oz.                 0
         Tempo + Soap           0.5 oz. + 128 oz.         92

     Tempo alone at 1/4 the recommended rate and soap alone at 1/2 the recommended rate did
not control the beetles. The same rates of Tempo and soap when combined, however, provided
92% control.

     In another experiment, Tempo and soap were  tested for contact control of aphids. Rose of
Sharon twigs infested with aphids were brought into the lab, placed in individual vials of water and
sprayed. Results of this experiment are given in the chart below:

                                       Table 2.
                               Aphids on Rose of Sharon

         Insecticide             Rate/100 gal.            % Control
         Tempo                  0.5 oz.                  40
         Soap                   64 oz.                  90
         Tempo + Soap           0.5 oz. + 64 oz.          98

     The combinations of  Tempo plus soap again outperformed either component individually
applied. The tests demonstrated that the rate of Tempo can be reduced significantly when combined
with soap for the control  of aphids and Japanese beetles. Tests with other insecticides, such as
Dursban, Orthene, and Sevin, have shown similar results in combination with soap or horticultural
oil, although the effective  rates vary. In  one test, Dursban  at 1/16 the  recommended rate in
combination with horticultural oil (1 gal/100) provided mite control equal to Dursban at full rate.

                            COMPATIBILITY TESTING

     The current soaps which are registered for ornamentals are strongly alkaline and may react
differently with different insecticides or in different water sources. For example, in some of our
markets, soap causes Sevin to deactivate within several hours of mixing and turn  a brown to
reddish-brown color -- which stains! In these situations, additives are necessary to combine soap
with the insecticide. Davey researchers are working with soap manufacturers to alter the formulation
of soaps so that additives may not be necessary in the future.

                            PHYTOTOXICITY TESTING

    There are a number of plants listed as being injured by Safer's soap. (Reference #3) In addition,
we have found that drought-stressed trees are more susceptible to injury from soap than standard
pesticides and that, under certain  conditions, the new growth of evergreens may be injured. In
most cases, we did not find that the addition of a reduced rate of pesticide altered the occurrences
or severity of the  pnytotoxicity. Although precautionary statements regarding phytotoxicity from
horticultural  oil persist, Johnson (Reference #1) has not observed injury when light, superior oil is
applied to deciduous foliage, provided that the proper rate is applied and that the tree is not under
moisture stress. Injury which we observed occurred only when oil was  combined with Sevin and
may have been related to drought stress and/or excessive heat and  pressure.

                               SELECTIVE SPRAYING

    Selective spraying involves monitoring to determine the  presence and population levels of
insects, and spraying only those trees and shrubs that have a pest problem. Pheromone traps  are
a useful tool in determining the most  effective timing for control of  clearwing  moth borers. Traps
have also been used successfully in identifying species of pine tip moth. This is particularly useful
when first starting a monitoring program or when opening a new market.

     Personnel training and resource information is essential to the success of our PHC programs
since the person making the application normally determines which trees and shrubs will be sprayed.
The Technical & Research staff developed pest/host timing charts for each of our field offices which
are continuously being refined with the assistance of an  on-site PHC trainer. (Figures 1 & 2) The
charts provide guideline for anticipated insect and disease problems. In addition, the trainers attend
week-long classes at our headquarters in Kent, Ohio, each year to enable them to train and monitor
the effectiveness  of the technician  in the field. Extension courses developed in-house are part of
the training supervised by the PHC trainer. The Technical staff also  visits each territory each year
to further train and motivate the field staff.

     Educating clients  is necessary, not only as a potential participant in the monitoring process,
but also to accept the concept of selective spraying. Clients who have been on a  program where
all the trees and shrubs have been sprayed are often reluctant to accept selective sprays. Literature
which explains Davey's approach to Plant Health Care is provided to clients as well as Fact Sheets
which  discuss any major problems on the property. Information is also available to help clients
select  the proper  plants for site conditions and the proper transplant procedures and  cultural
requirements for those plants.
    Application techniques can reduce the potential for drift and reduce the volume of pesticide
    Davey  researchers tested  various pressures and disc sizes to determine the effect on drift.
Trees should be sprayed with a large disc or nozzle and only sufficient pressure at the gun to reach
the top of the tree. A ball valve or similar control at the spray gun will allow the  technician to adjust
the flow rate and pressure at the nozzle without returning to the truck.

    Excess spray volume applied to trees and shrubs is a common  problem, particularly with new
technicians. Guidelines were developed by Davey researchers indicating  the spray  volume  needed
for coverage of different size canopies. For example, a tree 50-ft. high and 60-ft. wide would require
25 gallons of spray mix. This gives  the technician and his manager a tool for comparing the actual
with the estimated  material usage.


     A survey of all field managers was conducted in 1987 to estimate material savings from the
 improved application techniques. Although the actual material savings varied, depending upon the
 pest problem and the experience of the technician, the least savings reported was 5%.

     In summary, Davey's Plant Health Care program enabled us to reduce our use of traditional
 pesticides by 75-80% in five test markets in 1987. Fifty percent of the savings was achieved through
 the use of alternative materials,  25% by selective spraying, and  5% by improved  application
 techniques. Based on our findings we are projecting a reduction in use of over 20,000 gallons of
 pesticides in 1988 for our tree care markets-with no reduction in the quality of service  to our

                                    Literature Cited
Johnson, W. J., 1980. Spray Oils as Insecticides. Journal of Arboriculture. 6(7); 169-174.
Neilsen, D. G., 1986. Planning and Implementing a Tree Health Care Practice. Journal of Arboriculture. 12(11): 265-268.
Safer, Inc. Phytotoxictty Information. May 8,1984.

                     FIGURE 1
                LAWN CARE

        '85 '87
'85 '87
'85 '87
'85 '87
'85 '87
'85 '87

                    FIGURE 2
              LAWN CARE
            '85 '87
'85 '87
  '85 '87


•Minneapolis, MN does not have a high insect control problem
                               '85 '87
                   '85 '87


    Current Research Towards
Understanding the Pest and the Site



                      S. A. Miller, G. D. Grothaus, F. P. Peterson,
                   J. H. Rlttenburg, K. A. Plumley, and R. K. Lankow
                             Agri-Diagnostics Associates
                                  2611 Branch Pike
                               Clnnaminson, NJ 08077
    An integrated pest management (IPM) strategy for crop protection and production seeks to
achieve maximum yields while minimizing crop damage, cost to the grower, and environmental
hazards (1). For any crop, an effective IPM program must include the accurate and timely detection
of pests and pathogens. For most plant diseases, few tools have been available to the grower or
crop consultant  for this crucial aspect of disease management, resulting in  a reliance on
symptomatology for disease diagnosis (11). However, symptom expression can be highly variable,
depending on the crop variety, maturity, environmental conditions, and other factors. In addition, a
number of pathogens may cause similar  symptoms  on the same plant variety. Reliance on
symptoms usually precludes the early detection of pathogens, which may hinder the implementation
of preventive management practices.

    Recent advances in biotechnology are being applied to plant pathogen  systems to provide
diagnostic tests directly applicable to  pathogen detection  at the grower level (8,9). For broad
acceptance  among crop managers,  these  assays must be  sensitive, specific, reliable  and
user-friendly. These  criteria  can be  met by  immunoassay-based  diagnostic systems.  Agri-
Diagnostics Associates have developed immunoassays for the detection of three fungal pathogen
complexes in turfgrass: Pythium Blight, Rhizoctonia Brown/Yellow Patch, and Dollar Spot.  The
basic concepts of immunoassay technology are described, focusing on the Pythium Blight assay
and its effectiveness in detecting the disease in golf course turfgrass.
    Immunoassays are tests in which antibodies are used as analytical chemistry reagents (7).
To a large extent, the antibody is responsible for the specificity and sensitivity of the immunoassay,
and two major types (polyclonal and monoclonal) are employed. Polyclonal antibodies are produced
and secreted in  experimental animals by a large number of B-cell clones which proliferate  in
response to  recognition of chemical structures or determinants presented by the injected antigen.
Polyclonal antisera can be produced in commercial quantities by immunizing large numbers  of
small animals or a few large animals such as sheep and goats in a relatively short time frame (3-6
months), and usually provide a robust antibody population  due  to the variety of immunoglobulin
types in the sera. The generalized specificity of a polyclonal antiserum to a number of determinants
on an antigen can be advantageous. If the target analyte is heterogeneous and somewhat variable
in structure or the relative ratios of its various  components, a polyclonal antiserum may provide a
certain amount of "recognition buffering".
    Monoclonal antibodies are now finding considerable application in immunoassay by providing
a very high level of specificity as well as a potentially unlimited source of uniform antibody (4,5,6).
Monoclonal antibodies are produced by fusing  antibody-producing cells isolated from the spleen of

an immunized animal with "immortaJ"myeloma cells from tissue culture. The cells are transferred
to a selective medium that will only support the growth of hybrid cells, called hybridomas. Individual
hybridomas are subcloned and allowed to divide and produce antibody. Antibody secreted into the
cell culture  medium is  then tested for desirable antigen-binding characteristics. Since each
hybridoma cell line produces only one type of monoclonal antibody, it is possible to select antibodies
with the specificity and sensitivity required for specific  applications. Hybridomas may be stored
frozen in  liquid nitrogen and recovered  at any time to continue reproducible  production of the

     For practical application of the unique properties of  antibodies in a diagnostic assay, the user
must  be able to determine whether the  antigen/antibody reaction  has taken place. A variety of
visualization and detection methods  have been designed for this purpose. Enzyme immunoassay
(EIA) is probably the immunoassay technology most widely applied today (7,9). One widely used
EIA is the double antibody or  "sandwich" immunoassay (2,3), in which an untagged or capture
antibody is bound to a solid phase, such as beads, membranes or the wells of a microtiter plate.
The test sample and enzyme labeled antibody are added sequentially, and unbound components
are removed by washing after each incubation. Enzyme labeled antibody is detected by the addition
of a color-producing substrate. The  capture antibody is particularly useful when the test sample
consists of a complex mixture of materials, such as a plant extract. The capture antibody binds the
target antigen, while other components of the  sample, which could interfere with subsequent steps
in the immunoassay, are washed away.

     One  of the simplest immunoassay formats uses a dipstick as the solid phase (7). The dipstick
is moved from one reagent to the next and the assay result is determined by examining the dipstick.
Visualization of the bound enzyme-labeled antibody occurs when the enzyme converts the substrate
to an insoluble colored product that binds to the dipstick.  Quantitative results can  be obtained
through the use of an inexpensive field-adaptible  reflectometer that measures the color intensity
on the dipstick.
                              KIT CHARACTERISTICS
     The Agri-Diagnostics turfgrass disease detection kits employ the dipstick format for performing
a double antibody sandwich immunoassay. The assay requires no specialized equipment and can
be completed in less than 4 hours.

     The turfgrass sample is ground on an abrasive pad which is placed into the sample extraction
buffer. The grinding homogenizes the sample, breaks up the fungi, and presents  a controlled
amount of sample (material trapped within the abrasive surface) into a fixed volume of extraction
buffer. In the next step a fixed volume of enzyme-tagged antibody, specific for the pathogen, is
added into the extraction solution.  Then  the dipstick,  with  antibody specific to the pathogen
immobilized to its surface, is placed into the reaction mixture. During this step, the  antibody on the
dipstick captures any pathogen in the sample, and the enzyme-labelled antibody simultaneously
tags the pathogen. After washing away any material not specifically bound, the dipstick is placed
in a substrate solution which forms a colored precipitate in the presence of enzyme. The assay is
quantitative, yielding a color endpoint, the density of which is directly  related to the amount of
pathogen in the turfgrass sample.

    The graph in Figure 1 shows the dose response curve for the Pythium detection assay. The
sensitivity limit based on fungal protein material is approximately 20 ng protein/ml. A reflectometer
was used to quantitate the intensity of the reaction zone on the dipsticks.

    The specificity of the immunoreagents used in the  dipstick assay was determined using a
"multiwell-'EIA format. Dilutions of soluble extracts of isolates of fungi known to occur as pathogens
or saprophytes on turfgrass were tested in a direct double-antibody EIA using standard protocols
(3). The second ("tag")  antibody was conjugated  with horseradish peroxidase,  and ABTS
(2,2'-Azinobis(3-ethylbenzthiazolinesulfonic Acid) was the  substrate used.

    The reactivity of nine Pythium spp. associated with turfgrass  as pathogens or saprophytes
with the assay immunoreagents is shown in Table 1. All  of the Pythium species associated with
Pythium-induced disease, including P. aphanidermatum. P. ultimum. P. graminicola. P. aristosporum.
£. arrhenomanes.  and P. myriotylum are detected by the  assay. Species described as  weak
pathogens or saprophytes of turfgrass, including R, torulosum. FL vanterpooliir and H rostratum are
not detected. Other genera of turfgrass pathogens or saprophytic fungi associated with turfgrass
also  are not  detected. Among the genera  tested  were  Rhizoctonia,  Sclerotinia. Fusarium.
Drechslera. Bipolaris. Laetisaeria. Limonomyces. Curvularia.  Rhizopus. Typhula. Trichoderma and
                                   FIELD RESULTS
     The Pythium detection assay was evaluated on a southern New Jersey golf course in 1986
and  1987. The 1986 test was of limited duration, carried out during an outbreak of Pythium blight
on several of the course's fairways and greens in July of that year. Environmental conditions were
conducive to Pythium blight for the duration of the testing period. The data resulting from tests on
the green and fairway with  the most severe disease are presented. The green that was studied
(Green 4) contained bentgrass and a small percentage of annual bluegrass. Pythium blight occurred
primarily on  the collar, and  samples were taken from this part of the green. The fairway studied
(Fairway 7) consisted of perennial ryegrass, and was severely damaged by the disease. In order
to determine the relative concentration of the pathogen at various stages of disease progression,
samples were taken from the middle and edge of patches or streaks caused by Pythium spp., as
well as from symptomless areas in proximity with the symptomatic areas. Samples of turfgrass from
areas tested with the Pythium kit were also plated out on  a selective medium for Pythium spp.
isolation (10).

     Pythium spp. were detected in both asymptomatic and symptomatic perennial ryegrass and
bentgrass samples from the same green  or fairway (Table 2). Pythium assay results were usually
higher for symptomatic samples than for asymptomatic samples, as were Pythium spp. isolation
frequencies.  For all five of the asymptomatic samples shown in Table 2, Pythium spp. were detected
by the immunoassay, although they were isolated  from only three of the five samples.  Since the
samples were tested when environmental conditions were optimal for Pythium blight and prior to
the application  of Pythium control fungicides, Pythium spp. may have  been present in the
asymptomatic turfgrass samples at a high  enough  level to be detected but were not causing
symptoms. Meter readings for Pythium assays of samples taken during conditions not conducive
to Pythium blight development, or when the disease  is  well under control as a result of fungicide
application, are usually in the 0-10 range (see Figure 4,5, below).

     In general, the highest meter readings for blighted turf were obtained by sampling at the edge
of patches or streaks (Figure 2). While Pythium spp. could usually be detected in dead grass in the
center of a patch, high levels were detected more consistently at the leading edges.

     Pythium spp. were detected on Fairway 7 and Green 4 throughout the testing  period. A
fungicide effective against Pythium spp. was applied on July 10, which was followed by a decrease
in meter readings for samples taken from both the green and the fairway. Meter readings continued
to decrease for samples taken from the green, while the readings for fairway samples increased to
pre-fungicide application levels. These results reflect the amount of disease development on the
green and fairway; Pythium blight damage was somewhat localized on the green, which had begun
to recover by the end of the testing period. The damage on the fairway was extensive in the area
that was tested, and the ryegrass turf did not recover quickly.

     In 1987, a monitoring program was initiated on Green 4 and Fairway 7, beginning in late May
and extending through the summer until termination  at the end of  August. Six subsamples were
collected from the green and its collar, bulked separately, and thoroughly mixed. On the 7th Fairway,
an  area surrounded by trees and  approximately  150 yards from the green was  sampled. Six
subsamples were taken from an area no larger than a green and bulked. Two dipstick assays were
run for each bulked sample. Leaf blades were plated onto Pythium-selective medium as described
above. Designated areas were sampled before mowing in the morning to maximize the amount of
foliage that could be sampled, as well as to permit  visual detection  of pathogen signs (mycelium),
if present.

     As a result of the damage caused by Pythium blight to the greens and fairways during 1986,
the golf course superintendent instituted a rigorous fungicide spray  program in 1987. Beginning in
late May, greens and fairways were sprayed on a weekly basis with three fungicides effective against
Pythium spp. in rotation. As a result, no symptoms of Pythium blight were observed throughout the
testing  period, even during periods when  the  environment was  highly  conducive  to disease
development. Results of the monitoring program  using the Pythium detection assay are presented
in Figure 4. Conditions favorable for Pythium blight  first occurred on May 29; low positive readings
were observed for the  sample from the collar of Green 4, which was taken from the area most
severely affected in 1986. Results were negative for the samples from the Green 4 and from Fairway
7. The first fungicide application was made on May 29 after the sample was taken; all subsequent
Pythium detection assay  results were negative for Green 4 (including  its  collar) and Fairway 7.
Thirty isolates of Pythium spp. were recovered during  the testing period, five of which proved to be
pathogenic in standard pathogenicity tests.

     The negative results obtained  with the Pythium detection assay were clearly correlated with
the lack of symptoms of Pythium blight on the greens and fairway tested. With the exception of the
low positive reading observed for the collar of Green 4 on  May 29,  Pythium  spp.  did not reach
detectable levels at  any time during the testing period. These results, especially when compared
to the results of the  1986 trial, attest to the efficacy of currently available fungicides in controlling
Pythium blight. However, the use of fungicides in this instance appears to have been excessive;
our data (not shown) indicate that fungicide applications may not be required until meter readings
reach 10-15, depending on the disease history of the turfgrass in question. By monitoring greens
and  fairways on a regular basis using the Pythium detection  assay, increasing populations of
Pythium spp. can be detected, and superintendents may more precisely time the  application of

    The sensitivity and specificity of the dipstick assay system will make it possible for golf course
superintendents and  other turf managers to a) correctly diagnose turfgrass disease, b) detect
pathogens at an early stage of disease, before symptoms appear, and c) monitor the development
of pathogens in established turfgrass stands during periods of disease risk. An effective disease
monitoring program will include a determination of the baseline readings for particular stands (i.e.
greens, fairways, tees) during periods of low risk, followed by regular monitoring during the season.
This capability will enhance the effectiveness of currently  used disease  control measures and
promote an integrated approach to disease management in turfgrass.

  1.   Andrews, J.  1983.  Future strategies for  integrated control, in: Challenging  Problems ]n  Plant Health, ed. I
        Kommedahl, P. H. Williams. American Phytopathological Society, St. Paul, MN. pp.431-440.

  2.   Clarke, M. F. 1981. Immunosorbent assays in plant pathology. Ann. Rev. Phytopathology 19:83-106.

  3.   Clarke, M. F., Adams, A. N. 1977. Characteristics of  the microplate method of enzyme-linked immunosorbent
        assay(ELISA) for the detection of plant viruses. J. Gen. Virol. 34:475-483.

  4.   Galfre, G., Milstein, C. 1981. Preparation of monoclonal antibodies: strategies and procedures. Meth. Enzymol. 73:

  5.   Coding, J. W. 1983. Monoclonal Antibodies: Principles and Practice. Academic Press Ltd., London. 276 pp.

  6.   Halk, E. L., DeBoer, S. H. 1985. Monoclonal antibodies in plant disease research. Ann. Rev. Phytopathology 23:

  7.   Lankow, R. K., Grothaus, G. D., Miller, S. A. 1987. Immunoassays for crop management systems and agricultural
        chemistry, in: Biotechnology in Agricultural Chemistry, ed.  H. M. LeBaron, R. O.Mumma, R. C. Honeycutt, J. H.
        Duesing. ACS Symposium Series 334:228-252, American Chemical Society, Washington, D.C.

  8.   Miller S. A. 1988. Biotechnology-based disease diagnostics. Plant Disease 72:188.

  9.   Miller, S. A., Martin, R. R. 1988. Molecular diagnosis of plant disease. Ann. Rev. Phytopathology 26:409-432.

 10.   Schmitthenner, A. F. 1962. Isolation of Pythium from soil particles. Phytopathology 52:1133-38.

 11.   Strandberg, J. 0.1986. Disease and pathogen detection for disease management, in: Plant Disease Epidemiology.
        ed. K. J.Leonard, W. E. Fry. MacMillan Publishing Co., New York. pp. 153-179.

                                   TABLE 1
    Reactivity of isolates of Pythium  species associated with turfgrass In a double antibody
immunoassav using  anti-Pythium aphanidermatum antibodies. Extracts of each isolate were
standardized at a protein concentration of 1.0 ug/ml. Absorbance values (405 nm) are represented
as the mean of all isolates tested.
   Pythium  species     Number  of Isolates       Mean  Absorbance
                               Tested             (405  nm) *
   E- aphanidermatum           10                  >2.00
   E- graminicola                1                   >2.00
   P. ultimum                   2                   >2.00
   P. myriotylum                2                   >2.00
   P. aristosporum               1                   >2.00
   P. arrhenomanes             4                   >2.00

   P. torulosum                  2                   0.12
   E. vanterpoolii                1                   0.00
   P. rostratum                  1                   0.09
   1 Absorbance  readings >  2.0  are off-scale.

                                   TABLE 2
    Detection of Pythium spp. in perennial ryegrass and bentgrass golf course turf by the Pythium
detection assay and isolation from leaves using a selective medium. All samples were taken prior
to application  of fungicides for control of pythium blight.
    Turfgrass    Symptoms*
 Pythium  Kit    Pythium  Isolation
Meter  Reading      Frequency2
Pythium blight
Pythium blight
Pythium blight
Pythium blight
Pythium blight
.. 3 / 8
    1  Asymptomatic turf grass  samples  were  taken from areas within  10  ft
    of symptomatic  turfgrass.
    2  Indicates the number  of leaves/total plated on  selective medium  from
    which Pythium spp. were observed to grow out.

                                     FIGURE 1
    Dose response curve for the Pythium detection assay. The sensitivity limit of the assay, based
on fungal protein of Pythium aphanidermatum. is approximately 20 ng protein/ml.
   .1            1
[Fungal protein] tig/ml

                                     FIGURE 2
     Prevalence of Pythium spp. in blighted patches and  surrounding asymptomatic  perennial
ryegrass during a severe outbreak of Pythium blight, determined using the Pythium detection assay.
In most cases, levels of Pythium spp. were highest at the edge of patches and lowest in the center
of patches. Asymptomatic ryegrass samples taken from areas in close proximity to symptomatic

areas also contained detectable levels of Pythium spp.


    50 -i
    40 -


>2" Away
    10 -i
                                    Date in 1986

                                      FIGURE 3
    Detection of Pythium spp. in perennial ryegrass (Fairway 7) and bentgrass (Green 4) using the
Pythium detection  assay.  Values represent  the  mean  of two to four samples. Environmental
condition remained highly favorable for Pythium blight development through the testing period. An
application of a Pythium control fungicide was made on 7/10; Green 4 began to recover in the latter
part of the  testing  period,  but symptoms persisted on Fairway 7. The dotted line  in the figure
represents the threshold of positive detection for the assay.

                                                        -13—  FAIRWAY 7

                                                        ••o—  GREEN4







                                      DATE in 1986

                                       FIGURE 4
     Results of a monitoring program for the detection of Pythium blight on Green 4 and Fairway 7
 in 1987. Conditions favorable  for Pythium  blight occurred  initially on May 29, and  continued
 intermittently until late July. Pythium spp. were detected by the assay on the collar of Green 4 on
 May 29; however,  regular application of Pythium control fungicides kept the pathogens at a
 non-detectable level. No symptoms of Pythium blight occurred during the testing period. The dotted
 line in the figure represents the threshold of positive detection for the assay.
40 -
       30 -
  1    20 H
       10 -

—o —  GREEN 4 (COLLAR)

—••—•  GREEN4
                                                                        3  fe
                                                                        0  3
                                                                        O  O
                                       DATE in 1987


                   J. M. Vargas, Jr.; D. Roberts; T. K. Danneberger;
                              M. Otto & R. Detweller
     Departments of Botany and Plant Pathology, and the Pesticide Research Center
                             Michigan State University
                              East Lansing, Ml 48824
    Biological management of turfgrass pests, including some fungal diseases, insects, and weeds
is now possible. These management tools  consist of cultural practices to encourage natural
predators as well as the direct application of beneficial organisms that are antagonistic to the fungal

    Necrotic  ring spot (MRS), caused by Leptosphaeria korrae. is a serious disease of Kentucky
bluegrass (Poa  pratensis) in the northern areas of the cool season grass  growing region. The
disease was formerly referred to as Fusarium blight and mistakenly believed to be caused by either
Fusarium roseum or Fusarium tricinctum. Koch's postulates were never completed for this disease
with either F. roseum or F. tricinctum. as all attempts to produce patch or "frog eye "symptoms in the
greenhouse or the field failed. Further investigation revealed a root pathogen associated with these
disease symptoms which was eventually identified as L korrae. Koch's postulates were completed
in both greenhouse and field Inoculation studies with L. korrae where actual patches and "frog eye"
symptoms were produced, providing the  final proof of the true cause of this  patch  disease on
Kentucky bluegrass in the northern areas of the cool season grass growing region.

    L. korrae is pathogenic to P. pratensis over a wide temperature range (15-28 degrees C.). L.
korrae attacks the root systems of Kentucky bluegrass plants primarily during the cool weather of
the spring and fall. The patches range in size from 7-8 cm up to 1 m in diameter.  When the disease
occurs in cool weather, red and straw colored blades are intermingled in the infected area of the
patch. When the disease symptoms occur during the warm weather, the infected turf originally
appears as wilted turf, later turning to straw color.

    Necrotic  ring spot is currently managed  by high rates (compared to rates normally used to
manage  foliar turfgrass  diseases like dollar spot or anthracnose) of the following fungicides:
benomyl, thiophanate, thiophanate-methyl, iprodione, and fenarimol.

    Studies of the environmental conditions necessary for necrotic ring spot symptom development
indicated low soil moisture was important. An irrigation  study was established to determine the
effects of irrigation  on necrotic ring spot. The treatment included a daily irrigation treatment
(1/107day), an 80% pan treatment (replacing 80% of the moisture lost from an evapro-pan twice a
week), and a no supplemental irrigation treatment. Each replication included three sub-treatments:
a muck sod, a mineral sod, and a seeded blend of three JEL. pratensis cultivars (Baron, Victa, Bristol).


     In 1986 and 1987 necrotic ring spot symptoms developed In the muck and mineral sod 80%
pan treatments and non-supplemental irrigation plots. No symptoms occurred in the daily irrigated
plots. This is believed to be due to the increase in the beneficial microbial populations. There was
an increase in the number of beneficial fungi, the number of actinomycetes (known producers of
anti-fungal  compounds) and beneficial bacteria. The effect of these various organisms on the
development of necrotic ring spot is being investigated. Similar results have been observed in the
reduction  of  melting-out, caused by Dreschlera poae and  leaf spot,  caused  by Biopolaris
sorokinianum in other irrigation studies. This disease reduction has been correlated to an increase
in microbial populations. Two other pests that have been reported to be managed by irrigation are
the chinch bug and bill bug. The possibility of managing five £L pratensis turfgrass pests biologically
through the cultural practice of irrigation now appears feasible.
     In May 1984 a curative study was established on a heavily diseased P, pratensis sodded area
 in Novi, Michigan.  The study was laid out with three replications of 1.83  x 2.44 m2 plots in a
 randomized block design. The condominium site at Novi was irrigated with an automatic irrigation
 system and in 1984 received, in addition to our treatments,  the same four fertility and herbicide
 treatments as the rest of the complex, including a total of 180 kg N/ha. In 1985 and 1986 this area
 did not receive any additional fertilizer treatment other than those we applied. Green Magic and
 Soil Aid were applied using a CO2 small plot sprayer at a volume of 454.2 I/ha., equipped with a
 .914 m boom.  Lawn Restore was applied by hand to individual plots. The results of Green Magic
 plus Soil Aid and Lawn Restore when compared to a nitrogen check can be seen in Table 1. They
 show complete recovery in the Green Magic plots when treatments were applied three times a year
 in May, July, and September at a 480 kg/ha rate. The amount of necrotic ring spot increased 303%
 during the same period of time.

                                       TABLE 1

 Mean percent reduction3 in necrotic ring spot patches from 5/23/84 to 8/14/86 at Novi, Michigan.

           Treatment  Month of Application         8/14/86        meansep.c
                                                 mean % redb

           Green               MJO                   100               a
           Lawn               MJS                   100               a
           Check                AS                    -303               b
a Calculated by subtracting number of patches per plot on 8/14/86 from the number on 5/23/84,
  dividing this by the number present on 5/23/84, and multiplying by 100.
b Percent disease reduction. Mean of three replications.
  Means followed by the same letter are not significantly  different by LSD (.05).
     Biological management of soil-borne disease through the use of microbes can act through two
mechanisms. The first is competition for nutrients in the thatch and soil between the beneficial
microorganisms and the pathogens. By utilizing available nutrients, they can deny the pathogens
the nutrients needed to stimulate germination of resting structures (spores or sclerotia) and, after
germination, they can deny them the nutrition needed to grow saprophytically to reach the root of
the host plant for infection. The second  feasible mechanism is the production by beneficial
microorganisms of substances that are antagonistic to the germination and growth of soil-borne
pathogens. The latter has been demonstrated under laboratory conditions with the microorganisms
in Lawn Restore.  Replicated studies conducted by Michigan State University over the past six years
with Lawn Restore, Green Magic, and Strengthen and Renew have shown significant reduction in
the amount of necrotic ring spot disease compared to the untreated controls.
    There are two general categories of products involved in the biological management of necrotic
ring spot. One category of products improves the thatch and soil environment to encourage higher
levels of beneficial microbial activity and the other adds the beneficial microorganisms to the thatch
and soil. Products developed by the Agro-Chem Corporation of Franklin Park, Illinois are in the first
category. Soil Aid is designed to flush thatch and soil of substances that are toxic to sustaining high
levels of microbial activity. It is an enzymatic type wetting agent. This treatment is followed by Green
Magic or Strengthen and Renew, which are products that contain major and minor nutrients as well
as plant and microorganism extractions. They have been shown to reduce the growth of L korrae
in laboratory culture work and increase natural microbial populations in the field. The use of Green
Magic or Strengthen and Renew have been shown, under field conditions, to allow existing necrotic
ring spot patches to recover and to prevent the development of new ones when used on a regular
    The Ringer  Corporation,  of  Minneapolis, Minnesota,  produces a  product in  the  second
category. It is an  organic fertilizer consisting of bone meal, feather meal, soybean meal, and other

protein sources. This is supplemented with Actinomycete fungi and bacteria in the genus Bacillus,
The product is called Lawn Restore. The microorganisms in Lawn Restore have been shown to
produce substances in laboratory culture tests that are antagonistic to L. korrae. Lawn Restore has
been shown to promote the recovery of necrotic ring spot patches and to prevent the development
of new ones under field conditions when used on a regular basis.

     Leptosphaeria korrae. the cause of necrotic ring spot in turfgrass, is a soil-borne pathogen
that  has been successfully  managed by the  use of beneficial microorganisms.  It must be
remembered that these products are not like fungicides that can be applied one time,  halting the
spread of the fungus and allowing the grass to  recover.  In order to  be effective, Lawn Restore,
Green Magic, and Strengthen and Renew must  be  applied on  a regular basis, either monthly or
bi-monthly, throughout the growing season to change the  biological makeup of the thatch and soil
                          POA ANNUA MANAGEMENT

     Poa annua (annual bluegrass) is composed of two types: Poa annua c.v. annua. a true annual
type, and Poa annua c.v. reptans. a perennial type. Both types are considered weeds in turfgrass
stands. P. annua is the number one weed problem on golf courses in the northern United States.
The annual type is managed mainly with pre-emergence herbicides, whereas the perennial type is
primarily managed by post-emergence herbicides like the arsenicals. Neither chemical has been
very successful in preventing the encroachment of FL annua into the species that were originally
planted, in addition, the arsenicals are highly toxic compounds that present a hazard to both people
and the environment.  Xanthomonas  campestris has been  successfully tested  under  laboratory
conditions for the management of EL annua. The bacterium infects the xylem tissue of the P. annua
plant where it interferes with the uptake of water and nutrients. The infected plants wilt and die from
the lack of water and nutrients. The bacterium is very specific for P. annua and all attempts to  infect
other grass species have been unsuccessful.  The new biological  control for the management of EL
annua will certainly be safer for people to use, to play golf on after application,  and safer for the
environment. Hopefully, it will be more effective in managing P. annua than the pesticides that are
currently being used.


     More precise models for the prediction of disease development are being  developed  today
because of  advancements in  computer technology and  weather-gathering  equipment.  Most
turfgrass diseases occur under certain environmental conditions, provided there is a susceptible
host and a virulent pathogen present. The environmental parameters are: air temperature, soil
temperature,  soil  moisture, leaf  wetness, and  relative humidity. Although  not all  of  these
environmental factors are involved in the development of every disease, at least two of them are
involved in ail disease development. Mathematical models to predict disease occurrence can be
developed by measuring these factors, recording them over a period of time, and correlating them
with disease  outbreaks.  These models can then be used to  make  more accurate  fungicide
applications  based on environmental  conditions, rather  than applying them on a calendar or
preventive basis.

     Most golf course superintendents would  like to apply fungicides at the most appropriate time
to achieve maximum disease control for the  least amount of money. This not only involves  the
money spent on fungicide, but labor cost to apply them, plus  the wear and tear on the  spray


equipment. Another consideration that has to be taken into account when applying pesticides is the
environment. No one wants to put more pesticides into the environment than necessary.

    These disease models were developed by collecting hundreds of thousands of data points,
analyzing them in various ways to determine which correlate best with disease development. This
would be impossible to do without the use of a computer, which is one of the reasons effective
disease prediction models  have only recently been developed. Once the computer analyzes the
data and it is determined which information is pertinent, a mathematical model is developed. This
prediction model is first tested under controlled environmental conditions in the laboratory where
appropriate adjustments are made. Then the prediction model is tested under field conditions for
validity. It usually requires a minimum of two seasons, with three being preferred.

    Once the model has been validated and any necessary corrections made, it is ready for the
end user. This can be a time consuming process if the data must be collected from several different
weather-measuring instruments, put into the formula and analyzed by the computer. However, if the
model is placed in a microprocessor that can record all the weather and environmental data, analyze
it and incorporate it into the model, then the task is much more quickly completed.

    Although this sounds like science fiction from the 21st century, this technology is here today.
Neogen Corporation's PestCaster has a Pythium blight model,  an anthracnose model, and an
annual  bluegrass seedhead-emergence model. This microprocessor will collect the weather
information,  assimilate it into the models, and indicate when it is necessary to make a fungicide
                        ANTHRACNOSE DEVELOPMENT

     Anthracnose,  caused by Colletotrichum graminicola. is a  devastating  disease  of annual
 bluegrass that can cause severe turf loss on golf course greens, tees, and fairways during the warm
 weather of July and August. To prevent this from occurring, golf courses normally treat their fairways
 three to four times a year on a preventive  or calendar basis to prevent the disease from occurring.
 However, depending on location, anthracnose does not occur every year, nor do out-breaks occur
 all season long every year. Sometimes anthracnose outbreaks only occur once during a two to three
 month  period in any summer. However,  without a reliable system to predict the occurrence of
 anthracnose, the golf course superintendent has little choice but to treat the greens, tees,  and
 fairways on a preventive or calendar  basis. The same can be said about fungicide treatments for
 Pythium blight.  It is too devastating a disease not to treat it on a preventive or calendar basis, unless
 one has access to an accurate predictive model. With these two models, fungicides can be applied
 only when needed, only when environmental conditions are present for disease development.  This
 will result in more accurate treatment of these two diseases, more  cost effective treatment of these
 diseases, and  less fungicides being  applied to ^environment. This mathematical model  was
 developed from over 150,000 individual data points. It has now been field tested for over six years.
 It has a 95% plus accuracy rate in predicting anthracnose outbreaks.

                            PYTHIUM BLIGHT MODEL

     The second model is for Pythium blight, caused by Pythium aphanidermatium. which can be
a devastating disease when it occurs. Pythium blight is a fast developing disease which can wipe
out the majority of the turf on a golf course in a 24-hour period if environmental conditions for disease
development are optimum. Because of this, most golf courses treat Pythium blight on a preventive
basis.  However, in many areas  of the United States  the disease does not occur every season.
Even in areas where it does occur every season, it does not occur all season long. But, in an attempt
to prevent Pythium blight from occurring and  to maintain their jobs, often  superintendents make
unnecessary applications  of fungicides. The use of the  Pythium blight model can  eliminate
unnecessary fungicide application, reduce the cost of treating for Pythium  blight, and reduce  the
amount of fungicides being applied to the environment. Other disease prediction models are being
developed for other diseases, which will allow turf managers to apply fungicides only as needed for
these problems as well. Hopefully, the day will come when all fungicides  are applied based on
disease models, which should reduce the cost of application by eliminating unnecessary treatments,
while giving  the desired level of disease control. This will also result in a significant reduction in the
amount of fungicides being applied to the environment.


     Root pathogens like k korrae and weeds like FL annua can now be  managed biologically.
Fungicides can be applied based on computer prediction models for diseases such as anthracnose
and  Pythium blight, which will reduce the amount of fungicides being put into the environment. The
turfgrass area has already made great strides in reducing fungicide usage and, hopefully, this trend
will continue in the future.

                             IN TURFGRASS:
                            M. G. Villani and R. J. Wright
                             Department of Entomology
                             NYSAES/Cornell University
                              Geneva, New York 14456
    The scarab grub complex attacks a variety of crops in the Northeast including turf and grassy
pastures, and woody ornamentals. The Japanese beetle, Popillia japonica Newman (JB), is the
most abundant and widely distributed species of the group, but other important species include the
European chafer,  Rhizotrogus majalis (Razoumowsky) (EC), Oriental beetle, Anomala orientalis
Waterhouse (OB), Asiatic garden beetle, Maladera castanea (Arrow) (AGB) and Northern masked
chafer. Cyciocephala borealis Arrow (NMC). All species cause considerable damage as immatures
and at least one, the Japanese beetle, causes heavy damage to a wide variety of agricultural and
horticultural crops through adult feeding (41 and citations within). Historically,  insecticides have
been the major control tactic used against these insects, however, because many of the plants
attacked by these grubs are grown in urban or suburban areas (golf courses, parks, home lawns
and gardens, landscaping around commercial buildings) the potential for human  exposure to
insecticides through  application or environmental  contamination is great. Pesticide contamination
of groundwater (from undetermined sources) has occurred in several areas of the Northeast (e.g.,
aldicarb, oxamyl and carbofuran on Long Island) and there have been instances of bird kills
associated with use  of diazinon on golf courses. Effective long-term  control of the scarab grub
complex was achieved with  organochlorine and cyclodiene insecticides until their use was
discontinued through insect resistance and government intervention; less consistent control has
been achieved with  organophosphate and carbamate insecticides (2, 45) and with a variety of
biological agents (nematodes, fungi, bacteria and viruses) (27,46, 49).

    One reason for this inconsistency may be the lack of basic understanding in the interaction of
the control tactic (chemical, biological or genetic), the  cropping system, the target insect, and the
soil physical and biotic environment (soil moisture, temperature, texture, compaction, and microbial
flora etc). While each of these factors has been independently studied to varying degrees by basic
and applied researchers, their interdependence has largely been ignored.  If we assume that a
combination of management tactics (IPM) will be required to effectively and safely manage scarab
grubs in turfgrass in the future then the nature of specific interactions between target insect
population(s),  control agent(s) and the soil environment must be examined. In this chapter we will
focus on the management of the scarab grub complex in turfgrass and discuss how 'ecological'
approaches to this problem may help control scarab grubs more effectively.

                            SCARAB GRUB BEHAVIOR
     C. R. Harris in reviewing the problems of controlling soil insects with insecticides in general
(21) and soil insects in turf in particular (22) suggests:

     "During the  past 20 years this problem (lack of efficacy of short residual insecticides in
     controlling soil insects) has received considerable attention and a number of factors have
     been shown to influence insecticide  activity in the soil including: the physiochemical
     properties of the insecticide; soil and climactic factors; insect susceptibility to insecticides
     and insect behavior in the soil...a factor that has received little attention, other than  in a
     very general sense, is the way  insect behavior will influence the effectiveness of soil
     insecticides...for the immediate future, the most promising research possibilities are in the
     area of soil insect ecology. With greater comprehension of the factors influencing the
     behavior  and development of soil insects, it would be possible to utilize insecticides far
     more effectively"

     Much  of  the available literature  on the impact of soil physical properties on the movement
behavior of members of the scarab grub complex has recently been reviewed by Tashiro (41 and
references within [1, 8, 11,12, 14, 15,  16, 17, 18,  19, 20, 24, 25, 35, 37 ,38, 43]) Although  previous
research has often been qualitative or anecdotal some interesting patterns do emerge. Briefly we
would like to outline what  is known about five species  of scarab grubs (JB, EC, OB,  NMC, AGB)
which are of major economic importance in the Northeast  and share similar life history  patterns. All
five species have somewhat similar seasonal patterns  of vertical movement of grubs  in response
to  gross temperature changes.  After  hatching, larvae  feed  at or  near the  soil surface  from
mid-summer to  late fall.  As surface temperatures  cool grubs  migrate down into the  soil and
overwinter as  late instar larvae below  the frost line. In the  spring grubs migrate back to the surface
again in response to temperature changes, complete feeding and  move down again  into the soil
profile to pupate and eclose. Field observations  indicate that EC grubs remain at the  soil surface
later in the fall  and return to the soil surface earlier in the spring than  do the other four grub species.
Confounding this yearly temperature  moderated movement pattern there may be more  localized
response to changes in soil moisture as well. Grubs have  been reported to move deeper in the soil
in response to decreasing soil moisture. Most of the observations concerning response to  moisture
are anecdotal. Even under 'favorable conditions' of soil  moisture  and temperature, field reports
indicate that different grub species tend to be found at different soil levels; for example, EC and
AGB tend to feed further below the soil surface than  either JB  or OB grubs.  The differences in
preferred feeding depths of different  grub species have an effect on the types of plant tissues
attacked. Grubs such as the EC, which feed for a longer period of time, have  a greater  potential
effect per grub than do other grub species that leave the  surface earlier in the fall and return later
in the spring.  AGB are normally less  destructive than  JB or OB grubs to turf, in part due to the
tendency of these grubs to feed at greater depths which  results in  less damage (however due to
their  greater depth  AGB  may be much  more difficult to manage  with  non-mobile  chemical

     Information concerning the behavior of soil  insects is anecdotal in most instances due to the
difficulty in studying insect behavior under 'natural' conditions. There is a general perception that
such research, if not impossible, is difficult, tedious, and  cost ineffective when compared with similar
studies of above ground insects. This attitude toward soil insect research has resulted in a situation
where the soil ecosystem  is treated as a 'black  box' in which the  consequences  rather than the
processes of insect behavior are measured. While there have been many  studies looking at the
movement of soil insects over long periods of time (3, 4, 5, 7,  10, 13,, 23, 29, 30, 31,) the studies


tend to lump the soil insects found in the top 5 cm as being at the surface layer. It is clear from
insecticide movement studies in turfgrass systems that the details of grub movement within the top
5 cm over relatively short periods of time can have a profound effect on management.

     Villani and Gould (44) have developed an x-ray technique that makes it possible to study soil
insect movement and behavior within heterogeneous soil blocks.We have expanded this technique
to include studies with several species of scarab grubs in larger arenas (up to 35 cm by 12 cm by
43 cm) and with field-collected soil blocks. Soil blocks retain their field characteristics (compaction,
heterogeneity, endemic floral and faunal communities) and therefore allow for the careful monitoring
and manipulation of the system for long periods of time. During the past year we have been gathering
data from both simulated field soils (soil profiles created in the laboratory through the use of a variety
of field soils) and actual field soil  blocks extracted from turfgrass pasture plots (see 47 for details
of experimental design and analysis for studies concerning radiographs outlined below).

     Work in our  laboratories with radiography indicates there is a species-specific response of
scarab grub species to changes in moisture and temperature in the  soil profile (47). These studies
simulated the effects of irrigation and drought and temperature flux on populations of several scarab
grub species. NMC, JB and OB and EC grubs all showed a strong trend for moving downward into
the soil profile as  soil moisture declined at the soil surface and turf root zone and movement back
to the root zone when irrigated with the equivalent of 1 cm. of distilled water; EC grubs exhibited the
least sensitivity to drying soil which may be related to their  ability to rapidly escape from extreme

     There were  significant differences among  grubs (EC, JB, and OB)  in their responses to
fluctuating temperatures. Shifts in soil temperature (decreasing from 20  to 5 C over 5 week period)
had very little impact on the position of EC grubs. This relative unresponsiveness to temperature
flux conforms to field observations (41, M. G. V. personal observations) which indicate that EC grubs
are often found in the turf root zone well into early winter and early spring, and at times feeding In
the root zone under snow if this zone is not frozen. In contrast,  there was a marked response to
shifting temperatures with the other two scarab species. JB grubs fed in the root zone in the stable
temperature regime (constant 20 C) while in the shifting temperature regime grubs moved from the
root zone downward with the  onset of cooling soil (14 C) and returned  to the surface as temperatures
increased back up to 20 C. OB grubs appeared more variable but there was a clear population trend
for grubs to remain at the root zone in the stable treatment (constant 20  C) and to respond to lower
 soil temperatures (8 C) by  moving down into the soil profile . An  increase in  soil temperatures
appeared to move a portion of the OB grub population back to the root zone while not affecting the
median population value.

     These studies demonstrate species-specific differences in scarab grub response to changing
temperature and  moisture conditions in simulated turf systems which conform to reported  field
reports. These differences  involved  both changes  in the population median and the overall
population distribution. Increased knowledge of species-specific movement patterns of scarab grubs
in turfgrass in response to these and other soil environmental factors will have practical applications
in developing more effective management systems for these  soil insects in that they will  help
determine the probability of overlap of a specific grub species with a  specific control agent in space
and time, suggest depth  to which sampling for grubs must  occur in sampling  and monitoring
programs and indicate the 'hidden1 population of grubs when sampling within the turfgrass root zone.

     Understanding the behavior of soil insects found in turfgrass is important considering the
difficulty in moving soil insecticides down into the root zone of established turf. Physical factors that
result in the movement of target insects as little as 1 cm into the soil profile may put these insects
out of the effective active zone of chemical and biological control agents. Conversely, highly mobile
soil insecticides will move beyond the root zone and will again be ineffective in controlling soil insect.
Several studies (39, 28, 33) have  shown that, unlike the cyclodiene soil insecticides, the less
persistent organophosphate and carbamate  insecticides  degrade quickly,  leaving little time for
movement  into the soil and roots. Diazinon applied to turf degrades so rapidly that < 1% of the
original concentration is present in the root  zone  14 days after treatment (39). Chlorpyrifos is
considered one of the more persistent OP insecticides but Kuhr and Tashiro (28) found < 1% of the
original concentration of this pesticide could be recovered from the thatch-root zone 56 days  after
application. These results indicate that there is a relatively narrow window in which turf insecticides
can be applied to  obtain consistent control.  Niemczyk (32, also  33,34) reports that virtually no
insecticide  applied  to turf for scarab grub control actually  reaches the soil surface if appreciable
levels of thatch are found at the surface. The generally low persistence, low solubility and  high
organic binding properties of soil insecticides labelled for turf insect control have led to a situation
where soil insecticides may not be reaching the target population in the field.

     It has been noted that soil insecticides are more effective in controlling scarab grubs in turfgrass
when they are irrigated into the soil with at least 1 cm of water. It has been assumed that this irrigation
helped move the active compound off the turfgrass and from the soil surface to the root zone where
scarab grubs were feeding. Recent studies by Niemczyk (32) and Niemczyk et. al (34) suggest that
little if any  active material is moved into the soil through irrigation. A study (see 47  for detail on
experimental design and analytic procedures) reviewed below, proposes an alternative hypothesis
to explain increased insecticide efficacy with the use of irrigation: irrigation moves scarab grubs up
to the surface rather than moving the insecticide down to the grubs in the soil profile.

     Studies were conducted in plexiglass arenas (35 cm by 5 cm by 43 cm) filled with sieved loamy
sand soil. Arenas were seeded with grass seed and ten third instar EC grubs were placed at the top
of each arena; grubs which did not dig  into  the soil within 1 h were replaced. There were eight
replications of each of the following treatments:
         Treatment          Isofenphos (Oftanol 1.5G)           Amount of water added

              1            2.24 kg (Al) per ha                 50 ml {= 0.33 cm irrigation)
             2            2.24 kg (Al) per ha                 150 ml (= 1.0 cm irrigation)
             3            none                           50 ml
             4            none                           150 ml
    Arenas were x-rayed at 0,24, 96,166, and 360 h posttreatment. Residue samples were taken
at 24 h posttreatment from additional infested and treated arenas receiving treatments 1 and 2.

    Grub condition  (normal, moribund or dead) and location (depth below soil surface) was
recorded at the end of the study (360 h posttreatment). Soil moisture was measured gravimetrically
at this time by taking  samples at intervals through the soil profile from all arenas. Residue samples
were taken from the soil surface and at intervals through the soil profile of treated arenas and
analyzed by standard analytic procedures.

    The results indicate that there was little movement of insecticide past the 0-2.5 cm level of
soil regardless of the irrigation  applied (Table  1). There was a significant loss of active material
(percent recovered) in the high moisture treatment after 360 h when compared with the dry condition.
A significant portion of the insecticide recovered remained on the soil surface unavailable for insect
control in both treatments. Percent control was identical in both treatments after 15 days. However,
there was a higher proportion of morbid grubs  in the higher moisture treatment; morbid grubs will
die within 14 days in most cases (M. G. V., unpublished data). These results confirm that insecticides
are not moving into the profile in response to simulated irrigation and suggest that grub  mortality
will be higher in high  moisture plots despite lower total insecticide recovery.

     Figure 1 shows  the shift in the soil moisture profile for the high and low moisture treatments
over the duration of the experiment. Twenty-four h after water was added to the low moisture arenas
the percent moisture  in the soil profile remained fairly uniform with a slight (but important) rise in the
first 2.5 cm; the soil continued to dry up to 360 h when a strong moisture gradient was observed.
Twenty-four h after moisture was added to the high  moisture arenas there was a strong trend for
decreased moisture with increased soil depth. Soil moisture remained uniformly high but there was
a slight (but important) drop in the top 2.5 cm of soil. Data on grub position in each  treatment (Fig.
2) were grouped at levels which are important with regards to the observed pesticide movement in
the arenas (Table  1); 0-2.5 cm deep (high insecticide concentration), 2.5-5 cm and greater than 5
cm (no insecticide detected [< or equal to 045 ppm]). The following points can be made based on
these data. First, addition of water brought grubs to the surface in all treatments  (data at 24 h).
Second, the  activity  of the insecticide (as indicated by the  general lack of grub movement  in
response to changing soil factors when compared with non-treated boxes) becomes  apparent in
both moisture regimes between 96 and 166 h. There is  a slight difference  in grub population
distribution within moisture regimes between control and treated arenas. Third, differences in grub
population distribution between moisture levels in the control  arenas begin to occur at 96 h ; i.e.,
grubs in low moisture control arenas begin to move down in the profile while those in high moisture
regime remain near surface, potentially in contact with insecticide. And finally, grubs in high moisture
control plots begin to respond to a slight decline in soil moisture at 166 h. Note that moisture levels
at 360 h in these arenas are greatest in the greater than 5 cm level. Clearly soil moisture flux within
the profile had a profound effect on both insecticide persistence and EC grub movement  patterns
in this study and these effects influenced the efficacy of isofenphos in the soil.

                           TURFGRASS INSECTICIDES

     Many factors, including soil pH, organic matter, moisture, thatch, insect behavior and microbial
degradation of insecticides influence the efficacy of currently registered insecticides, (6,21,22,28,
33, 36, 42 47 48). One factor contributing to the variable control of scarab grubs in the field is the
presence of mixed-species populations of grubs, which may exhibit species-specific insecticide
susceptibilities. Although field insecticide efficacy studies against mixed populations of scarab grubs
have been reported  (e.g.,9,  50), significant  treatment effects can be demonstrated  only for the
most abundant grub  species,because  secondary species are often present  at low densities and

their distribution is patchy. Previous work by Baker (2) has demonstrated among- and within-species
variation in  susceptibility of New York populations of Japanese  and Oriental beetle larvae to
chlorpyrifos, bendiocarb and isofenphos. Additional research in New York State (45) was done to
provide more information on the susceptibility of three economically important scarab grub species
to five  currently labelled turf  insecticides  (diazinon,  chlorpyrifos, isofenphos, bendiocarb and
ethoprop). This laboratory study indicated that, in general, EC grubs  are less susceptible to soil
insecticides  than the other two scarab grub species (Table 2). This finding agrees with reports from
extension agents and turfgrass and sod producers in New York State. Several statistically significant
interactions  were found which  indicated the need to study each species-insecticide combination
separately. The most striking insecticide - scarab grub species interactions involved diazinon and
chlorpyrifos. Diazinon provided good control of OB and EC grubs, but very poor control of JB larvae.
However, chlorpyrifos provided good control of JB and OB, but very poor control of EC grubs. Since
behavioral differences among grub species (i.e., their characteristic position in the soil profile in the
field which  may  influence  exposure to  insecticides) have been  eliminated in  these studies,
differential mortality of JB and EC grubs to diazinon and chlorpyrifos may reflect species-specific
tolerances to these compounds  (if testing of  additional populations give similar results) or localized
insecticide  resistance. The  relatively low  level  of mortality observed with all grub species in the
isofenphos treatments may be attributed  to a number of causes including: loss of activity of the
compound through microbial degradation  due to an 'activated'  test soil, insufficient initial product,
and insufficient time for  mortality to be apparent;  discrimination tests undertaken in future studies
should  be done with  higher rates of this product. Ethoprop treatments induced uniformly high
mortality with all scarab grub species tested indicating either similar tolerance to this material or
application rates too high for discrimination among species.

     The results of these  studies indicate the  need to  develop species-specific  insecticide
recommendations for the scarab grub complex, and to encourage those responsible for insecticide
use in turf to be aware of the scarab grub species present in their areas. Although single species
infestations  occur in some areas of New York, mixed  populations of JB and EC grubs (western
section of state) or JB and OB grubs (Long Island) and other scarab grub species are the rule rather
than the exception. Our results suggest that, with some insecticides (e.g., diazinon and chlorpyrifos),
intermediate levels of control of the overall scarab grub population may reflect high mortality of one
species and little or no  mortality of one or  more co-existing species.  Depending  on the relative
abundance of each species at a given site, percent control achieved with each insecticide may vary
widely. Differences in insecticide susceptibility among species of the scarab grub complex need to
be  considered, as  well as  the possibility  of  insecticide resistance, microbial degradation, or
inadequate  application  procedures, as a possible reason  for control failures  after use of turf

     Development of biological  controls for soil insects such as scarab grubs would provide an
alternative to the use of chemical insecticides and would alleviate many of the problems associated
with insecticide use (development of insecticide-resistant pest strains, environmental pollution).
We have found it useful to group pathogenic agents used to control soil insects in turf based on
their mobility and their reproductive behavior.  The first  are agents that  interact  with the soil
environment and the target species much like a soil insecticide, an example of this type of agent is
Bacillus thuringiensis (Bt) toxin. The material is non-mobile (passive movement through profile only)

and non-replicating, therefore contact between toxic agent and target insect is determined by
passive movement of the agent and activity of the target. The second class of control agents are
those that are  non-mobile  but  replicating (e.g.  Bacillus popilliae.  Beauveria bassiana  and
_Metarrhizium anisopliae). Unlike soil insecticides and Bt, the behavior of the target insect is vitally
important to the spread of the pathogen: infected grubs, which respond to environmental conditions
and/or pathogen induced aberrant behavior, may  move the control agent out of the range for
effective control  by moving the site of agent replication outside of the normal range of the target or
the optimal range of agent replication. If for example scarab grubs infected with milky disease move
down into the soil profile  in response  to environmental conditions and then  die, this movement
would effectively reduce milky disease spore levels from the upper soil profile. Since it is only in the
upper profile that grubs would be actively ingesting spores (needed  for infection) and where soil
temperatures  are sufficient for spore  replication (see 41) this movement would effectively  halt
significant disease spread and insect control. Finally, there are those agents that are both mobile
and replicating such as entomogenous nematodes (e. g. Steinernema feltiae) which have been
discussed  at  length in  previous  chapters  of this book (insect parasites and predators can be
generally included in this third class of agent). These agents are interesting ecologically because
infection and replication depend on the interaction of the soil environment on both agent and target.
 Initial infection and subsequent spread through the  target population depends upon the overlap of
 agent and target in both space and time within the  soil environment.  We believe that this class of
 control  agent  has great potential  for controlling soil insects when incorporation of control agent is
 not possible (47, 49).

     The relative lack of success in predicting scarab grub damage in turfgrass and the costs
 involved in achieving satisfactory control dictates a more systematic and comprehensive research
 effort. Paramount to such an approach is the ability to monitor grub response to static and dynamic
 soil factors and to manipulate these factors to determine changes in insect response. Understanding
 the fundamental differences in behavioral response among the  various grub species within the
 complex to a variety of typical soil factors will enhance our ability to predict the stress  each species
 will inflict in turf and other horticultural plant species.  An understanding of the  interaction of the
 control agent (biological or chemical),with the target insect species and with the soil environment
 will lead to changes in current management practices which will allow for greater overlap in agent
 and target leading to a greater potential for effective management.


                                      TABLE 1
    Residue analysis and effect on EC larvae of surface applications of isofenphos (Oftanol 1.5G)
under two different moisture regimes.
Isofenphos residues
EC larvae
Treatment Time Depth





(h) (cm)
24 0-2.5
24 0-2.5
360 0-2.5
360 0-2.5
% Recovered %on surface


65.25 47.38

26.75 47.53

% Control % Normal

28.4 56.8

28.4 33.3

    3/ ND = non-detectable (< 0.045 ppm).

    Source: Vfflani and Wright (1988b)

                                        TABLE 2
     Efficacy of five turf insecticides against last stage larvae of three scarab grub species in a
 laboratory soil bioassay; insecticides were incorporated into soil at one-half labelled rates. Analysis
 of variance of percent control (angular transformed) of grubs after five weeks indicates significant
 differences among insecticides (df=4, F= 13.201, P < 0.001) and grub species (df=2, F=6.066, P <
 0.01). There was also a small but significant insecticide by grub species interaction (df=8, F=3.255,
        Treatment           	Percent Mortality
                                  QB                 JB                 EC
        Chlorpyrifos              74                 91                  21
        Bendiocarb                75                 70                  37
        Ethoprop                 100                99                  95
        Diazinon                  93                 25                  78
        Isofenphos                26                 38                  11

        Source: Villani et. al. 1988

                                     FIGURE 1
    Soil moisture profile for high and low moisture treatments at beginning and end of study of
interaction of soil moisture and isofenphos persistence and efficacy against scarab grubs. Histogram
bars indicate (left to right) % moisture at the 0-2.5, 2.5-5.0, 50.-7.5, 7.5-15.0,  15.0-22.5  and
22.5-30.0 cm soil depths.
                                 LOW MOISTURE
                                                                D  9-12
                                 HIGH MOISTURE
                                                                D  9-12

                                         FIGURE 2
       The distribution of EC grub populations in arenas maintained at high and low moisture levels
  with and without addition of isofenphos to the surface. Histogram bars indicate (left to right) percent
  of EC population at the 0-2.5, 2.5-5.0 and greater than 5.0 cm depth.
           24    96   166   360
                                   • 0-1
                                   D 1-2
                                   E3 >2
                                     • 0-1
                                     n 1-2
                                     E3 >2
            24     96    166    360

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        Pesticides Program, College of Agric. and Life Sciences, Cornell University, Ithaca N. Y.

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        to European chafer grubs. J. Econ. Entomol. 71:904-907.

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                          FROM TURFGRASS
                        A.J. Gold, W.M. Sullivan, and RJ. Hull
            Departments of Natural Resources Science and Plant Sciences
           Contribution Number 2445 From the Rhode Island Agrlc. Exp. Sta.
                             University of Rhode Island
                                Kingston, Rl 02881

    Nitrogen constitutes the largest chemical  input routinely applied to well maintained turf.
Nitrogen fertilizers are applied in a variety of forms, ranging from slow release types, such  as
methylene urea, to quick release  formulations,  such as ammonium nitrate. Regardless of the
formulation applied, nitrogen not taken up by growing plants or soil microorganisms is readily
transformed to nitrate-nitrogen. Figure 1 summarizes the nitrogen cycle in a turfgrass environment.
Nitrate-nitrogen is a mobile anion that has the potential to move rapidly from the rootzone to the
groundwater. Percolation of water from the rootzone is the major pathway for water discharged from
turfgrass (Morton et al. 1988). Several researchers have found that selected fertilization and
irrigation practices can generate substantial leaching of nitrate-N from the rootzone of turfgrass
(Owen and Barraclough, 1983;Rieke and Ellis, 1974; Morton et al., 1988).

    Nitrate-N is a drinking water contaminant with a U.S. Drinking Water Standard of 10 mg/L
(USEPA, 1976). Nitrogen inputs to coastal bays and estuaries, such as the Chesapeake Bay, have
been found to accelerate eutrophication. Water quality degradation can result from concentrations
of nitrogen much less than the drinking water standard of 10 mg/L (Ryther and Dunstead, 1971).

    Various turfgrass management strategies have been evaluated for their capacity to reduce
nitrogen leaching losses from turfgrass. In this chapter, several options will be highlighted:

    • Nitrification inhibitors to slow the formation of the mobile nitrate anion.

    • Irrigation scheduling to reduce leaching to groundwater.

    • Fertilizer source selection to minimize the  pool of nitrate in the rootzone.

    • Fertilizer application rate and timing to optimize plant uptake.

    Our discussion will concentrate on practices typically used to manage home lawns or turf used
for outdoor recreation.

                         NITRIFICATION  INHIBITORS

    Most nitrogen fertilizers and all natural processes of organic matter cycling introduce nitrogen
into the soil solution in the ammonium form (Figure 1). This reduced cationic nitrogen is immobilized
on cation exchange sites in  the soil and readily absorbed by microorganisms and plant roots.
Consequently, ammonium is not readily leached from the soil even when appreciable hydraulic flux


occurs. Hesketh (1986) generally found less than 1.0 mg/L of ammonium-nitrogen in the soil solution
collected in suction lysimeters from the root zone (20 cm depth) of Kentucky bluegrass turf. At the
same time, soil solution nitrate-nitrogen often exceeded 20 mg/L. It appears that if the transformation
of fertilizer nitrogen to nitrate-N could be inhibited and nitrogen retained in the ammonium form, the
potential for nitrogen loss through leaching would be minimized.

     In field  crop production,  nitrification  inhibitors have been  used  successfully to stabilize
ammonium-nitrogen and increase nitrogen use efficiency (Huber et al. 1969; Prasard 1976; Warren
et al. 1975). In these studies, the inhibiting compound was mechanically incorporated into the soil
usually with the nitrogen fertilizer. Nitrification inhibitors used to improve the nitrogen use efficiency
of turfgrass  have yielded few positive results. Waddington et al. (1975) found no benefits  from
including  the  nitrification  inhibitor nitrapyrin  (2-chloro-6-(trichloromethyl) pyridine)  with nitrogen
fertilizers  applied to turf. Hesketh (1986) evaluated nitrapyrin at two rates, terrazole (3-ethoxy-3-
trichloromethyl-1,2,4-thiadiazole) and DCD (dicyandiamide) for their ability to enhance nitrogen use
efficiency in urea-fertilized Kentucky bluegrass turf. Turf quality,  clipping yield, clipping nitrogen
content, and the nitrate and ammonium concentration  in soil water were  measured.  No consistent
evidence of  improved nitrogen uptake was obtained when nitrification inhibitors were present.

     In these studies, fertilizers and inhibitors were applied to the  surface of turf and washed into
the sod with irrigation water. No mechanical incorporation of the inhibitors into the soil was attempted
nor has any practical way of accomplishing this in established turf been proposed. Because nitrogen
leaching appears to be minimal on urea fertilized turf (Hesketh, 1986; Hull et al., 1987; Morton et
al., 1988) nitrification inhibitors may not generate substantial effects. However, because there was
no  evidence of delayed nitrification when urea was applied  with  an inhibitor,  Hesketh  (1986)
concluded that the  inhibitors probably were adsorbed in the overlaying thatch and never reached
the soil depths where nitrification was most active.

     To determine if nitrification inhibitors can be effective in stabilizing ammonium-nitrogen when
nitrogen fertilizers are applied at the time of turfgrass seeding, nitrapyrin and DCD were disked into
the soil along with urea just prior to seeding Kentucky bluegrass (Hull et al. 1988). All parameters
measured exhibited a beneficial response to DCD, applied alone or combined with nitrapyrin, but
no response from nitrapyrin was noted. The nitrogen recovered in late season turfgrass  clippings
doubled  in response  to DCD incorporation but this constituted only 10 percent of the fertilizer
nitrogen applied. It appears that the potential for nitrate leaching at the time of turfgrass seeding is
significant. However,  it can be reduced somewhat by incorporating a water soluble nitrification
                             IRRIGATION SCHEDULING

     The potential for off-site nitrate-N losses depends on the concentration of nitrate in the rootzone
and  the frequency and quantity of water percolation through the soil profile. Irrigation has been
shown to significantly increase nitrate-N leaching  (Snyder et al., 1984; Endelman  et al., 1974).
Morton et al. (1988) found that overwatering increased nitrate nitrogen transport to the groundwater
six fold from turfgrass, independent of fertilization rates.  Home lawns are typically watered with little
regard for soil moisture status or the water holding  capacity of the  soil.  Where irrigation is
automatically controlled with timers on  permanently installed systems, rates are often selected to
meet maximum evaporative demands, regardless of weekly rainfall and climatic conditions (Snyder
et al., 1984). Excessive watering will increase antecedent soil moisture, thereby promoting additional
leaching from natural storm events or from the supplemental water alone.

    Supplemental water should be added judiciously in metered quantities to avoid drought stress
and to reduce losses from the rootzone to the groundwater. Efficient scheduling of irrigation water
requires an understanding of soils, plant physiology, and meteorology. Several  approaches are
used to determine when turfgrass is in need of irrigation:
    • Direct measurement of soil moisture status,

    • Direct measurement of plant water status, and

    • Estimation of cumulative evaporative demand from evaporation pans or climatic data.

    Soil moisture  measurements can be obtained with inexpensive tensiometers placed 7 to 15
cm into the rootzone. In  a given climate, plants have  been found to exhibit drought stress at the
same soil moisture tensions, regardless of soil texture. As soil dries the soil water tension increases.
At a predetermined "critical tension" irrigation is initiated.  Studies relating drought stress to soil
moisture tensions have been performed on a  range of turfgrass species. In a  greenhouse
experiment, Aronson, et al. (1987) found that fine-leaved fescues could maintain acceptable quality
at tensions greater than 1 bar, while Kentucky bluegrass quality was found to decline markedly after
the soil had reached 0.6 bars. To reduce unneeded irrigation and avoid drought injury, additional
research is required to  establish critical tensions for other turfgrass and grass mixtures.

     Recently, Throssell et al. (1987) have suggested monitoring canopy temperature with an
infrared thermometer to  detect plant water stress. Several researchers  have found  that canopy
temperature  in  turfgrass increased in  response to drought stress.  Other researchers  have
established the relationship between evapotranspiration from well watered turfgrass and moisture
use predictions based on climatic measurements (Aronson et al. 1987; Pochop et al.,  1977). Daily
tabulation of the expected water loss along with soil moisture characteristics of a particular site can
generate estimates of soil moisture status and critical tensions.
     Determining the appropriate depth of irrigation is essential to avoid excess water draining from
the rootzone. The proper application depth of water requires knowledge of the upper and lower
limits of the available water in the soil and the depth of the rootzone. The lower limit of available
water in the soil  is the amount that can be extracted from the rootzone by turfgrass before drought
stress occurs.  Field capacity, the upper limit,  is the soil water content that  occurs after all
gravitational water has drained from a previously saturated soil. Ideally, enough water should be
applied to bring the entire rootzone to field capacity without promoting percolation. Since cultivated
turf has a shallower rootzone  than commonly irrigated field crops, drought stress may occur earlier
in turf, while percolation  from the rootzone could occur from the application depths used in field
crop irrigation. Most of the data necessary to develop recommended application depths is available;
however, the information needs to be evaluated and tailored to turfgrass.

                        FERTILIZER SOURCE SELECTION

     Synthetic fertilizers, manures, animal and plant  residues,  by-products and a host of other
materials can supply nitrogen to  the turfgrass plant. The requirement for continued  access and
utilization of turf requires that turfgrass fertilizer products  be easy to handle, of uniform quality,
inconspicuous after application, readily effective,  and impart no offensive odor. The general visual
and  functional  expectations  of  modern turfgrass management practically  eliminates  use  of
non-processed  fertilizer  materials  (Beard,  1973).  The choice of  one fertilizer over another
traditionally has been  based on turfgrass performance ratings (Waddington and  Duich 1976;
Wilkinson 1977; Nelson 1980). More recently, nitrogen loss to the environment has been considered
(Snyder et al. 1981; Wesely et al.  1988)

     Turfgrass  management  practices employ  N fertilizer products that  belong to  three general
classes. They are the synthetic inorganic, synthetic organic and natural organic nitrogen sources
(Table 1). The differing properties of nitrogen containing fertilizers determine where  and when the
fertilizer N enters the soil nitrogen cycle (Figure  1).

     Turfgrass  fertilizer management ideally provides plant available nitrogen in the soil solution
as plant demand arises.  Turfgrasses absorb most nitrogen as nitrate, however ammonia which is
less abundant in the soil  solution is also absorbed. The three classes differ in the rate at which the
applied N becomes available to the growing plant. The transformation of the fertilizer product to
absorbed plant nutrient may involve only dissolving the fertilizer product in soil water or it may be
dependent on exacting soil water, aeration, temperature and microbiological conditions (Hays and
Haden, 1966).

     The concept of nutrient release period refers to the rate with which the fertilizer increases the
ammonium and nitrate concentration in the soil solution. The 'fast' or 'quick' release products are
generally soluble salts and contain N in the ammonium or nitrate form at application.

     The 'slow' or 'controlled' release fertilizer products require additional physical, chemical and/or
biological processing after application for the nitrogen to reach the water soluble form required for
plant utilization. These products range from urea and urea solutions to sulfur or resin coated urea
to complex polymers of urea and formaldehyde. Barriers to solubilization and transformation are
achieved through a number of different methodologies. Nitrogen release and transformation of these
products will vary with the polymer  length, coating thickness and integrity, and the environmental
conditions into which they are placed. Sulfur coated urea and similar coated products such as
OsmocoteR, have coatings of limited or reduced permeability that restrict the movement of water
and nutrient  from the granule. Methylene urea  and  urea formaldehyde are low molecular weight
compounds that  require  microbiological  activity to mineralize the nitrogen. IBDU (isobutylidene
diurea) has controlled release properties  due to its chemical structure and the particle size of the
product used. These 'slow' release synthetic organics produce their metered solubility characteristics
and reduced nitrification  rates via different  mechanisms.  The methylene-ureas, IBDU and SCU
products have  solubility  characteristics that are inversely proportionally to molecular weight and
granule size (Hays and Haden, 1966; Hughes, 1976).

     The major source of the natural organic fertilizer class is activated sewage sludge. The best
known product comes from the Milwaukee municipal system and is called MilorganiteR. Milorganite
and comparable materials contain the nitrogen in complex organic molecules. The rate of N release
is dependent on the microbiological activity in the soil. The predominant factor influencing N release
from this fertilizer class is soil temperature and aeration. The rate  of N availability to the plant is
regulated by soil temperature  as it  effects mineralization  and subsequent nitrification by soil

     The N in synthetic inorganic products,  for  example, ammonium nitrate, calcium nitrate, and
ammonium sulfate, is water soluble, rapidly available to plants and highly susceptible to leaching.
Synthetic inorganic N fertilizers have generated excessive N losses to the groundwater (Bredakis
and Steckel,  1963; Brown et al. 1977; Snyder et al. 1981). Nitrate-N concentration up to 200 mg/L
and total losses of over 15 percent  of the applied fertilizer have been reported from turf fertilizers
with synthetic inorganic N (Brown et al. 1977).

     In contrast to synthetic inorganic fertilizers, the  natural and synthetic organic products have
been found to generate very low N losses  to the groundwater. Bredakis and Steckel (1963), Snyder
et al. (1981), Starr and DeRoo (1981) and Brown et al. (1982) all document limited  release of
nitrate-N from synthetic organic product used in the turfgrass environment. The highest nitrate-N

concentration leaving the  turfgrass rootzone were 2 and 18 mg/L when ureaformaldehyde and
activated sewage sludge were applied in a study conducted by Brown and colleagues (1977).

    The most common nitrogen form now used for turfgrass fertilization are the synthetic organic
products. Urea is the most common N source of the synthetic organic class. Turfgrass response is
excellent and off site losses are low when urea is used as the N source. Mean annual nitrate-N
concentration below the turfgrass rootzone  following urea  application never exceed 6 mg/L in
studies conducted by Morton et al. (1988) or Wesely et al. (1988).


     Unlike field crops, annual fertilizer applications to turfgrass can be easily split and applied in
small increments throughout the growing season. In the Northeast U.S., commercial lawn care
companies almost exclusively use urea or urea formaldehyde as the nitrogen source. Applications
may occur monthly, from late spring through late summer, with a final large application in late fall.
Morton et al. (1988) found no evidence of increased nitrate-N  leaching following late fall or late
spring applications  of urea/urea formaldehyde. In the late  fall, the cool temperatures slow the
enzymatic hydrolysis of urea to ammonium and the subsequent biological oxidation of ammonium
to the mobile anion nitrate. Plant uptake may match the generation of  ammonium and nitrate,
 reducing the pool of teachable N in the rootzone. More research is need to define the  relationship
 between the rates of nitrate production and uptake by roots. The lack of nitrate-N in soil leachate
 following late spring applications of urea may result from the vigorous turf growth that occurs during
 this period. Plant uptake may be well suited for absorbing moderate nitrogen applications at this
 time of year. Again, we believe research on turfgrass nutrient budgets is essential to fully understand
 this situation.

     Morton et al. (1988) observed high concentrations of nitrate-N in soil water leachate following
 late summer applications of urea. Cisar (1986), through analysis of leaf growth and N content of
 clippings, found that N uptake by Kentucky bluegrass declined in late summer. Applying nitrogen
 fertilizer when plant uptake is reduced could generate excessive amounts of soluble nitrogen in the
 rootzone and could  increase the potential for waterborne nitrogen losses from the rootzone.

     A dense turfgrass sod constitutes a substantial sink for topically applied synthetic organic
 nitrogen. This was dramatically demonstrated by  Hull et al. (1987) when urea was applied as a
 single treatment at 288 kg N/ha to five turfgrass species during mid-May. Over the next four months,
 the nitrate-nitrogen  content of soil water collected at a 60 cm  depth never exceeded 1.0  mg/L.
 During the growing season, less than 0.4 kg N/ha leached from these plots while 58 percent of the
 applied nitrogen was recovered in clippings.

     However,  the  soil water from Kentucky bluegrass plots which had received over 350 kg
 N/ha/year as urea for 14 years sometimes contained more than 10 mg N/L below the root zone and
 more than 50 mg N/L within the rootzone (Hesketh, 1986). At this high fertility level, approximately
22 kg N/ha were lost through leaching during the growing season which was equivalent to 6 percent
of the nitrogen applied. It appears that the rate of nitrogen application may influence the quantity
of nitrate leaching from turfgrass sod, but this is most likely to be a problem with turf that has been
subjected to long term intensive fertilization rates.

     Because no significant crop is removed from a turfgrass sod unless the clippings are collected,
 there is little mechanical or cultural nitrogen loss. If fertilizer nitrogen is repeatedly applied at elevated
 rates (greater than 200 kg/ha/year) the soil-plant system may become "nitrogen saturated" and
 generate substantial nitrate leaching. To reduce the potential for groundwater contamination, turf
 managers would be well advised to maintain their grass with less than 150 kg/N/ha/year, to utilize
 slow-release organic formulations, and to carefully control supplemental irrigation.

                                       LITERATURE CITED
Aronson  LJ, A.J^Gold, and  R.J.  Hull. 1987. Cool-season turfgrass response to drought stress. Crop  Science
Aronson, L.J., A.J. Gold, RJ. Hull and J.L. Cisar. 1987. Evapotranspiration of cool-season turfgrass in the humid northeast
        Agron. J. 79:901-905.
Beard, J.B. 1973. Turfgrass: science and culture. Prentice-Hall, Englewood Cliffs, NJ.
Bredakis, E.J. and J.E. Steckel. 1963.  teachable nitrogen from soils incubated with turfgrass fertilizers. Agron J. 53:
Brown, K.W., J.C. Thomas, and R.L. Duble. 1982. Nitrogen source effect on nitrate and ammonium leaching runoff losses
        from greens. Agron. J. 72:947-950.
Brown, K.W., R.L. Duble and J.C. Thomas. 1977. Influence of management and season on fate of N applied to golf greens
        Agron. J. 69:667-671.
Cisar, J.L. 1986. Cool season turfgrass response to moderate fertility. Ph.D. diss. Univ. of Rl, Kingston.
Endleman, F.J., D.R. Kenney, J.T. Gilmour, and P.G. Saffigna. 1974. Nitrate and chloride movement in the plainfield loamy
        sand under intensive irrigation. J. Environ. Qual. 3:295-298.
Hays, J.T. and W.W. Haden. 1966. Soluble fraction of ureaforms nitrification leaching and burning properties. J. Ag. Food
        Chem 14:339-341.
Hesketh, E.S. 1986. The efficiency of nitrogen use by Kentucky bluegrass turf  as influenced by nitrogen rate, fertilizer
        ratio and nitrification inhibitors.  M.S. Thesis, Univ. of Rl, Kingston Rl, p. 88.
Huber, D.M.,  G.A. Murray, and J.M. Crane.  1969. Inhibition of nitrification as a deterrent to nitrogen loss. Soil Sci. Soc.
        Amer. Proc. 33:975-976.
Hughes, T.D.  1976. Nitrogen  release from isobutylidene diurea: soil pH and fertilizer size effects. Agron. J. 68:103-106.
Hull,  R.J., E.S. Hesketh, and A.J. Gold. 1987. Factors influencing  nitrate leaching from lawn turf to ground water.
        Completion Rept., Rhode Island Water Resources Center, Kingston, Rl 24 p.
Hull, R.J., E.S. Hesketh, and H. Liu.  1988. Can nitrification  inhibitors increase  nitrogen use efficiency  by turfgrasses?
        Agron. Abstracts, In press.
Morton, T.G., A.J. Gold and W.M. Sullivan. 1988. Influence of overwatering and fertilization on nitrogen losses from home
        lawns. J. Environ. Qual. 17:124-130.
Nelson, J. 1980. Summer and fall color retention of Kentucky bluegrass receiving varying amounts and timing of inorganic
        or inorganic-organic combinations of nitrogen. Can. J. Plant Sci. 69:1015-1021.
Owen, T.R. and D.Barraclough. 1983.  The leaching of nitrates from intensively fertilized grassland. Fert. Agric. 85:43-50.
Pochop, L.O., J. Borelli, J.R. Barnes, and P.K. O'Neill. 1978. Water requirements and application rates for lawns. Wyoming
        Water Res. Rsch Int., Wat. Res. Series No. 71.
Prasard, M. 1976. Nitrogen nutrition and yield of sugarcane as affected by N-Serve. Agron. J. 68:343-346.
Rieke, P.E. and B.G. Ellis. 1974. Effects of nitrogen fertilization on nitrate movement under turfgrass. p. 120-129. In:
        E.D.  Roberts (ed.) Proc. Int. Turf. Conf., Blacksburg, VA. 19-21 June 1973. ASA, Madison, Wl.
Ryther, J.A. and W.M. Dunstan. 1971. Nitrogen phosphorus and eutrophication in the coastal marine environment. Science
Snyder,  G.H., B.J. Augustin,  and J.M. Davidson. 1984. Moisture sensor-controlled irrigation for reducing N leaching in
        bermuda grass turf. Agron. J. 76:964-969.
Snyder,  G.H.,  E.G. Burt and J.M. Davidson. 1981. Nitrogen leaching on bermuda grass turf: Effect of nitrogen source and
        rates. Proceeding of 4th Intern. Turfgrass Conf. Guelph, Canada: 313-324.

Starr, J.L. and H.C. DeRoo. 1981. The fate of nitrogen fertilizer applied to turfgrass. Crop Science 21: 531-536.
Throssell, C.S., R.N. Carrow, and G.A. Milliken. 1987. Canopy temperature based irrigation indices for Kentucky bluegrass
        turf, crop sci. 27:126-131.

USEPA. 1976. Quality criteria for water. U.S. Gov. Print. Office, Washington, DC.
Waddington, D.V. and J.M. Duich. 1976. Evaluation of slow-release nitrogen fertilizers on Pennpar creeping bentgrass.
        Agron.J. 68:812-815.

Waddington, D.V., E.L. Moberg, J.M. Duich  and T.L. Watschke. 1976.  Long-term evaluation of slow-release nitrogen
        sources on turfgrass. Soil Sci. Soc. A. 40:593-597.

Waddington, D.V., T.R. Turner, and J.M. Duich.  1975. Response  of cool-season turfgrasses to liquid applications of
        fertilizer. Progress Rept. 350, Pennsylvania State Univ. Agric. Exp. Sts. Univ. Park, PA p. 31.

Warren, H.L., D.M. Huber, D.W. Nelson, and O.W. Mann. 1975. Stalk rot incidence and yield of corn as affected by
        inhibiting nitrification. Agron. J. 67:655-660.

Wesely, R.W., R.C. Shearman and E.J. Kinbacher. 1988. 'Park' Kentucky blue response to foliarly applied urea. Hort.
        Science 23:556-559.

Wilkinson, J.F. 1976. Effect of IBDU and UF rate, date  and frequency of application on Merion Kentucky bluegrass.
        Agron.J. 69:657-661.

                                   TABLE 1
Classification, burn potential, leaching potential, low temperature response and residual
effect of common turfgrass nitrogen sources.
Fertilizer   N content
Source            %
                                 Burn     Leaching    Low Temp    Residual
                               Potential   Potential    Response    Effect
Synthetic Inorganic
Calcium nitrate
Synthetic Organic
Urea solutions
Sulfur coated
Natural Organic









Very High
Very High





Very Low


Mod. High

Mod. Low
Mod. Low

Mod. Low



Very Low







Very Low









                              FIGURE 1
                      Turf grass Nitrogen Cycle
               ROOT UPTAKE


                                        GROUND WATER
                                                ROOT UPTAKE

                  SURFACE RUNOFF FROM TURF

                                    M. S. Welterlen
                           Grounds Maintenance Magazine
                                    P.O. Box 12901
                               Overland Park, KS 66212
                             formerly, Dept. of Agronomy
                                University of Maryland
                               College Park, MD 20742
                            C.M. Gross, J.S. Angle, R.L Hill
                               Department of Agronomy
                                University of Maryland
                             College Park, Maryland 20742
    Nonpoint source pollution of waterways has received considerable attention in recent years
as a result of a decline in water quality of these waterways and subsequent declines in desired
resources derived from them. In assessing the impact of nonpoint source pollution of waterways the
quality and quantity of surface and ground water emanating from various aspects of the watershed
must be critically evaluated.

    Sensitive areas such as the Chesapeake Bay, which is one of the most productive estuaries
in  the world, are particularly vulnerable  to impacts by actions  throughout their watersheds.
Watersheds such as the Chesapeake Bay are comprised of various land uses such as  forestation,
urbanization and crop production. Surface characteristics as well as fertilizer and pesticide loading
on these areas have been shown to affect the quality and quantity of water emanating  from the
watershed. Consequently, land use has been more critically reviewed in sensitive areas  in recent

    Urbanization with associated suburbanization has increased  dramatically in the Northeast
United States, Urbanization results in an increase in impervious surfaces which accelerate surface
runoff from watersheds. In addition,  an increase  in the amount of turf acreage has also  occurred
with urbanization as residential  lawns,  parks,   highway roadsides  and other turf  areas  are
established. Surveys conducted  by the Maryland Department of Agriculture (1987) indicated an
increase in Maryland turf acreage from 346,871 in 1979 to 614,024 in 1986. The increase in turf
acreage has prompted public concern as to ecological impacts of turf management, since turf makes
up a growing proportion of the watershed in urban areas.

    This chapter will discuss research relating to the effects of turf on  surface water movement. A
discussion of the effects of turf on ground water quality is included elsewhere in this text.


    Turf is composed of many closely spaced individual plants that form a closed canopy over the
soil surface. Turf density, leaf texture and  turf canopy height are primary physical factors relating
to dissipation of impact energy of rain droplets and resistance to surface movement of water over
turf. Approximately 80 percent of  the extensive fibrous root system of turfgrass is located in the


upper 5 cm of soil. The protective nature of both the turf canopy and the root system are responsible
for the soil stabilizing effects of turf.

     Turf  density varies  depending on inherent  characteristics, environmental  conditions and
management.  Creeping bentgrass (Agrostis  palustris Huds.) which is  used as an  intensively
managed turf, may exhibit density as high as 1,700 plants dm-2, whereas Kentucky bluegrass (Poa
pratensis L.) density may be as low as 100 plants dm-2 and tall fescue (Festuca arundinacea Shreb.)
less than  100 plants dm-2 (Beard, 1973). Cultural factors  that  increase shoot density include close
mowing, adequate moisture and nitrogen fertility (Roberts, 1965).

     Leaf texture refers to the width of turfgrass leaf blades and varies among turfgrass species
and varieties (Table 1) as well as management and seeding rate (Table 2). In order to maintain turf
uniformity, seeding mixtures are formulated with turfgrasses of compatible texture.

     Optimum canopy height of  maintained  turf depends on the  species  and intended use.
Residential lawns are typically maintained at heights ranging  from 2 to 8 cm. Highway roadsides
are  generally maintained at 8 to  13 cm, and golf course fairways  are mowed at 1.3 to 3.8 cm
depending on the species.

     Research conducted on the effects of grasses, in general, and turfgrass, in particular, on
surface runoff has been documented, and more research is currently underway. Numerous studies
have shown that grass buffer strips are quite effective in reducing runoff and the sediment and
nutrients carried with it (Gross et al., 1987; Hayes et al.,  1978; Tollner, et al.,1977; U.S. E.P.A.,
1983a and 1983b; and Young et al., 1980). Most of the work conducted over the past 25 years
pertaining to the pesticide content of surface waters draining from agricultural fields has  been
reviewed by Pionke and Chesters (1973) and Wauchope (1978). In cases where water quality has
declined due to nutrient and pesticide movement in water or eroded sediment, the  use of grassed
buffer strips between treated fields and the receiving bodies of water have significantly reduced t^e
problem. The Cooperative Extension Service in the Chesapeake Bay area currently recommends
the planting of grass filter strips as well as natural vegetation filter areas for reducing runoff from
field crops (Extension Services of the Chesapeake Basin, 1985). Doyle, et al. (1977) evaluated the
effectiveness of forest and grass buffer strips in improving water quality of manure  polluted runoff.
The authors determined that both forest and grass buffer strips  of approximately  4 meters  were
found to be effective in reducing levels of fecal bacteria from manure treated plots. Total soluble
NH4-N, NO3-N, P and K levels were also reduced by the buffers.

     Studies relating to surface runoff from turf are currently underway at the University of Maryland
(Gross et al, 1988, unpublished data). Another study conducted on a Sassafras sandy loam with a
slope of 8% at the University of Maryland (Gross et al, 1988, unpublished data), evaluated the effects
of rainfall intensity and turfgrass seeding rate (density) on runoff initiation time,  runoff rate and
sediment loss. Three rainfall intensities (3.0 inches per hour,  frequency  of once every two years;
3.7 inches per hour, frequency of once in every 5 years and 4.7 inches per hour, frequency of once
in every 20 years) were imposed with a rainfall simulator. Under a rainfall intensity of 4.7 inches per
hour, runoff rate was reduced by 50% with tall fescue, seeded at 10 Ib. per 1,000  sq. ft. one year
prior to testing, in comparison to bare ground (Fig. 1). Runoff initiation time was positively correlated
with rainfall intensity and seeding rate (Fig. 2). Under a rainfall  intensity of 3.7 inches per  hour,
sediment loss was reduced from 1.1 g m-2 min-1 (bare ground) to  0.1 g m-2 min-1 (on turf originally
seeded at 10 Ib. seed per 1,000 ft.-2) (Fig. 3). Researchers in Pennsylvania (Harrison et al, 1988)

showed that only 5% of applied water (6 in./hr) ran off slopes with Kentucky bluegrass sod, whereas
approximately 20%  of applied water ran off slopes established by seeding.  Consequently,  by
sodding critically-sloped areas during initial stages of construction, runoff can be further reduced.
These studies indicate general trends in the effects of turf and rainfall intensity on surface water
and sediment movement; however, it is important to note that specific values may vary depending
on soil type, terrain, turfgrass species, turf quality and naturally occurring rainfall in the area.

     Research conducted by the University of Maryland (Gross, et. al.  1987) at the Chesapeake
Bay Foundation Research Farm in Upper  Marlboro, Maryland showed that surface water runoff
volume, sediment loss, total N movement and phosphate movement were dramatically lower in turf
in comparison to conventional  tobacco (Table 3) under natural  rainfall. Under simulated rainfall
intensities, turf was also shown to be superior to corn in terms of stabilizing soil (Table 4). With an
intense rainfall occurrence of 4.7 inches per hour, turf was 133 times more effective in stabilizing
soil in comparison to corn.  These studies also indicated that annual runoff volume from tall fescue
was five times less than from conventionally planted tobacco. Sediment loss was 4,730  kg ha-1
from tobacco versus 5.8 kg ha-1  from turf. Total  N was 11.7 kg ha-1 from tobacco versus 0.11 kg
ha-1 from turf and ortho-P loss was 0.42 kg ha-1  from tobacco versus 0.03 kg ha-1 from turf.

     The ability to project amounts of pesticides  in surface waters emanating from a  turf site
depends on  several factors including: amounts and rates  of degradation of specific pesticides  to
be applied, pest pressure, rainfall intensity  at the site, topography and landscape design. Since
pesticides vary in  their chemical  characteristics,  they differ in their rate  and mode of degradation
(by microbial, photochemical and hydrolytic  means), soil adsorptive tendencies, and volatilization.
A thorough  review  of these characteristics is  presented in several sources  (Farm Chemicals
Handbook, 1988; Herbicide Handbook, 1983; Saltzman and Yaron, 1986).

     The stabilizing effects of turf must not be overlooked in developing land use strategies. In
 developing such strategies, turf is often equated with impervious surfaces, which is far from the
 conclusions that have been documented by research. Before alternative ground covers are adopted
 for sensitive sites, we must first consider the environmentally beneficial aspects of turf and determine
 whether the alternative ground cover will provide improved results.

                                       LITERATURE CITED
 Beard, J. B., 1973. Turf grass science and culture. Prentice-Hall Publishing Co. Englewood Cliffs, NJ.
 Doyle, R. C., G. C. Stanton, and D. C. Vtolf. 1977. Effectiveness of forest and grass buffer strips in improving the water
        quality of manure polluted runoff. Proceedings of the 1977 Winter Meeting of the American Society of Agricultural.
        Paper No. 77-2501.
 Extension Services of the Chesapeake Basin. 1985. Best management practices for nutrient uses in the Chesapeake
        basin. Bulletin 308 College of Agriculture, University of Maryland, College Park, MD.
 Farm Chemicals Handbook. 1988. Meister Publishing Co. Willoughby, Ohio.
 Harrison, S., T. L  Watschke and G. Hamilton. 1988. Turfgrass runoff update.  ASPA News, American Sod Producers
 Gross, C. M.,  J. S. Angle, R. L. Hill and M.  S. Welterlen. 1987.  Natural and  simulated runoff from turfgrass. Agron.
        Abstracts. 79:135.
 Hayes, J. C., B. J. Barfield and R. I. Barnhisel. 1978. Rltration of sediment by simulated vegetation II. Unsteady flow with
        non-homogeneous sediment. Transactions of the ASAE: 21 (10): 1063-1067.
 Maryland Department of Agriculture. 1987. Maryland turfgrass survey,  1987. Maryland Department  of Agriculture and
        Maryland Turfgrass Council. Annapolis, Maryland.
 Pionke, H. B. and G. Chesters. 1973. Pesticide-sediment water interactions. J. Environ. Qual. 2:23-45.
 Roberts, E. C. 1965. A new measurement of turfgrass response and vigor. The Golf Course Reporter. 33:10-20.
 Saltzman, S. and B. Yaron. 1986. Pesticides in soils. Von Nostrand Reinhold Co., New York.
 Tollner, E. W., B. J. Barfield, C. Vachirakornwatana and C. T.  Haan. 1977. Sediment deposition  patterns in simulated
        grass filters. Transections of the  ASAE 20 (4): 940-944.
 U.S. Environmental Protection Agency. 1983. Reducing runoff pollution using vegetated borderland for manure application
        sites. USEPA Rep. 600/52-83-022. U.S. Government Printing Office, Washington, D.C.
 U.S.  Environmental Protection Agency.  1983. Swine  manure and lagoon  effluent applied  to fescue.  USEPA Rep.
        600/S2-83-078. U.S. Government Printing Office, Washington, D.C.
 Wauchope, R. D. 1978. The pesticide content of surface water draining from agricultural fields:  A review. J. Environ.
        Qual. 7:459-472.
 Weed Science Society Of America. 1983.  Herbicide Handbook.  W.S.S.A.
 Young, R. A., T. Huntrods and W. Anderson. 1980. Effectiveness of vegetated buffer strips  in controlling pollution from
        feedlot runoff. J. Environ. Qual. 9 (3): 483-487.

                                      TABLE 1
    Comparison of leaf texture of turfgrasses mowed at 3.8 cm (Adapted from Beard, 1973)
Textural Category

Very Fine



 Leaf Width

 Less Than 1



 Very Coarse
Greater than 4
Turfgrass Species
Creeping red fescue
Velvet bentgrass
'Emerald1 zoysiagrass
Rough bluegrass
Kentucky bluegrass
'Meyer' zoysiagrass
Annual bluegrass
Annual ryegrass
Tall fescue
St. Augustinegrass

                                       TABLE 2
     Effects of seeding rate on leaf texture of 9 month old tall fescue mowed at 6 cm in Silver Spring,
 Maryland (Welterlen, 1984, unpublished data).
                      Seeding Rate           Width of Second Leaf
                      Ib./1,000ft2             -mm-

                      2                       5.7 a*
                      4                       5.5 ab
                      6                       5.3 be
                      8                       5.3 be
                      10                      5.3 be
                      12                      5.2 cd
                      14                      5.1 d
                      16                      5.0 d
    Means followed by the same letter are not significantly different at the 0.05 level according to
    Bayes Least Significant Difference.

                                   TABLE 3
    Comparison of tobacco versus tall fescue turf in surface movement of water, sediment and
fertilizer (Gross, et al., 1987).

Crop               Runoff Volume   Sediment     Total-N        P04-P

                     Lx103ha'1       kg ha-1      kghff1        kghr1

Conventional         334.0          4730        11.7          0.42
Tall Fescue              74.5           5.8         0.11          0.03

                                       TABLE 4

     Sediment loss from com versus tall fescue (Gross, et al. 1987).

                                                   Sediment Loss
                Rain Intensity          fall Fescue Turf              Corn

                   In. hr1                       —-  gm nv2 mln-1 —

                     4.7                    0.18                    24.0

                     3.7                    0.12                    14.1

                     3.0                    0.08                    10.0
 *   Rainfall was imposed with a rainfall simulation device. Rainfall intensities of 4.7, 3.7, and 3.0
 inches per hour correspond to 30 minute rainfall events which occur every 20, 5 and 2 years,

                    AND A MID-SOUTH REGION
                                   Jim Schaefer
                                   Larry Larson
                       Research and Development Department
                              Soil technologies Corp.
                                  51 West Adams
                                 Fairfleld,  IA 52556

    TURFtech is a commercial microbial product composed of chlamydomonas, chlorella and
cyanobacteria. The purpose of the product is to provide a seeding of viable dormant microorganisms
at the rate of 18.2 x 109 cells acre-1, per application, to a turf's soil surface, thereby establishing
an artificial advantage for these selected strains, and culturing the organisms for three to five
weeks. The artificially induced large population of microbes then act as sources for the production
of biopolymers or microbial polysaccharides, an organic soil-aggregating agent. These microorganisms
grow on  soils and secrete quantities of polysaccharides (Kroen, 1984). The addition of microbial
polysaccharides to soil generally improves aggregate development and stability (Lynch and Bragg,
1985). Lewin (1977)  and  Melting  (1986) collected empirical  evidence suggesting these same
microbes as efficacious agents for beneficial alteration of soil structure.

    Considerable evidence is published which  suggest  that soil compaction of various forms
seldom favors the economics of turf production and generally works against it (Gill, 1971). Soil
structural degradation has been blamed by various researchers for plant growth reductions (Baver
and Farnsworth, 1941; Lawton, 1945; Quastel,  1952; Gill and Miller, 1956; Hagin, 1952; Voorhees
et al, 1975). This paper will report field results where bearing ring cone penetrometer readings were
collected at sites which were seeded with the TURFtech product.

                        MATERIALS AND METHODS:

    Two experimental regions were established for test sites for 1987 and one region for 1986.
The regions were distinguished as having similar soil origins and climactic conditions. The regions
were called Southeast Iowa (north of Highway 34, and south of I-80 and east of Knoxville) and the
Mid-South (Eastern Arkansas and  the northwest 1/4 of Mississippi). Each represented a single
experimental area. Each test site belonged to a cooperating TURFtech customer. The operators
purchased and applied the TURFtech product, which consists of single cells uniformly dispersed
in a dry,  suspendable, clay based powder. This material was mixed with water and applied with
conventional spray equipment at the rate of 4 ounces with between 30 to 60 U.S. gallons of water
per acre.  Seeding, or application, was done in the spring. In each case, for 1986 in Southeast Iowa
and for the Mid-South in 1987, the treated areas were receiving their first seeding with TURFtech .
Southeast Iowa treated areas were treated again in 1987. A seeded and non-seeded area (or plots)


were located side by side at each site. The experimental measurement area was within this area.
Each test or measurement area was 45m2 with one half of the area the seeded area and the other
half the non-seeded area. Each measurement area was selected for uniformity of soil type, slope,
drainage pattern, and cultural history.

     For compaction  data collection a Soiltest bearing ring cone penetrometer was used. The cone
had a cross sectional area of 2.54 cm2 and had a 30 degree angle. Twenty subsample data sites
were randomly selected, for each the seeded and non-seeded areas  for probing.  Each of the 80
Southeast Iowa and  38 Mid-South sites were probed one time, approximately 6 weeks after the
TURFtech seeding. The twenty subsample measurements were integrated to produce a mean for
each  the seeded and  non-seeded  areas,  and  all  measurements  were  adjusted to  U.S.
pounds/inch2 for each replicate. Measurements were taken at the two and four inch depths in 1986
and 1987. A one inch soil core to  the four inch depth was taken  at every fourth to tenth subsample
data site for each replicate. Gravimetric moistures were analyzed on each soil sample. The 2 to 5
gravimetric subsample moistures for  each the seeded and non-seeded areas were integrated
producing a percent moisture mean for each the treated and non-treated area of the replicate.

     Each measurement area,  containing  a treated and non-treated plot, represented a replicate
or block. Thus, the  statistical design was  that of a randomized complete block, with  each
measurement  area or test site treated as a replication.

     The bearing ring cone penetrometer measurements for all test sites are presented in Table 1.
 For all test sites the TURFtech seeded area had significantly less penetrometer resistance to both
 the two and four inch depths. The soil water content difference between the seeded and non-seeded
 areas was not significant.

     Certain soil organisms produce polysaccharides that have a mucilaginous nature and may
cement mineral particles together. Rennie et al. (1954) found that the addition of only 0.02g of an
extracted and purified soil polysaccharide material to 100g  of soil increased the water-stable
aggregates > 0.1mm in diameter from 44g to 60g. Chesters et al. (1957) on analysis of a large
number of soils, indicated that per unit mass, the polysaccharide fraction was more effective in
stabilizing the mineral particles into structural units than was the non-polysaccharide portion of the
soil organic matter.

     In experimental work, it is frequently desirable to evaluate soil structure issues because the
most suitable management practices may depend on the  extent to which structure affects the
growth of plants. With the advent of synthetic, organic soil-aggregating agents, with only small direct
effects on the microbiological population and nutrient status  of soils, structural  effects  on plant
performance could be measured.  It has  been  observed that in some cases the improvement of
structure through field application of a synthetic organic soil-aggregating agent did not improve plant
growth (Clement,  1961) and in other examples a definite improvement in plant growth could be
attributed to structural improvements associated with the addition of the aggregating agent (Boekel,
1963). It  is generally agreed that improved soil structure is beneficial to soil as a medium for plant


    Within one season, with four TURFtech seedings, the measurement of force required to
displace or shear soil with a bearing ring cone penetrometer was significantly reduced at both the
two and four inch depths, (Table 1). The measurement of greater comparative reductions at the two
inch depths versus the four inch depths, is probably due to the majority of the microbial produced,
organic, soil-aggregating agent being tied up with the soil  mineralogy in the upper zone  of the
measurement depth. Each test site used a different type and design of spray equipment to  seed
soils with the product. The total number of sites should have minimized any bias in the data  due to
inconsistence in the equipment calibration. An inconsistent number of soil moisture readings per
site was calculated. However, the total number of moisture evaluations was high and the moisture
bias in the penetrometer calculations was statistically insignificant. These measurements appear
to produce a correlation between the seeding of surface soils with a microbial product, a presumed
biological source for an organic, soil aggregating agent, and decreases in surface soil compaction.

     It is at least suggested by this work that a soil response may be associated with the TURFtech
seeding  of certain  surface soils,  possibly more  so with those identified in  need of structural

     I wish to thank Rick Cruse, Ph.D. Department of Agronomy, Iowa State University, Ames, Iowa,
 for his guidance with regard to the experimental design in this report.

                                     TABLE 1
     Bearing ring cone penetrometer measurements at two and four inch depths.
Depth Replicates
inches (a) Region (b)
lbs./inch2 % Moisture Ibs./inch2
Seeded Seeded Non-
Mean Mean Seeded
40.63 (c)
33.57 (c)
47.96 (c)
95.29 (c) 15.7(d)
94.23 (c)
1 56.98 (c) 12.08(d)
                                                               % Moisture
(a)  Depth in inches per year.

(b)  Each replicate treated as a randomized complete block.
    SEIA = Southeast Iowa and MS = Mid-South.

(c)  Significant at 1% level.

(d) Insignificant at 5% level.

Barber, Stanley A. 1959. The influence of alfalfa, bromegrass, and corn on soil aggregation and crop yield Soil Sci  Soc
        Am. Proc. 23:258-259.
Baver, L.D. and R.B. Farnsworth. 1941. Soil structure effects on growth of sugar beets. Soil Sci. Soc. Amer. Proc. 5:45-48
Boekel, P. 1963. Soil structure and plant growth. Netherlands J. Agr. Sci. 11:120-127.
Chesters, G., O.J. Ahoe, and O.N. Allen. 1957. Soil aggregation in relation to various soil constituents. Soil Sci Soc Am
        Proc. 21:272-277.
Clement, C.R. 1961. Benefit of leys-structural improvement or nitrogen reserves. J. British Grassland Soc. 16:194-200.
Gill, W.R. 1971. Economic assessment of soil compaction. In: Compaction of Agricultural soils. K.K. Barnes, W.M. Carlton,
        H.M. Taylor, R.I. Throckmorton, and G.E. Vanden Berg (eds.) Am. Soc. Agri. Eng. St. Joseph, Ml.
Gill, W.R. and R.D. Miller.  1956. A method of study of the influence of mechanical impedance and aeration on the growth
        of seedling roots. Soil Sci. Soc. Am. Proc. 20:154-157.
Hagin, J. 1952. Influence of soil aggregation or plant growth. Soil Sci. 74:471-478.
Kroen, W.K. 1984. Growth and polysaccharide production by the green alga Chlamydomonas mexicana (Chlorophyccae)
        on soil. J. Phycol. 20:616-618
Lawton, K. 1945. The influence of soil aeration on the growth  and absorption of nutrients by corn plants. Soil Sci.  Soc.
        Am. Proc. 10:263-268.
Lewin, R.A. 1977. The use of algae as soil conditioners." Centres. Invest. Baja Calif., Scripps Inst. Oceanogr. 3:33-35.
Lynch, J.M., and E. Bragg. 1985. Microorganisms and soil aggregate stability. Adv. Soil Sci. 2:133-171.
Melting, B. 1986. Dynamics of wet and dry aggregate stability  from a three-year microalgal soil conditioning experiment
        in the field. Soil Sci. 143:139-143.
Quastel, J.H. 1952. Soil Conditioners. Annual Rev. Plant Physiol. 5:75-92
 Rennie, D.A., E. Truog, and O.N. Allen. 1954. Soil aggregation as influenced by microbial gums, level of fertility and kind
        of crop. Soil Sci. Soc. Amer. Proc. 18:399-403.
 Vborhees, W.B., D.A. Farrell, and WE. Larson. 1975. Soil strength and aeration effects on root elongation. Soil Sci. Soc.
        Am. Proc. 39:948-953.


   State of the Art Research on
    Control of Turfgrass Pests
Through Use of Naturally Occurring
        Endophytic Fungi




              Malcolm R. Slegel, Douglas L. Dahlman and Lowell P. Bush
                          Departments of Plant Pathology,
                            Entomology and Agronomy,
                               University of Kentucky
                             Lexington, KY 40546-0091
    The infection of grasses by consistently symptomless nonsporulating endophytic fungi has
been known for many years, but only recently attracted attention  because of the  economic
importance associated with animal toxicoses and resistance to insect predation. Since the initial
work of Bacon et aL (2) in 1977 and Fletcher and Harvey (11) in 1981, which established the
respective associations of  animal toxicosis with endophyte-infected tall fescue and perennial
ryegrass, researchers have come to further understand the relationship between fungal endophytes
and their host grasses. Recent studies have addressed the origin and incidence of endophyte-
infected grasses, modes of dissemination of the fungi, identification of the chemicals responsible
for mammalian and  insect toxicoses,  and the significance  of ecological and physiological
relationships between grass hosts and endophytes.

    In this chapter, we will  present a general review dealing with the biology, ecology and
physiology of the host-fungus interaction as well as some specific information on the nature of the
biological control of insects and diseases by endophyte-infected grasses. The aspect of biological
control of pests deals with the potential use of infected turfgrasses in the urban environment.
Introduction of these grasses could result in reduction of  pesticide usage and  the undesirable
ecological side effects of chemicals  used  on turf. However, the successful use of endophyte-
improved turfgrass cultivars depends on a number of factors which are related to the nature of the
host-fungus interaction.
    In addition to the information presented here, there are other chapters in this book by Bacon
(Chapter 17) and Funk et aL (Chapter 18) that detail further the production of specific toxins in
endophyte-infected grasses and  endophyte-enhanced performance of turfgrass, respectively.
Because there are a number of recent reviews on fungal endophytes (1,3,8,26,36,37), we will only
reference those statements which represent new information or those which need further emphasis.


    The term endophyte, in regard to infection of grasses, was defined previously by Siegel el aL
(37) as a fungus which is contained or growing (entirely) within the substrate plant, spending aH or
nearly all of its life cycle in the host. Almost all of the  grass  endophytes are grouped or related to
fungi  in the tribe Balansiae (genera; AtkiDSoneila, Balansia,  Blansiopsis, Myriogenospora and


Epichloe) of the family Clavicipitaceae. They are common biotrophic inhabitants of grasses, which
have a C-3 type photosynthetic pathway, and sedges. Other non-related endophytes (Phialophora-
like and Gliocladium-like spp.) have been described as well (17).
     A generalized life cycle of the grass endophytes is illustrated in Fig. 1. In relation to this life
cycle, it is germane to emphasize those endophytes which remain symptomless versus those which
produce  sporulating fructifications and prevent flowering. The mycelia of both symptomless and
symptom-producing endophytes grow intercellularly (10,13,35), infecting meristems, leaf sheaths,
and sometimes blades. In addition, the symptomless endophytes infect seed, growing in association
with the aleurone layer and seed embryo. Unless symptoms are produced, the plant appears to be
undamaged and the fungus becomes incorporated into the plant's reproductive system. The only
known means of dissemination of symptomless endophytes is through maternal transmission of
infected seed (solid arrow, Fig. 1).
     It is the group of systemic seedborne fungi for which no sexual state has been found  (often
called symptomless parasites), as well as related fungi in the genus Epichloe that currently offer
new approaches to biological control of pests of turfgrass. Epichloe typhina is a common pathogen
of  grasses producing  the striking symptom  of  mycelium  surrounding  the emerging flower
inflorescence, with  the subsequent prevention of flowering and seed production (called choke
disease). This fungus is found on important grass genera, in primarily the Poaceae (e.g., Agrostis,
Bromus. Dactylis. Festuca. Holcus. Hordeum. Lolium and Poa). There has been  debate recently
about the  taxonomy of the anamorphic state (asexual) of E typhina. Originally classified as
Sphacelia typhina. it now has been reclassified by Morgan-Jones and Gams (23) and confirmed
by White  and Morgan-Jones (49)  as  Acremonium  typhinum.  Other important symptomless,
seedborne endophytes found in grasses for which there are no known teleomorphic states (sexual)
are now also classified in the same genus Acremonium sec. Albo-lanosa. While this classification
implies  morphological relatedness,  Johnson  et a! (15) have also demonstrated  serological
relatedness among some Acremonium spp. and EL typhina isolated from different grasses. The list
of named Acremonium endophytes is shown in Table 1. It should be pointed out that by staining the
mycelium in vegetative tissue and in seed, numerous endophytes have been found in grasses of
the Poaceae but remain as yet unnamed (19,29,41,46).
     The emergence of A^ typhinum at flowering depends on the biology of the  grass-fungus
association, which will be discussed shortly. When choke symptoms occur, conidia of >V typhinum
are produced on the stroma (broken arrow, Fig. 1). Whether the sexual ascomycetous state of E
typhina occurs depends on simple bipolar heterothalism (two mating types present) and insect
transmission of conidia, which act as spermatia (43). While it has been suggested that species of
the Balansiae producing  external spores infect healthy plants via the stigma and style to the  ovule
(9), it is also possible that spores infect tillering buds of grasses as well. There is some uncertainty
as to the role of ascospores in the life cycle of these organisms as well as to the mode of infection.
     It has  been  known, since the work of Sampson (30), that EL typhina may remain symptomless
for long periods and be seed disseminated in certain host grasses (12,29). Consequently, Siegel et
ai (37) and Bacon and Siegel (3) consider E, typhina to  exist as different biotypes in various host
grasses. The existence of fungal biotypes suggests that  there is a continuum within the symbiotic
association  as it relates to the compatibility of the partners (22,38). Some biotypes  enter into
agonistic (parasitic-pathogenic)  interactions whereas others,  like the  symptomless Acremonium
spp. infecting Festucoideae grasses, enter into mutualistic (beneficial) relationships.
     White  (42) has differentiated into three types the associations between E typhina and related
Acremonium endophytes,  and  their  grass hosts (Table 2).  The biology  and  ecology of the
associations are  important in understanding the distribution of infected plants in the population and

dissemination  of the endophytes.  In type 1 associations, infected plants  produce stromata  fan
external  mat  of mycelium bearing fructifications)  on nearly 100% of the flowering panicles
Populations of plants in this association tend to remain small, spreading primarily as the grass clone
spreads vegetatively. All of the plants in this clonal population are infected. Type 2  like  type 3
associations, have  been found  only  in the Festuciodeae. The differences  between these two
associations are relatively minor and involve the identity of the fungus and the distinction between
the low level (0 vs.  1-10%) of flowering panicles showing stromata. The spread of endophytes in
type 2 and 3 associations is  primarily by seed dissemination, however, ascospores may also be
important in the former association.

     The percent of the population infected in type 2 and 3 associations may depend on whether
the grass is present in recent  or older cultivations or is from native species. One would expect high
levels of infection in the population of wild grass species as it has been  hypothesized that the
endophytes co-evolved with  their hosts (37,42). High percentages of infected plants  have been
reported  to occur in various Lolium and Festuca spp. growing in the wild in the U.S. and Europe
(19,34,42). Populations of  older cultivated grass species appear to be highly infected whereas
others from recently introduced cultivars or new cultivation have low levels of infection. For example,
58% of the tall fescue plants, grown on 14 million hectares, in the U.S. have been reported to be
infected with A. coenophialum (31); nearly 100% of the perennial ryegrass plants, grown on 6  million
hectares, in New Zealand are infected with ^ Mi (19,37).  Seed of perennial  ryegrass (19) and fine
fescues (29) collected from old pastures and turf in Europe also had high levels of infection.

     It is now clear that the seedborne and symptomless nature of the endophytes of type 2 and 3
associations has unintentionally resulted in their worldwide distribution along  with their cultivated
hosts. The reasons for the differences in levels of infection of cultivated grasses (old vs. new cultivars
or plantings) may have more to do with the commercial methods of handling  of seed than  with a
failure of the grass to remain infected.

     Seed-borne endophytes  survive for indefinite periods at low temperatures (0-5C), but generally
lose their viability in much shorter storage periods (1-2 yr) at 20-30C and high seed moisture levels
(40). Grass seed may be stored in the U.S. at ambient temperature for up to 18 months before it is
sold; consequently, seed lots can contain infected seed with different levels of endophyte viability
that result in reduced numbers of infected plants.

     Symptomless and seed disseminated Acremonium  spp.  and E typhina (type 2 and  3
 associations) can be considered as obligate biotrophs (20). That is, they cannot exist outside the
 host (except in laboratory culture) and additionally are not known to be capable of re-infecting, by
 natural means  susceptible grasses. As discussed earlier,  these endophytes are also  mutualistic
 symbionts, whereas EL typhina of type 1 associations and other specific endophyte species in the
 tribe Balansia are agonistic (parasitic) symbionts producing disease. The grass endophytes that are
 mutualistic symbionts receive benefit from the association with their hosts in the form of long term
 protection and enhanced survival and dissemination (via seed). These endophytes are of great
 interest because of the benefits they impart to the hosts. They cause or induce  in many instances
 improved growth and persistence of the host plants, tolerance to  herbivore feeding (animal and
 insect) and possible disease resistance. As will  be discussed  later, these endophytes can be
 manipulated for the production of improved turf-grass cultivars.

Improved plant growth and persistence

     Acremonium endophytes confer improved growth performance to some infected cultivars and
clones of perennial ryegrass and tall fescue. Plants of an infected perennial ryegrass clone had
more dry matter, total leaf area, tiller number and growth of roots than plants of the non-infected
clone (18) as well  as improved seed set, germination and seedling growth (7). While it has been
suggested that growth and survival are enhanced when field-grown infected tall fescue plants were
grazed (27), experiments in Kentucky with Kenhy tall fescue showed no significant differences in
plant growth and seed production between infested and non-infested mowed plots (34). However,
in greenhouse  tests, Bush  et aL (6) have shown that infected tall fescue plants performed better
(greater number of tillers, daily photosynthesis and net carbon fixed, and water use efficiency) than
non-infected plants. Belesky ei aL (5) have also reported greater tiller production and net growth in
some tall fescue clones grown under controlled conditions. However, in these experiments, net
photosynthesis rate  was lower while stomatal resistance tended to  be  greater in infected than
non-infected plants. These data support the hypothesis that infected cultivated grasses would have
an adaptive growth  advantage  over non-infected plants in environments  with abiotic stresses
(deficient water and nutrients, high temperature and competition with weed species).

     The reason for possible  changes in growth patterns of  endophyte-infected plants remains
obscure, although  it  has been suggested that endophytes localized in stem base and sheaths of
plants utilize reserve photosynthate (i.e., fructosans) (5). This utilization may impart source-sink
dynamics, altering the production and partitioning of photosynthate and, hence, growth in infected
plants. In addition, members  of the Claviciptaceae may produce auxins  or other plant  growth
regulators, or they may alter the hormone metabolism of their host. These are distinct possibilities
when one  considers that symptoms of  infection by E, typhina  and other members^of the tribe
Balansia include not only the inhibition  of flowers and seed, but also  enhanced plant  growth,
dwarfism or deformation of the flag leaf (1,8,9). Auxin-like indole compounds  have  been isolated in
vitro from cultures of  Claviceps pupurea and Balansia epichloe (25). The production of these indole
compounds may reflect an alteration of nitrogen metabolism and assimilation in the infected plant

Insect resistance

     One of the most striking effects produced by endophyte-infected grasses is resistance to insect
attack. This subject has been  extensively reviewed and will be discussed in detail by Funk et aL
(Chapter 18). An up-to-date list of species of insects reported to be affected by endophyte-infected
Festuca and Lolium species of grasses has been presented elsewhere (37 -see Table 1). In addition,
Pedersen et  aL (24) reported that there were lower populations of the spiral (Helicotylenchus
dihystera) and  stubby root  (Paratrichodorus christiei) nematodes in pots containing infected tall
fescue than in those containing non-infected plants.

     Acremonium and E^ typhina-infected grasses produce an array of chemicals that have a wide
range of biological activity. The chemistry and synthesis of these chemicals will be discussed by
Bacon (Chapter 17). Table 3 summarizes the current information  available concerning these active
chemicals. Of notable interest is peramine, an insecticidal compound originally recovered from /L
join-infected perennial ryegrass. This compound has also been found in many grasses infected with
A, coenophialum or E typhina (33). However, not all biotypes of E. typhina produce peramine, as
the compound was not recovered from the naturally infected cultivar Ensylva (Festuca rubra rubra)
or from Dawson (R rubra litoralis) artificially infected (via seedling wounding) with an JB typhina


isolate from an unidentified cultivar of R rubra grown in New Zealand (Siegel el aL unpublished
data).  Ergot alkaloids  originally found in A, coenophialum-infected  tall fescue have  also been
recovered from various E typNna-infected grasses (Bacon and Siegel, unpublished data) as well
as perennial ryegrass infected with A, lolii (28).

     The number and  quantity  of compounds found in endophyte-infected grasses may play an
important role  in determining  the spectrum of insecticidal activity as well as affect the potential for
the development of  insect resistance. Of the types of compounds listed in Table 3,  only loline
alkaloids are found in  high concentrations in the plant. The reputation for a high level of insect
resistance by infected  tall fescue may be  based, in part, on the concentration of loline  as well as
the presence of the  other toxic chemicals. On the other hand,  the compounds found in infected
perennial ryegrass are present at ca.  250 fold  less than the loline alkaloids but still exert a
considerable spectrum of activity (37). The ability of certain fungal symbionts (e.g.. A. coenophialum
and A.ipJii) to produce at least three biologically active compounds likely contributes  to an improved
spectrum of activity.  If one hypothesizes that insects would become resistant to these compounds
by different mechanisms, then potential for the development of resistance by the insect is  negligible.
From these aspects of the synthesis of insecticidal compounds in endophyte-infected grasses one
might speculate that the level of the chemical may be less important than the number of  chemicals
produced by the host-fungus  association.

     While the topic of this chapter involves the nature of endophyte-infected grasses, endophytes
from tall fescue and perennial  ryegrass used in pasture have been  removed to improve animal
performance.  These endophyte-free cultivars do not contain any of  the  biologically active
compounds found in  infected  grasses.  However, because  the fitness of the partners in the
grass-fungus association  involves mutualism, some  questions  have  been raised  about whether
these endophyte-free cultivars would be able to survive over long periods of cultivation  (32,37). It
is quite clear that removing the  endophyte from perennial ryegrass in New Zealand resulted in loss
of stands by predation of the Argentine stem  weevil and animal overgrazing. Whether attack by
insects, poorly managed grazing practices, reduced plant vigor and survival during periods of abiotic
stresses will also cause loss of  recently established endophyte-free tall fescue pastures in the U.S.
is currently unknown. However, small plots of Ky 31 and other tall fescue cultivars  containing low
levels of infected plants have  existed in the transition zone of the  southeastern U.S. for many years

     We have  devised laboratory assays to test for activity of  some of the chemicals produced in
infected plants. Figure 2 A,B illustrate one such assay system (14). The plastic cup contains a piece
of dental cotton (holds 300 ml of water), one sunflower seed and five Oncopeltus fasciatus (large
milkweed bug)  nymphs (1-12 days old).  Test chemicals in water or water alone are applied to the
cotton and the nymphs are allowed to feed. At intervals the percent mortality is determined. The
data in Table  4  indicate  that  N-formyl  loline, ergotamine (peptide type of ergot alkaloid) and
ergonovine  (clavine type  of ergot  alkaloid)  had ED50  values after 6 days of exposure  of
approximately 7.81 ug/ml. Higher concentrations produced more rapid onset of death. Ergocryptine
(peptide type)  was toxic only  at 1  ug/ml. Ergovaline (peptide type), the predominant ergot alkaloid
(40-70%) recovered from endophyte-infected tall fescue, was not available for testing.

     The broad spectrum  activity of N-formyl loline was evaluated via preliminary contact studies
with a number of other insect  species.  Loline was toxic to the cat flea (CtenocephaHdes fejis),
oat-birdcherry  aphid (Rhoaajoslphum padi), greenbug aphid (Schizaphis graminum),  American
cockroach (Periplaneta americana), adult face flies (Musca autumnaiis), larvae of Japanese beetle
(PapM japonica). and  eggs of the tobacco budworm (Helkfe Mescens). Chrome exposure to 1
ug/ml In waJeTdurlng the entire  life of the milkweed bug in the assay previously described resulted

in delayed development and reduced fecundity. In addition, 1 ug applied topically in acetone to
adult milkweed bugs is sufficient to kill 50% of the test insects after 4 days of exposure, the dose
being somewhat dependent upon the age and weight of the individual adult. An injected dose of 1
ug/adult results in approximately 50% mortality. The catbird cherry and greenbug aphids can also
be killed by ingesting lolines either from within infected tall fescue stems and leaves (the compounds
are not present on the surfaces of the plant; Eichenseer, unpublished data) or from non-infected
stems that had previously taken up the alkaloids from water (Siegel, unpublished data).

     In summary, various insects were very sensitive to purified N-formyl loline in several different
assay systems (contact, ingestion and injection). Eventually,  all the toxic chemicals produced in
infected plants will be similarly assayed and their modes of action determined. This information will
aid in understanding further the host-endophyte interaction and how this interaction can better serve
the needs of man as he uses grasses for aesthetics and conservation.
 Disease resistance

     Resistance to plant diseases by endophyte-infected grasses has not been reported. However,
 agar plate antibiosis assays have  indicated that antifungal compounds were produced in vitro by
 isolates of Acremonium spp., Phialophora-like sp. and E. typhina from various grasses (44,45, Latch
 and Siegel, unpublished data). An example of the kind of antibiosis experiment conducted by Latch
 and Siegel is shown in Figure 2 C,D. Zones of inhibition of growth of the test grass pathogen by a
 soluble factor(s) from the endophyte colonies  are  clearly evident. This experiment and others
 indicate  that a diverse range of antibiosis  exists among isolates  of E. typhina and various
 Acremonium species. Both the spectrum and amount of antifungal activity appears to be endophyte
 isolate dependent. In part, this dependency suggests the presence of fungal biotypes existing within
 the same grass cultivar or species.

     Reasons for the lack of expression of antibiosis (disease resistance) in pasture and turf Festuca
 and Lolium spp. are unknown.  It is possible that the antifungal compound(s) is produced, but not
 in sufficient quantity to control the pathogens.

     The use  of the Acremonium endophytes in turfgrasses as agents of plant protection  and
 improvement has certain unique advantages. As previously discussed, the natural association
 between the grass hosts and these endophytes is  one of mutualism  (benefits).  In addition, the
 endophytes are  propagated  with  the  plant  by  vegetative  means through  tillers  and  by
 seed-dissemination. Thus,  the endophytes can be regarded as compartments of maternally-
 inherited genetic information that can be  removed, manipulated, and re-introduced into the grass
 plant. Genes contained within this compartment include those that direct or affect production of
 loline, ergot, and peramine alkaloids and  lolitrem toxins, and  other compounds (not yet identified)
 which directly or indirectly provide enhanced resistance to insects, plant pathogens and improved
 plant growth and survival.

     Production of improved endophyte-infected grasses can be achieved  by  plant breeding
 (maternal line selection) (12) or by artificial (wounding) introduction of the endophyte into seedling
 meristem (synthetic complexes or combinations of  endophyte and  host grass) (16). The latter
 method is illustrated in Figure 2  E,F,G and can be used with naturally occurring or genetically
 modified endophytes.


Use of naturally occurring endophytes

    A number of endophyte-infected grass cultivars have been developed for insect resistance
by maternal line selection (12,29, see Funk, Chapter 18). In most cases, the endophyte is already
present in the grass cultivar, usually at a low level of infection. It then becomes a matter of selection
and increasing the number of infected tillers and plants. However, in some cases, the endophyte
must be transferred from one cultivar to another within the same plant species. The resulting cultivar
must not only contain the endophyte but  also have desirable characteristics for turf use.

    One of the current problems with the use of naturally occurring endophytes is the presence of
biotypes  which produce less of the desired beneficial  chemicals. For example, it has been
demonstrated that a biotype of IE typhina infecting Ensylva neither produces any of the  known
compounds (lolines, peramine and ergot  alkaloids)  responsible for insect resistance, nor can insect
resistance  be demonstrated using an aphid bioassay (Siegel, unpublished data). Biotypes of A
coenophialum exist which do not produce ergot alkaloids (4). Likewise, we have shown that biotypes
of Acremonium spp. exist which apparently produce varying  levels of antifungal chemical(s) in

     It is clear that considerable screening and characterization of the host-endophyte interaction
will be necessary in order to ensure that all the required chemicals are produced. By using artificial
inoculations one may be able to ensure that specific biotypes exhibiting superior performance in
one plant can be introduced into others of the same species.
Use of genetically modified endophytes

     Endophytes modified by recombinant-DNA techniques may be used to (i) enhance already
existing beneficial characteristics; (ii) introduce foreign genes which are of benefit to the plant (these
may include genes for the synthesis of antibiotics antagonistic to insects and causative agents of
grass diseases, genes for the detoxification of herbicides, or factors that enhance growth and
persistence of the host grass); and (iii) gain further understanding of how fungal-plant mutualistic
relationships  are  established  so that the genetic potential of endophyte genomes  can be
manipulated for crop improvement. Manipulation and improvement of grass endophytes by genetic
means will require elucidation of the function(s) and role(s) of secondary compounds produced in
the host-fungus interaction, particularly  with regard to  biosynthetic pathways  and effects  of
chemicals on livestock,  insects, microbes and plant growth. In addition, it will be  necessary to
develop  DMA-mediated transformation systems and  associated techniques of cloning,  gene
replacement and complementation. Development of a transformation system will, in turn, require a
knowledge of the nature and requirements of gene expression in  the endophyte as well as gene
expression of the host in response to infection, expression of disease (choke) and synthesis of
secondary metabolites.


    The mutuaiistic relationship between grasses and the Acremonium fungal endophytes provides
an excellent model system for studying the nature and expression of biologically active secondary
metabolites, molecular genetic studies, and improvement of agriculturally important grasses. These
fungi do not produce disease in their host grasses,  are obligate biotroph.c symbionte, grow in the
meristems leaf sheaths and leaf  blades of their hosts, and are  seed-disseminated. Because of

 their ecological role and life cycle, the Acremonium endophytes are ideal agents for biological control
 of insects and possibly diseases of turfgrasses and for basic studies of mutualism.

     New endophyte-infected  turfgrass cultivars with enhanced resistance to insects are now
 available. Whether they are commercially successful depends on factors discussed elsewhere in
 this book. However, because the potential is so great for turfgrass improvement, it seems that future
 use of infected cultivars will be assured, particularly if endophytes with genetically modified genomes
 are developed.
     We wish to thank authors for providing unpublished information and copies of manuscripts in
 press. Research was supported, in part, by USDA Competitive Research Grant 85-CRC-1-1533.
 This chapter is Kentucky Agricultural Experiment Station Journal Series Paper 88-11-7-3-50.

                                                                                                  grasses: A
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        Environ. Microbiol. 34:576-581 .                                                                   -**-
 3.   Bacon, C. W., Siegel, M. R. 1 988. Endophyte parasitism of tall fescue. J, Prod. Agric. 1 :45-55.
 4.   Bacon, C. W. Procedure for isolating the endophyte from tall fescue and screening isolates of it for ergot alkaloids
        Appi Environ. Microbiol. 54:261 5-261 fl
 5.   Belesky, D. P., Devine, O.  J.,  Pallos, J. E., Jr., Stringer,  W. C. 1987. Photosynthetic activity of tall fescue as
        influenced by a fungal endophyte. Photosynthetica 21 :82-87.
 6.   Bush,  L P., Gay, S. L, Johnson, M. C. 1 986. Growth and water use of endophyte-infected and endophyte-free tall
        fescue. Amer.  Soc. Agron. Ann. Meetings. Agron. Abstr. p. 140.
 7.   Clay, K. 1987. Effects of fungal endophytes on the seed and seedlings biology of Lolium perenne and Festuca
        arundinacae. Oecologia 73:358-362.
 8.   Clay, K. 1986. Grass endophytes.  In Microbiology of the Phyllosphere (J. Kokkena and J. van den Heuvel, eds.),
        pp. 188-204. England: Cambridge University Press.
 9.   Diehl,  W. W. 1950. Balansia  and the Balansiae in America. Agric.  Monogr. 4. Washington, D.  C.: US Dep. Agric.
10.   Fineran, B. A., Harvey, I. C., Ingerfeld, M. 1983. Unusual crystalloids and aggregates of tubules in the Lolium
        endophyte of ryegrass leaf sheaths. Protoplasma 117:17-23.
11.   Fletcher, L. R., Harvey, I. C. 1981. An  association of a Lolium endophyte with ryegrass staggers. H* 2L Vet. sL
12.   Funk,  C. R., Halisky, P. M., Ahmad, S. Hurley, R. H. 1985. How endophytes modify turfgrass performance and
        response to insect pests  in turfgrass breeding and evaluation  trials, in Proc. Fifth Int. Turf Res. Conf. Avignon,
        (F.  Lemaire, ed.) pp. 137-45, Versailles: INRA.
13.   Hinton, D. M., Bacon, W. C.  1985. The distribution and ultrastructure of the endophyte of toxic tall fescue. Can. JL
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14.   Johnson, M. C., Dahlman, D. L., Siegel, M. R., Bush, L. P., Latch, G. C. M. et ai 1985. Insect feeding deterrents
        in endophyte-infected tall  fescue. Appl. Environ. Microbiol. 49:568-571 .
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        perennial ryegrass and of Epichloe typhina. Plant Disease 69:200-202.
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17.   Latch,  G. C. M., Christensen, M. J., Samuels, G. J. 1 984. Five endophytes of Lolium and Festuca in New Zealand.
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18.   Latch,  G. C. M., Hunt, W. F., Musgrave, D. R. 1985. Endophytic fungi affect growth of perennial ryegrass. N, "L vL
        Agric. Res. 28:165-168.
19.   Latch,  G. C. M., Potter, L R., Tyler, B. F. 1987. Incidence of endophytes in seeds from collections of Lolium and
        Festuca species. Ann. Appl. Bjol 1 1 1 :59-64.
20.   Lewis,  D. H. 1 973. Concepts in fungal nutrition and the origin of biotrophy. BjoL Revs, 48:261 -278.
21 .   Lewis,  D. H. 1 974. Micro-organisms and plants: The evolution of parasitism and mutualism. 24th Symp, Soc, Gea
        Microbiol. pp 367-392, England: Cambridge University Press.
22.   Lewis  D H 1985 Symbiosis and mutualism: Crisp concepts and soggy semantics. In JM Biology of Mutualism
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 23.   Morgan-Jones, G., Gams, W. 1982. Notes on Hyphomycetes, XLI. An endophyte of Festuca arundinacea and the
         anamorph of Epichloe typhina. new taxa in one of two new sections of Acremonium. Mycotaxon 15:311-318.
 24.   Pedersen, J. R., Rodrigues-Kabana, R., Shelby, R. A. 1988. Ryegrass cultivars and endophytes in tall fescue affect
         nematodes in grass and succeeding soybeans. Agron. J. 80:811-814.
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         epichloe. Phytochemistry 24:1429-1431.
 26.   Pottinger, R. P., Barker, G. M., Prestidge, R. A. 1985. A review of the relationships between endophytic fungi of
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         animal performance, toxicity, and stand maintenance. Agron. J.. 78:848-850.
 28.   Rowan, P. P., Shaw, J. G. 1987. Petection of ergopeptine alkaloids in endophyte-infected perennial  ryegrass by
         tandem  mass spectrometry. N. Z. Vet. J. 35:197-198.
 29.   Saha, P. C., Johnson-Cicalese, J. M., Halisky, P. M., van Heemstra, M. L, Funk, C. R. 1987. Occurrence and
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 30.   Sampson,  K. 1933. The  systemic infection of  grasses  by Epichloe typhina (Pers.) Tul.  Trans. Br. Mycol. Soc.
 31.   Shelby, R. A.,  Palrymple, L. W. 1987. Incidence and distribution of the tall fescue endophyte in the United States.
         Plant Pis. 71:783-786.
 32.   Siegel, M.  R., Bush, L.  P., Pahlman, P. L. 1987. What am I losing by removing endophyte from tall fescue. Proc.
         43rd South. Past. Forage Improv. Conf. pp. 41-44, USPA/ARS Nat. Tech. Infor. Ser., Springfield, VA.
 33.   Siegel, M.  R., Fannin,  N., Bush, L. P., Rowan, P. 1987. Synthesis of peramine and loline alkaloids in  fungal
         endophyte-infected grasses. Ann. Meet.  Mycol. Soc. Amer. Ottawa. Abstr. 38 (p. 69).
 34.   Siegel, M.  R., Johnson, M. C., Varney, P. R., Nesmith, W. C., Buckner,  R. C., et ah 1984. A fungal endophyte in
         tall fescue: Incidence and dissemination. Phytopathology 74:932-37.
 35.   Siegel, M.  R.,  Jarlfors,  U., Latch, G. C. M., Johnson, M. C. 1987. Ultrastructure of Acremonium coenophialum.
         Acremonium loll! and Epichloe typhina endophytes in host and non-host Festuca and Lolium species of grasses.
         Can. J, Bot. 65:2357-2367.
 36.   Siegel, M.  R., Latch, G. C. M., Johnson, M. C. 1985. Acremonium fungal endophytes of tall fescue and perennial
         ryegrass: significance and control. Plant Pis. 69:179-183.
 37.   Siegel, M.  R., Latch, G. C. M., Johnson, M. C. 1987. Fungal endophytes of grasses. Ann. Rev. Phytopathology
 38.   Starr, M. P. 1975. A generalized scheme for classifying organismic associations. Symbiosis Symposia Soc. Exper.
         Biol. 29:1-20.
 39.   Weedon, C. M., Mantle, P. G. 1987. Paxilline biosynthesis by Acremonium lolii: a step towards defining  the lolitrem
         neurotoxin. Phytochemistry 26:969-971.
 40.   Welty, R. E., Azevedo, M. P., Cooper, T. M. 1987. Influence of moisture content, temperature and length of storage
         on seed germination  and  survival of  endophytic fungi  in  seeds  of  tall  fescue  and perennial ryegrass.
         Phytopathology 77:893-900.
 41.   White, J. F., Jr. 1987. The widespread distribution of endophytes in the Poaceae. Plant Pis. 71:340-342.
 42.   White, J. F., Jr. 1988.  Endophyte-host associations  in forage  grasses. XL A  proposal concerning  origin and
         evolution. Mycologia  80:442-446.
 43.   White, J. F., Jr., Bultman, T. L. 1987. Endophyte-host associations in forage grasses. VIII. Heterothalism in Epichloe
        typhina. Amer. J, Bot. 74:1716-1721.
44.   White, J. F., Jr., Cole, G. T. 1985. Endophyte-host associations in forage grasses. III. In vitro inhibition of fungi by
        Acremonium coenophialum. Mycologia 77:487-89.

45.   White, J. F., Jr., Cole, G. T. 1986. Endophyte-host associations in forage grasses. IV. The endophyte of Festuca
        versuta. Mycologia 78:102-107.

46.   White,  J. F.,  Jr.,  Cole,  G.  T. 1986. Endophyte-host  associations  in forage grasses. V. Occurrence of fungal
        endophytes in certain species of Bromus and Poa. Mycologia 78:846-850.

47.   White, J. F., Jr., Cole, G. I, Morgan-Jones, G. 1987.  Endophyte-host associations in forage grasses. VI. A new
        species of Acremonium isolated from Festuca arizonica. Mycologia 79:148-152.

48.   White,  J. F., Jr., Morgan-Jones, G. 1987. Endophyte-host associations in forage  grasses. VII. Acremonium
        chisosum. a new species isolated from Stipa eminens. Mycotaxon 28:179-189.

49.   White,  J. F.,  Jr.,  Morgan-Jones, G.  1987. Endophyte-host associations  in forage grasses.  IX. Concerning
        Acremonium typhinum. The anamorph of Epichloe typhina. Mycotaxon 29:489-500.

 50.   White,  J. F., Jr., Morgan-Jones, G. 1987. Endophyte-host associations in forage grasses. X. Cultural studies on
         some species of Acremonium Sect. Albo-Lanosa, including a new species, A. starrii. Mycotaxon 30:87-95.


                                TABLE 1
Acfemonium FungaJ Endophytes of Grasses.
       Fungus                          Grass                      Refa

  Epichloe typhina       Lolium. Festuca. Agrostis. Dactylis,    (9,23,
  (Acremor.ium typhinum) Holcus. Hordeum. Poa. etc.                 49)

  A.  coenophialum        £. arundinacea, P_. autumnal is           (23,50)

  A.  lolii               L. perenne                              (17)

  A.  huerfanum           ][. arizonica  (Colorado)0                (47)

  A.  chisosum            Stipa  eminens                           (48)

  A.  starrii             £. arizonica  (Texas)0,                  (50)
  ""                      Bromus anomalus,  F_. obtusa,
                         F. subulata

  * References  for  name  of fungus  and  species of  infected grass.

  b Fungus isolated from the  populations found  in Colorado or Texas.

                                            TABLE 2
      Characterization of  the association  between  Epichloe  typhina and related  Acremonium
 endophytes and their grass hosts3.
Z flowering
Association panicles shoving
No . symptoms Fungus
1 I 98 E. typhina

2 1-10 E. typhina
3 0 Acremoniun spp.

Type of population
Association infected
Pathogenicb > 98

Pathogenicb 50-70
or mutualistic
Mutualistic * 90

Spread by clonal growth
of host and ascospore

Spread by clonal growth
of host , seed and
ascospore infection
Spread by seed and
clonal growth of host
Several sub-
families of
Poaceae and

   8 Adapted from White (42).

   b Same as parasitic in the sense of Lewis (21) and Siegel et al.  (37).  The term agonistic is now suggested by
     Lewis (22).

   c Listed in order of importance.

                                               TABLE  3
     Biologically active compounds isolated from endophyte-infected Festuca and Lolium species
of grassesa.
Chemical (grass)b
Ergot alkaloids TF.PRG,
Loline alkaloids TF
Peraaine alkaloids TF.PRG,
Lolitreras & PaxillineS PRG
Tetraenone steroid TF
• Summary of data from Ref. 1,3,
b Abbreviations: TF, tall fescu
(L. perenne) ; CF, Chewings and
coenophialum; A.I., A. lolii,
Average Distribution in
amount (pg/g) plant6 Produced
Orig1n drv wt — - 	 . . i..
(fungus)b»c in plantd Roots Stems Leaves culture toxicity
A.c.,A.l., 3-10 (TF) ND
A.c. 2,000 (TF) +f
A.C..A.1., 5-25 (PRG)
E.t., E.t.
A.I. 3-25 (PRG) ND
A.c. ND ND
4,37 and unpublished data of Siegel,
e (F. arundinacea); HF, hard fescue
creeping fescue (F. rubra coramutata
E.t., Epichloe typhina.
+ + Yes Insect & mammalian
+ + No Insect
+ +• Yes Insect
+ 4- No, Yes Insect & mammalian
ND ND Yes Microbial & mammalian
Latch and Bacon.
(F. longifola); PRG, perennial ryegrass
and F. rubra litorales); A.c., Acremonium

   c Refers to the fungus which infects  the grass listed in the previous column;  i.e., A.c. infects TF, E.t.  infects
     HF,  etc.

   d Average amount in the grass listed  in parenthesis, includes vegetative parts and seed.

   e ND,  not determined; -, not present; +, present.

   f 10-15Z of total loline found in plant (Bush, unpublished data).

   8 Paxilline is a precursor of lolitrem B and is produced in both culture and the plant, whereas only lolitrem B has

     been detected in the plant (39).

                                      TABLE 4
    Percent mortality of Oncopeltus fasciatus (large milkweed bug) offered either N-formyl loline
or various ergot alkaloids in water3
Concentration (Mg/ml)




Compound 1000
N-Formyl Loline














     Methods used the  same as in Johnson et al.  (14).

                                         FIGURE 1
     Generalized  life cycles of grass endophytes.  Question Mark (2); indicates that  uncertainty
exists as to the role of ascospores in the life cycle of these organism (e.g. E. typhina) as well as to
the mode of infection (via stigma) (adapted, in part, from Ref. 1). Solid arrows: endophytes that are
seedborne as in the Festucoideae grasses and in cleistogramous Balansiae-infected seeds. Broken
arrows: transmission of endophytes via spores, in the case of Ephicioe typhina ascospores, from
stromata of infected plants.
                                          Fungus Ge
                                         Through Sti
                                                              In Seed
       Fungus Germ
      Enters Stigma (?)
                                               into Ovule
                                                                 Active Mycelium
                                                                 Grass Seedling
Germinating Spore
                                              Enters Flower
                         (Ascospores, Conidia)
                            at Flowering (?)
                                       Active Endophytic
                                      Mycelium in Seedling
                                       (Stem Tissue and
                                         Leaf Tissue)

                                      FIGURE 2
     A, component parts of milkweed bug (Oncopeltus fasciatus) antibiosis assay (plastic cup, plug
of dental cotton and cardboard top). B, assembled assay, includes 5 nymphs. C and D, antibiosis
assay for chemical activity of various endophyte isolates. Photographs are of the underside of agar
plates. Test grass pathogen growing from center of the  plate, Rhizoctonia cerealis.  Endophyte
isolates of Acremonium coenophialum place on the periphery were isolated from tall fescue: 9, Ky
31; 10, Kenhy; 11, Fawn; 12, Alta; 13, unknown tall fescue cultivarfrom NZ; 14, Ky 31. Acremonium
lolii isolated from: 15, Nui. Acremonium starrii isolated from: 16, Festuca arizonica. E, F,  G: Artificial
inoculation of one week old seedlings. Arrows indicates position of the meristem, wounded meristem
and meristem inoculated with mycelium of the endophyte. Seedlings grown on water agar (2%) and
wounding operation done under a stereo microscope using a scalpel, with disposable  blade (see
Ref. 16 for the detail).

                              OF GRASSES:
                            SPECIFIC TOXINS
                                  Charles W. Bacon
                      Toxicology and Mycotoxlns Research Unit
                    Richard B. Russell Agricultural Research Center
                                   P.O. Box 5677
                               Athens, Georgia 30613
    The ecological necessity for an intimate association of a fungal endophyte with a grass is
suggested by the widespread occurrence of these two vastly different organisms as a composite
system (1,2,3). Fungal grass endophytes include species of Acremonium. Epichloe. and Balansia
(Clavicipitaceae , Ascomycetes) that live within and are associated intimately with various species
of grasses and sedges. The compatible nature of this relationship (4,5), as well as data from various
laboratories led Siegel et al. (6) and Bacon and Siegel (7) to conclude that this association was a
mutualistic symbiosis. The fungus receives nutrients  from  the grass, and is  protected  and
disseminated. Infected  grasses  benefit by increased growth (8,9,10), reduced predation from
vertebrate and invertebrate herbivores (11,12,13), and drought tolerance (14). Additional benefits,
while observational, include disease resistance  and stress  sparing mechanisms (15,14). Before
we  can completely define the symbiotic nature and  ecological success of endophyte-infected
grasses, field data reflecting physiological responses of infected grasses to strenuous environmental
stresses are needed. Nevertheless, it is the use of ecological benefits derived from the association
that is the current focus of research.

    Researchers are attempting to transfer endophytic fungi into grasses, primarily conservation
and turf grasses, many species of which are not natural  hosts. Benefits from these infections are
expected to include  increased pest resistances, improved appearance, and tolerance to
environmental stresses. There are many potential uses for such symbiotic systems, but they may
be grouped under two broad classes: biological controls for grass growth, stamina and appearance;
and biological control for pests on grasses. Fungal endophyte-infected grasses are unique in that
they are one of few biological controls that can be used, in addition to deterring pest, for controlling
the  morphology and stamina of a group of plants so essential to man's environment and health.

    Use of  infected grasses  requires  complete understanding  of  the  in vitro and  in  vivo
requirements for the fungus relative to predicting  its performance when transferred to non-host
grasses. After having accomplished infecting non-host grasses, experiments designed to determine
agronomic performances of the infected grasses should  pose no problem. However, when we try
to attribute specific performance aspects  of infected grasses to either the grass, fungus, or both
we  are faced with an experimental dilemma. The problem is compounded when we want specific
information related to the fungus as a potential for forage improvement. Working with isolated fungus
involves problems of defining and maintaining in vitro the desired in vivo characteristics. Thus, there
is a  need to 1) develop laboratory techniques for culturing the endophyte  in vitro ; 2) develop media
which will characterize and maintain useful specific physiological strains of the endophyte; and 3)
develop techniques for transferring the endophyte to the desired grass species.

     It is my intention to discuss the first of these two research needs, and to describe results of
studies which established that while these fungi are varied and genetically unstable upon isolation,
their in vitro culture may still be used to experiment with in situ resistance mechanisms after transfer
to grasses. The infection of grasses, developed by Latch et al. for grass seedlings (16, and see
companion chapter by Siegel et al. this proceeding), will not be covered. The discussion will center
mainly around the endophytes of tall fescue and/or perennial ryegrass since these two are of
considerable economic importance, and are the major focus of attention by various endophytologists.
A more detailed discussion on morphology and taxonomy, and host parasite relationships of these
two endophytes as well as other species of endophytes can be found in recent reviews (6,7,17,18)
and in the chapter by Siegel in these proceedings.

                               ISOLATION OF FUNGI

     The fungi (Table 1) may be isolated from either recently collected field or greenhouse grown
material. Most endophytic fungi are located in the sheath portion of a grass leaf and it is an inner
sheath that should be used since it is relatively free of debris and saprophytic fungi. For those fungi
that  are not located in leaves,  it would behoove one to use the inner, least exposed plant tissue
since it too will be free of debris.  Material intended as a source for endophytes should be used
immediately or stored under refrigeration  (4 C) in tissue paper dampened  with sterile water, but
only for a few hours.
     Small sections of sheaths are sterilized in full strength commercial bleach, rinsed in sterile
water, cut into smaller sections (Table 2) and placed in either liquid medium or agar isolation media
(Table 3). Additional  isolation procedures have been reported  for other endophytes and include
such starting  material as ascospores (19), and seed (16). The speed of isolating the fungus from
grass tissue depends on tissue type and its preparation, genetic characteristics of each fungus and
isolation media. The  total time will vary from as early as 2 weeks on the liquid medium to as late
as 6 weeks on the agar medium. Agar medium is solid and on solid media nutrients are more limited
due to reduced diffusion of growth requiring compounds. Generally fungi producing choke symptoms
(see chapter by Funk, this proceeding) will  grow faster than  nonchoke inducing species.  This
possibly reflects a difference in the nutritional fastidiousness of the two basic groups.

     Once isolated, grass endophytes can be stored on either corn meal-malt agar or M102 medium
(Table 3). Fungi may be stored under refrigeration only if they are freshly isolated and  producing
spores. Spores can survive the storage temperatures frequently  used to preserve fungi (-20 to 0
C). Older nonsporulating isolates can be safely stored under warmer temperatures (4 to 10 C), or
at room temperatures (20 to 26 C). Storage at room temperature is particularly recommended for
those isolates that are nonchoke inducing as they rapidly loose the ability to produce spores. I have
had no success with storage of endophytes on substrates traditionally used  for fungi, i.e. silica gel,
soil,  etc.

     The exact in vitro growth requirements of endophytic fungi have not been established. Most
media are nondefined and complex and at best semisynthetic (19,20,21). One isolate of the
endophyte of fescue was induced to grow on defined and relatively simple media after it was
maintained in the laboratory for  a considerable  period of time (20,21). In another  group of
endophytes, Balansia which are associated primarily with weed grass species, a defined medium
has been used to culture five species (22). I have not had any success using these defined media
for initially isolating fungi from grasses. However, once  endophytes have  been isolated using a
complex media of choice, defined media (20,21, 22) may be tried.

     Regardless of the media selected, shake culture of liquid media is favored over stationary
culture when it is desired to obtain a rapid growth of fungus. Once maximum amount of growth is

produced, the culture may be continued as stationary cultures where several secondary products
are produced (see below).


     After an endophyte is isolated, it may be tested for the synthesis of specific substances on a
specific culture medium.  If one is trying to determine whether an isolate is toxic to cattle, or to
insects, the procedure to follow should include a two-stage fermentation (Table 4) with the addition
of specific substrates which are considered possible precursor for inducing the synthesis of specific
metabolite, e.g. tryptophan for ergot alkaloids (Table 4). An alternative is to use either liquid or agar
media to culture endophytes and use it directly to determine toxicity using one of many insect feeding
bioassays (11,12,13). Of course negative  bioassay results need not  mean  that an  isolate is
biologically inactive. Rather, it may mean that the in vitro requirement is not met. An in vitro test of
isolates should be taken  to mean that  under test  conditions  they are  either producing  or  not
producing the desired compound. However, work on species of Balansia established that qualitative
production of ergot alkaloids occurred both in vivo and in vitro (19). This same corollary was
established for the endophyte of tall fescue (23,24,25), and is suggested  from the work of Rowan
et al. (13) for the production of peramine by the ryegrass endophyte. Concern for only mammalian
need only be considered if the intended endophyte is for agronomic improvement of forage grasses
and  not conservation and turf grass species.

     The competence  of an endophyte to produce the desired biologically active compound should
be done on the initial isolate as this ability may not be stable in culture, e.g. ergot alkaloids, Table
5. It  is not known if in fact this loss in biosynthetic potential for a substance is restored to an isolate
upon re-infecting it into grass material. Work on this aspect of the endophytes is being done (Siegel
and  Bacon, unpublished). An alternative procedure for working with endophytes is to obtain single
spore isolates of the initial fungus. This  procedure,  while tedious, might lead to the selection of
colonies that are superior or equal to the  initial isolate, and contain one basic nuclear type. Such
colonies should be stable for a considerable period of time, allowing for strain improvement using
any  of the processes, e.g. protoplast fusion, mutagenesis.

                           SECONDARY METABOLISM

     This section will center on the production of several biologically active compounds which are
secondary metabolites and whose intended use makes grass endophytes economically attractive.
These compounds consist of a variety of chemically complex and structurally unrelated substances
that  have  been associated with grasses, fungi and endophyte-infected grasses (Table 6). For the
most part, compounds produced  by endophytic fungi are alkaloids and they may or may not have
the same biogenetic precursors since they have such diverse chemical structures. Of course there
may be many more unknown secondary metabolites than currently reported, but the ones that are
known are all produced from only a few  biochemical intermediates of primary metabolism  (Table
6). The compounds selected for inclusion in this table are those that were either studied in the past
and  related to some aspect of cattle toxicity, synthesis by the fungus in culture,  or associated with
some economic aspect of the infected grass.
     Control of the biosynthesis of compounds  availability of precursors. As is the case for the in
situ origin  of the final infected grass product, the origin of intermediates used in their biosynthesis
might priginate from the grass and/or the fungus. It must also be considered that the fungus might
produce one portion of the molecule, and the grass chemically modifies  it, as suggested for the
synthesis of the neurotoxin, lolitrem B, found in infected perennial ryegrass (31). Table 6 lists, where
possible, the class of compounds grouped according to the precursor biosynthetic origin for fungal


secondary metabolites following Turner's scheme  (32) which may be useful for adding inducer
substrates when formulating media to test for biosynthesis of specific classes of compounds.

     Only recently have attempts been made to demonstrate whether substances are produced
by the fungus independently of the grass and the reverse. Table 6 also lists those compounds that
have been  reported  to occur  in grasses whose infection status was unknown. Attempts to
demonstrate that endophytes alone can make some of the major biologically active compounds in
culture have failed, but these negative data may only mean that the culture conditions have not
been met. It has been established that one of these, loline, is produced only in infected tall fescue,
while another, perloline, is produced by both infected and noninfected grasses.

     The  media used for isolating and growing endophytes all have a high carbon to nitrogen ratio,
and this ratio can vary within a range of 100 to 10, particularly for vegetative growth. I have found
that this ratio is not optimum for the production of classes of secondary metabolites that are, at least
partially, under nutritional control. One such class of compounds is the ergot alkaloids in which the
qualitative and quantitative levels produced on media occur when the carbon to  nitrogen ration is
reversed  in the direction of higher nitrogen. In addition to this ratio, media may be used where the
form of nitrogen supplied is such that the rate of its utilization is slow. This suggest that the control
mechanism for this class  of compounds may involve nitrogen catabolite repression (27), as has
been suggested for the mechanism for ergot alkaloid synthesis by a closely related fungus Claviceps
sp. (28).

      As indicated above, a characteristic of media useful for detecting secondary metabolites is the
very slow growth rate. Slow growth rate is not only a factor of media, but also an inherent quality
of each  isolate. For the  most part, ergot  alkaloid-producing isolates that  grow the slowest, but
sporulate the most are the highest ergot alkaloid producers. This statement  is based on data using
endophytic species of Balansia (19,22). Information is not available one other endophytes to
supports  this generality.

      Yates (29) has reviewed and he is indeed a leader in the research on the isolation and chemical
identification of alkaloids and other substances isolated from tall fescue grasses.  Garner et al. (30)
have developed useful cattle toxicity bioassays  for determining the activity of most compounds
reported by Yates. In addition to these excellent reviews, a spectrum of biological activities for these
and other compounds, as well as current bioassays can be found in the chapter by Siegel et al. (this

      In the grass-fungus situation the environment is also expected to influence both the production
of secondary metabolites and  hence any associated animal pest, or fungus  disease defense
mechanism. Such environmental influences on the accumulation of secondary metabolites by plants
(33,34),  and in endophyte-infected tall fescue  (13) are documented. These studies have only
examined the effects of nitrogen and its interaction with soil moisture on the accumulation of ergot
alkaloids, but similar effects should exist for other economically interesting  metabolites.  It has not
been established which essential plant nutrient is more responsible for a particular  metabolite
associated  with a desirable feature of infected  grasses.  A complex interaction is probably
responsible for the reaction of infected grasses to any stressful situation.

     The  performance of infected grasses for any stress sparing mechanism should be measured
under severe environmental conditions. Most studies have measured the performance of infected
grasses under greenhouse conditions of constant temperature and moisture. Such ideal conditions
will  never differentiate between survival values and  other effects of the endophyte  on grass
performance. Studies  of infected grasses under severe environmental conditions  can establish the
value of an endophyte for use  in other forages. A word of caution concerning this theoretical

approach is that The ecological success observed in naturally infected hosts may not be realized
in synthetically infected hosts. It may be simpler to select naturally infected grasses and improve
these for whatever desired character. Nevertheless, once identified, specific endophytes can be
isolated and studied as described above; the continued use of specific endophytes will establish
the utilitarian value of each endophyte for improved performance of nonhosts.

     It is also important to use several cloned infected and noninfected grass material if at all
possible since studies of such material might indicate differences due to infection, and not to the
genetic makeup of different seed sowed seedlings.  Studying cloned material should also identify
grasses with superior tolerances to severe  environmental factors, and which  when  infected by
endophytes might produce an even  better grass. Furthermore, it is important  to study  the
performance of a variety of clones, since the work of Arechavaleta et al. (13) suggested and Belesky
et al. (35) established that for each environmental factor, the behavior of each cloned will differ. The
important point to remember is that the fungus apparently influences or exaggerate the basic genetic
makeup of each grass.

     The most important outgrowths of research devoted to etiologies of pasture grass toxicity (for
 review see 17) was establishing that the nature of the relationship of a fungus and its grass hosts
 was nonpathogenic, and that the fitness of infected grasses was improved. If indeed the fungus
 only modifies the basic physiology of the grass, it implies that there is in the basic genetic makeup
 of each grass species, a cultivar that is inherently superior without an endophyte.

     Improved fitness observed in endophyte infected grasses indicates that ecologically we find
 yet another example of a mutualistic symbiosis. The nature of the benefits are still circumstantial,
 but then too so are many other mutualistic symbioses. The association of endophytes and grasses
 fits Smith and Douglas's definition as an interceliullar mutualistic endosymbiosis (36). This is a
 purely morphological definition and its use here reflects what is currently known with complete

     Research should continue into the use of endophytes as biological controls for pests and for
 improved performance of grasses under stressful conditions. It is very seldom that such a biological
 system presents itself that will confer both pest resistant and stress resistant mechanisms. The fact
 that such a system is self-perpetuating, contained, and stable is all the more reason  to use it. The
 present information on the variety of natural pest deterrents produced within the association predicts
 that there are obvious benefits derived from identifying the responsible agent, defining the nature
 of any stress sparing mechanisms, and using these for control processes in other plants.

1.   W. W. Deal. 1950. Balansia and Balansiae in America. Agriculture Monograph No. 4. U.S. Department of Agriculture.
        U. S. Government Printing Office, Washington, DC, 82pp.
2.   G. C. M. Latch, M. J. Christensen, and G. J. Samuels. 1984. Five endophytes of Lolium and Festuca in New Zealand
        Mycotaxon 20: 535-550.
3.   J. F. White and G. T. Cole. 1985. Endophyte-host associations un forage grasses. I. Distribution of fungal endophytes
        in some Lolium and Festuca sp. Mycologia 77: 323-327.
4.   D. M. Hinton and C. W. Bacon. 1985. The distribution and ultrastructure of the endophyte of toxic tall fescue. Can.
        J. Bot. 63: 36-42.
5.   M.  R. Siegel, U. Jarlfors, G.  M. C. Latch and M. C. Johnson.  1987. Ultrastructure of Acremonium coenophialum.
        Acremonium lolii. and Epichloe typhina endophytes in host and nonhost Festuca and Lolium species of grasses.
        Can. J. Bot. 65: 2357-2367.
6.   M. R. Siegel, G. M. C. Latch and M. C. Johnson. 1987. Fungal endophyte of grasses. Ann. Rev. Phytopathology 25:
7.   C. W. Bacon and M. R. Siegel. 1988. Endophyte of tall fescue. J. Production Agric. 1: 45-55.
8.   G. C. M. Latch, W. F. Hunt and D. R. Musgrave. 1985. Endophytic fungi affect growth of perennial ryegrass. N.Z. J.
        Agric Res. 28:165-168.
9.   J. C. Read and B. J. Camp. 1986. The effect of the fungal endophyte Acremonium coenophialum in tall fescue on
        animal performance, toxicity and stand maintenance. Agron. J. 78: 884-850.
 10.   K.  Clay. 1987.  Effects of fungal endophytes on the seed and seedling biology of Lolium perenne and Festuca
        arundinacea. Oecologia 73:358-362.
 11.   D. L. Gaynor and W. F. Hunt. 1983. The relationship between nitrogen  supply, endophytic fungus and Argentine
        stem weevil resistance in ryegrasses. Proc. N. Z. Grassland Assoc. 44: 257-263.
 12.   M. C. Johnson, D. L. Dahlman, M. R. Siegel, L. P. Bush, G. C. M. Latch, D. A. Potter, D. R. Varney.  1985. Insect
        feeding deterrents in endophyte-infected tall fescue.  Appl. Env. Microbiol. 49: 568-571.
 13.   D. D. Rowan and D. L. Gaynor. 1986. Isolation of feeding deterrents against Argentine stem weevil from ryegrass
        infected with the endophyte Acremonium loliae. J. Chem. Ecol. 12: 647-658.
14.   M. Arechavaleta, C. W. Bacon, C. S. Hoveland and D. E.  Radcliffe. 1988. Effect of the tall fescue endophyte on
        plant response to environmental stress. Agron. J. Accepted.
15.   J. F. White and G. T. Cole.  1985. Endophyte-host association in forage grasses. III. In vitro inhibition of fungi by
        Acremonium coenophialum. Mycologia 77:487-489.
16.   G.  M. C. Latch  and  M. J. Christensen. 1985. Artificial infection of grasses with endophytes. Ann. Appl  Biol 107'
17.   C. W. Bacon, P. C. Lyons, J. K. Porter and J. D. Robbins. 1986. Ergot toxicity from endophyte infected grasses: a
        review. Agra. J. 78:106-116.
18.   K. Clay.  1986. Grass endophytes. Pp. 188-204 in: N.  J. Fokkema J. van den Heuvel,  eds., Microbiology of  the
        Phyllosphere. Cambridge University Press, London.
19.   C. W. Bacon, J. K. Porter and J. D. Robbins. 1979. Laboratoryproduction of ergot alkaloids by species of Balansia
        J. Gen. Microbiol. 113:119-126.                                                                      '
20.   N. D. Davis, E.  M. Clark, K. A. Schrey and U.  L.  Diener. 1986. In vitro growth of Acremonium coenophialum. an
        endophyte of toxic tall fescue grass. Appl. Environ. Microbiol. 52: 888-891.
21.   R. K. Kulkarni and B. D. Nielsen. 1986.  Nutritional  requirements for growth of a fungus endophyte of tall fescue
        grass. Mycologia 78: 781-786.

22.   C. W. Bacon. 1985. A chemically defined medium for the growth and synthesis of ergot alkaloids by species of
        Balansia Mycologia 77:418-423.

23.   J. K. Porter, C. W. Bacon and J. D. Robbins. 1979. Ergosine, ergosinine and chanoclavine I from Epichloe typhina.
        J. Agric. Food Chem. 27:595-598.

24.   P. C. Lyons, R. D. Planner, and C. W. Bacon. 1986. Occurrence of peptide and clavine ergot alkaloids in tall fescue.
        Science 232: 487-489.

25.   S. F. Yates, R. D. Plattner and G. B. Garner. 1985. Detection of ergopeptine alkaloids in endophyte infected toxic
        tall fescue by mass spectrometry/ mass spectrometry. J. Agric. Food Chem. 33:719-721.

26.   R. A. Prestidge,  D. R. Lauren, S. G. van der Zijpp and M. E. Di  Menna. 1985. Isolation of feeding deterrents to
        Argentine stem weevil in cultures of endophytes of perennial ryegrass and tall fescue. N. Z. J. Agric. Res. 28:

27.   J. D. Bullock, R.  W. Detroy, Z. Hostalek, and A. Munim-al-shakarchi. 1974. Regulation of secondary biosynthesis
        in Gibberella fujikuroi. Trans. Br. Mycol. Soc. 62:377- 389.

28.   J. Kybal, E. Kleinerova and V. Bulant. 1976.  Ergot alkaloids.VI. Nitrogen metabolism during the development of
        sclerotium of Claviceps purpurea. Folia Microb. 21:474-480.

29.   S. G. Yates. 1983. Tall fescue toxins. Pp. 249-273 in: M. Recheigel, ed., Handbook of naturally occurring food
        toxicants. CRC Press, Boca Raton, Fl.

30.   G. B. Garner and C. N. Cornell. 1878. Fescue foot in cattle. Pp. 45-62 in: T. D. Wyllie and L G. Morehouse, eds.,
        Mycotoxic Fungi, Mycotoxins, Mycotoxicoses, vol. 2. Marcel Dekker, Inc., N. Y.

31.   W. M. Christopher and P. G. Mantle. 1987. Paxilline biosynthesis by Acremonium loliae: a step toward defining the
        origin of lolitrem  neurotoxins. Phytochemistry 26:969-971.

32.   W. B. Turner. 1971. Fungal Metabolites. Academic Press, N. Y. 446 pp.

33.   G. C. Marten, A. B.  Simons and J. R. Frelich. 1974. Alkaloids of reed canary grass as influenced by nutrient supply.
        Agro. J. 66:363-368.

34.   G. R. Waller and E. K. Nowaki. 1978. Alkaloid Biology and Metabolism in Plants. Plenum Press,  N. Y. 294pp.
35.   D. P. Belesky, O. J. Devine, J. E. Pallas, Jr., and W. C. Stringer. I987. Photosynthetica 21: 82-87.

36.   D. C. Smith and A.  E. Douglas. 1987. the Biology of Symbiosis. Edward Arnold Publishers, London 302pp.

                                            TABLE 1
      Choke inducing and nonchoke inducing grass endophytes cultured on media and which may
 be useful for transferring to agronomically important grass species.
                                Endophytes*             Grass Hosts**
                                 Epichloe typhina          Festuca rubra
                                 E. typhina                F. longifolia
                                 E. typhina                 F. ligulata
                                 E. typhina              Lolium perenne
                                 E. typhina            Spenopholis obtusata
                          Acremonium coenophialum     Festuca arundinacea
                                   A. lolii                  L. perenne
                               Acremonium sp.              F. versuta
 'Most species of Epichloe are considered choke inducing when infecting their hosts (and see chapter by Funk, this book).

 **Natural hosts.

                                 TABLE 2

                     Procedure for Isolating Grass Endophytes
                   A. GRASS TISSUE-ENDOPHYTE, 2.54 cm sections
                    B. STERILIZE, FULL-STRENGTH BLEACH, 5 min
*The two basic endophytes, Acromonium typhinum and A., coenophialum. may be identified on
media following published descriptions(2).

                                     TABLE 3
                      Media Used to Isolate and Culture Endophytes
Isolation Agar
Malt extract
Yeast extract
Corn meal agar
Distilled water


10.0 g
1.0 g
0.05 g
1000 ml

Malt extract
Yeast extract
30.0 g
20.0 g
2.0 g
1.0 g
0.5 g
0.5 g
1.0 g
Chloramphenicol 0.05 g
Distilled water
1000 ml
                                pH adjusted to 6.0 with NaOH

                                        TABLE 4
     Two  stage  fermentation  procedure  for  choke  inducing and nonchoke  inducing  fungal
endophytes of grasses.
                                   Fescue Tissue-Fungus
                 Complex Medium, e.g. M102, and 4 wks Shake Culture, 24 C
                                 Alkaloid Producing Medium:
                                   Sorbrtol             50 o g
                                   Glucose            10.0 g
                                   Glutamic acid        10.0g
                                   KH PO             0.5 g
                                   MgSO              0.3 g
                                   Yeast extract        1.0 g
                                   Tryptophan          0.8 g
                                   Distilled water     1000 ml
pH 5.6 adjusted with 10 N NaOH; incubate first as shake cultures at 24 C, then as stationary cultures (15-24 C) for 2 to
4 months.

                                          TABLE 5
     Stability of Ergot Alkaloid Producing Strains of Tall Fescue Endophyte during Culture
                                          Total Ergot Alkaloid (mg/l)*
             Strain          Initial          5          10          15          25
                                  'Values are means of four replicates

                                                TABLE 6
      Major Classes of  Secondary  Metabolites  Isolated from Toxic Grasses  whose Endophyte
Infection Status were or were not Known at Time of Chemical Isolation.
                Chemical Class*
A.   Indole derivatives

   1.   Simple indoles
Erythro-1 -(3-indolyl)propane-1,2,3-triol, 3-indole     Species of Balansia
acetic acid, ethyl-3-indole carboxylate, indole ethanol,
w-indole acetamide (also see single amino acid
   2.   Lysergic acid amides
Ergovaline, ergotamine, ergosine, ergosinine,
ergonovine, etc.
Balansia spp., endophytes
of tall fescue, perenial
ryegrass, and these infected
   3.   Prenylated indoles
Lolitrems A, B, C, and D, Paxilline
Perennial ryegrass
               (lolitrem  B)
*Chemical classes following the scheme of Turner (32).

                  Chemical Class*
B.   Triterpens and Steriods
    1/.    C& Sterols
ergosterol peroxide
Infected fescue and cultures
of A- coenophialum
 C.   Pyrrolizidlne alkaloids
N-formylloline, N-acetylloline, and demethyl-N-
Infected tall fescue
 D.   Amlno acid derivatives
    1.   Single amino acid
Harmane, perlolyrine, norharmane, Halostachine     Tall fescue
    2.   Two amino acid derivatives
                 8    7
                (1) R  = H
                (2) R  = Ac
A. lolii. A. coenophialum.
infected tall fescue and
perennial ryegrass
'Chemical classes following the scheme of Turner (32).

                  Chemical Class*
 D.   Amino acid derivatives (Continued)

   3.   Miscellaneous amino acid derivatives
perlolidine, perloline
Infected and noninfected
tall fescue and perennial
*Chemical classes following the scheme of Turner (32).


                  PERFORMANCE  OF  GRASSES

                 C. R. Funk, B. B. Clarke, and J. M. Johnson-Cicalese

                     New Jersey Agricultural Experiment Station
                                Rutgers University
                         New Brunswick, New Jersey 08903
    Grasses used for turf and conservation are exceedingly important in our efforts to enhance
and beautify the environment, preserve and improve our precious soil  resources, and provide
recreation and enjoyment for all people. Improved cultivars are currently being developed to produce
attractive, durable, and persistent turfs with reduced establishment and maintenance costs. Grasses
exhibiting increased stress tolerance, improved  insect and disease resistance, reduced pesticide,
fertilizer, water, and mowing requirements, and  better turf forming properties will also be of great
benefit. We also need grasses adapted to poor soils, shade,  heavy wear, close mowing, and other
specialized uses and environments.

    Turfgrass breeders have recently begun utilizing endophytic fungi (primarily Acremonium spp.)
in their efforts to develop grasses with improved insect resistance and increased stress tolerance.
In  many instances,  Acremonium  endophytes living within  the tissues of tall fescue  (Festuca
arundinacea Schreb.), perennial ryegrass (Lolium perenne  L), hard fescue (FL longifolia Thuill.)
Chewings fescue (F. rubra L. subsp. commutata Quad.), and perhaps  many other grasses have
significantly modified host plant performance. Although plant scientists have been aware of the
presence of endophytes in many grasses for  over 100 years, endophytes received very little
attention until recently when a number of sign iicant discoveries were made. These included: (1)
instances of poor performance when animals g< azed on endophyte-infected perennial ryegrass and
tall fescue, (2)  reports of insect resistance in many endophyte-containing grasses, and (3)
suggestions of improved growth,  summer survival, and stress tolerance of grasses containing

    Animal health problems associated with endophyte-produced toxins have prompted programs
to eliminate the fungus from new cultivars and seed lots of tall fescue, an important pasture grass.
On the other hand, dramatic instances of improved insect resistance, persistence and performance
have been observed in endophyte-containing plants. Thus, the Acremonium endophyte is generally
considered to  be a desirable attribute in grasses  grown for turf and conservation.

                               INSECT RESISTANCE

     New Zealand scientists (Prestidge et al., 1982) were the first to report that an endophytic
fungus, Acremonium lolii Latch, Christensen, and Samuels, was associated with resistance to the
Argentine stem weevil,  Listronotus  (=  Hyperodes) bonahensis Kuschel  in perennial  ryegrass.
Several toxins have since been associated with the presence of endophytes and are believed to
be responsible for the enhanced insect resistance (Bacon  et aL (Chapter  17). Larvae of the
Argentine stem weevil, a small billbug-like insect, can cause extensive damage to perennial ryegrass
and many other grasses  used for pasture, turf and conservation in New Zealand and several other
countries of the southern  hemisphere (Stewart, 1986 and 1987). Larval damage is especially severe
during hot, dry summer months resulting in extensive tiller loss, apparent drought  stress, and slow
fall recovery.  In fact, endophyte-free  plants seldom persist in old pastures and turfs in many parts
of New Zealand because they are crowded-out and replaced by perennial ryegrass plants containing
the Acremonium endophyte.

     Although adult Argentine stem weevils cause only minor damage to established grasses, they
can  inflict severe damage during the  seedling establishment stage.  Again, the  Acremonium
endophyte confers a high level of resistance. Interestingly, even old ryegrass seeds containing
nonviable endophyte, produce seedlings resistant to stem weevil feeding for a few days following
germination and emergence (Stewart, 1985).

     Resistance of perennial ryegrass to lepidopterous sod webworms has also been associated
with the presence of the Acremonium endophyte. This important insect  pest damages many turf
and  conservation grasses, especially in regions with warmer summers.  The larvae spend the
daylight hours protected  in silken underground tunnels. During the night they feed extensively on
grass  leaves, primarily during late summer and early autumn. In  a New Jersey trial (Funk et al,
1983), perennial  ryegrasses rated as highly resistant to sod  webworms were  shown, through
microscopic examination and enzyme-linked immunosorbant assay (ELISA), to contain a very high
percentage of endophyte-infected plants. Ryegrasses exhibiting substantial  injury from larval
feeding, however, were  free or mostly free of the endophyte.  Field resistance to sod webworms
was expressed both as a 10-fold reduction in larval feeding and a nearly complete absence of larvae
from the soil  beneath  endophyte-containing  plants.  The  maternal transmission of sod webworm
resistance was very striking in that single-plant progenies descending from the same mother line
were  either all resistant or all susceptible.  Maternal transmission of endophyte-mediated  pest
resistance occurs because almost all seed produced from an endophyte-infected plant contains the
endophyte. We have not observed any evidence of pollen transfer. The role of endophytes in
conferring resistance to various species of sod webworm in other grasses needs further study.

     Billbugs   (Sphenophorus spp.)  can seriously  damage  many grasses  used  for turf and
conservation, especially  under conditions of drought stress during mid-summer. Adult billbugs, like
the Argentine stem weevil, lay their eggs in  the base of grass tillers during early summer. Upon
hatching, the  young larvae feed within the tiller and later upon adjacent plants  immediately below
the soil surface. Subsequently, wilted or dead grass tillers can be easily pulled from the soil exposing
insect frass and feeding  injury at the base of each tiller. Billbug injury, while easy to diagnose, is
frequently mistaken for  summer drought  or disease injury.  Moreover  the more open turf  and
subsequent warmer, drier microclimate created by billbug damage makes conditions very favorable
for additional damage by chinch bugs (Blissus leucopterus hirtus Montandon). Endophyte-enhanced
resistance to billbugs has been observed in a number of perennial ryegrass field trials in New Jersey
(Ahmad et al., 1986). Resistance to billbugs in these trials was primarily associated with the
presence of the Acremonium endophyte. However, evidence of a limited level of genetic resistance

was apparent in selected ryegrasses. As a result, optimum billbug resistance would seem to require
at least a moderate level of genetic-mediated resistance enhanced by an effective endophyte.

     Endophyte-enhanced resistance to chinch bugs has been observed in New Jersey turf trials
of perennial ryegrass, hard fescue, and Chewings fescue (Funk et al., 1985; Saha et al., 1987). At
least two factors appear to be involved; (1) an intrinsic resistance to the chinch bug enhanced by
various Acremonium endophytes, and (2) a less favorable environment for chinch bug development
resulting from  a  healthier  denser  turf.  This second  factor may  either be  the result  of
endophyte-enhanced stress tolerance or from less damage caused by billbugs and other insects
in high endophyte turfs.

                               STRESS TOLERANCE

     Funk et al. (1985) reported striking differences in persistence, recovery from summer stress,
and ability to resist weed invasion during the early fall of 1983 in perennial ryegrass and tall fescue
turf trials conducted in North Brunswick, New Jersey. These tests, seeded in  1976, were irrigated
and maintained at moderately high fertility with frequent close mowing  (2-cm) until June 1981. At
that time, the mowing  height was  raised to 5-cm, irrigation  and weed control  treatments were
discontinued, and fertility applications drastically reduced. A substantial  amount  of crabgrass
(Digitaria spp.) invaded the test  by midsummer 1982 and produced an almost complete ground
cover on the ryegrass trial. The tall fescue test also sustained moderate  crabgrass invasion during
this period.

     By 1983, most perennial ryegrass entries exhibited 95 to 100 percent turf loss and were almost
completely replaced by crabgrass and other weeds. However, several entries persisted with over
90  percent ryegrass turf cover. Indications of maternal inheritance of this dramatically improved
persistence and resistance to weed invasion suggested that turfgrass endophytes were involved.
It was later confirmed, through laboratory analysis, that 98 percent of all ryegrass tillers sampled
from surviving plots contained the Acremonium endophyte. Unfortunately, remnant seed from this
test had been discarded making it impossible to assess endophyte levels in the ryegrasses that
failed to survive. However, since all 15 surviving ryegrasses were highly infected with  endophyte,
it seems unlikely that progenies  free  of endophyte could  have survived. On the other hand, it is
possible that some progenies with endophyte did not survive.
     Optimum performance may well require  a combination  of non-endophytic sources of pest
resistance and/or stress tolerance enhanced by an effective endophyte. It would seem likely that
endophytes vary as much as other biological organisms in their ability to enhance pest resistance,
stress tolerance, and plant persistence. Good performance may also require a high frequency of
endophyte-infected plants within a cultivar.
     Endophyte-enhanced performance was also strikingly apparent in the  adjacent trial of tall
fescue cultivars and single plant  progenies(Funk et al., 1985). The 32 single-plant progenies that
had the best performance contained an average of 98 percent infected tillers. Progenies exhibiting
poor fall recovery and extensive weed invasion  contained  an average of only eight  percent
endophyte-infected  tillers.  This strongly suggests that the dramatic differences in persistence,
resistance  to crabgrass invasion, and  recovery  from summer stress  of the tall fescues were
associated with the presence of an Acremonium endophyte.
     Enhanced  resistance to sod  webworms,  billbugs  and perhaps  other insect  pests  was
undoubtedly a contributing factor in the survival of the  endophyte-containing perennial  ryegrasses
in this test. In another turf trial  at Adelphia, NJ, many of the endophyte-free turf-type  ryegrasses

were able to completely recover from prolonged defoliation by sod webworms. However, in this trial
crabgrass was not present. The severe crabgrass competition at North Brunswick undoubtedly
reduced the recovery  of plants weakened by insects and environmental stress. It is likely that
endophytes did more than just enhance insect resistance to produce the observed response. Insect
populations and apparent insect damage  did  not  appear sufficient to account for the  great
differences observed. Either the insects escaped our attention, or the improved performance and
persistence of endophyte-infected ryegrasses and tall fescues were associated with physiological
factors related to improved stress tolerance and competitive ability.

     It has been our  experience  that endophytes  appear to have  little if any  effect on turf
performance when conditions are favorable. The endophyte-free ryegrasses Tara' and 'Gator1 have
performed well in a four year national testing program and have an excellent reputation in the
turfgrass industry.  Observations of endophyte-enhanced  performance have  normally occurred
under conditions of severe stress or attacks by some, but not all, insect pests. Thus turfgrass
endophytes may be similar to insurance, of little value when everything is favorable but of great
value under certain conditions of biological and/or environmental stress. It also appears that the
favorable effects of endophytes occur more frequently and are more significant in perennial ryegrass
than in tall fescue, at least under field conditions in New Jersey.
     Field studies  near Dallas, Texas (Read  and Camp,  1986) demonstrated  that endophyte-
enhanced performance is common in tall fescue  pastures growing ir+^an area with significantly
higher summer temperatures than  in most other areas of tall fescue usage.  Endophyte-free tall
fescue pastures and lawns have generally performed well in limited short term studies in New
Jersey, Kentucky and Alabama. Although tall fescue is noted for its good overall insect resistance,
deep root system and good heat and drought tolerance, there is some concern that the increased
use of endophyte-free cultivars  may result  in  greater pest problems. Moreover,  previously
unimportant insect and nematode species may be able to increase and thrive on endophyte-free
grass. Loss of stress tolerance and persistence could also occur in especially stressful environments
and in long-term plantings.

     Fortunately, a number of stress physiologists, ecologists, botanists, and agronomists are now
studying  the  role of endophytes in grasses of economic  importance. Controlled studies have
demonstrated that Acremonium endophytes in perennial ryegrass and tall fescue can increase plant
yield and vigor (Clay, 1987; Latch et al., 1985), enhance root growth (Ellis, 1987), and modify water
relations (Ellis, 1987; White and Comeau, 1987). However, this situation is very complex and is not
fully understood  at present. Interactions between host plant genotype, biotype of the endophytic
fungus, plant nutrition,  drought stress, and temperature are commonly detected in these studies.
     The possible role of endophytic fungi in enhancing disease resistance also needs to be studied.
Research has shown that many biotypes of Acremonium endophytes isolated from tall fescue and
perennial ryegrass will  inhibit the growth of a number of plant disease-inducing fungi in vitro(White
and Cole, 1985; Bayaa et al., 1987). However, this has yet to be demonstrated in the field.

     Turfgrass breeders are  currently  using  traditional  plant breeding procedures  including
backcrossing,  recurrent  selection, and  other population  improvement methods to incorporate
desirable endophytes into existing cultivars and elite breeding populations. This germ plasm is being
used to develop  new  cultivars  with  both endophyte-enhanced  performance  and genetic

improvements in turf quality, pest resistance and stress tolerance. Increased knowledge of turfgrass
endophytes is making breeding and evaluation programs much more efficient.

     Large amounts of time and money were wasted in past breeding and evaluation programs as
efforts made to improve and evaluate  animal performance, pest resistance, and stress tolerance
were confounded by the unrecognized effects of endophytic fungi. As a result, our most efficient
approach to long-term cultivar development may well be to (1) remove endophytes from existing
breeding populations, (2) select for genetic improvements in insect resistance, stress tolerance,
etc., and (3)  then incorporate the best available endophyte to enhance performance  wherever
appropriate. Concurrent with the plant breeding efforts, biologists should identify and/or develop
endophytes tailored to  specific host populations and  uses.  Recent and anticipated advances in
molecular genetics may prove to be useful in endophyte selection and improvement programs.

     Perennial Ryegrass

     Tremendous progress has been made in the genetic improvement of perennial ryegrass for
turf usage during the past quarter century. Each  cycle  of breeding has resulted in a stream of new
cultivars with better stress tolerance, increased resistance to many of the most important diseases,
a lower growth profile, and a more attractive appearance.  Useful Acremonium endophytes are
currently being incorporated into an increasing percentage of new perennial ryegrass releases. An
estimated 10 million pounds of turf-type perennial ryegrass seed containing a high percentage of
endophyte was harvested  in  1987.  Perennial ryegrass cultivars containing at least  70 percent
Acremonium endophytes in some seed lots include: 'Regal', 'Pennant', 'Airstar', 'Repell', 'Omega
II', 'Citation II', 'Dasher II', 'Sunrye 246', 'SR-4000', and 'SR-4100'. Additional perennial ryegrasses
with high endophyte levels will be available after the 1988 seed harvest. They will include 'Pinnacle',
'Commander', 'Sherwood', and 'Dandy'.

     Turfgrass managers desiring the benefits of endophyte-enhanced performance must be careful
in their selection of seed. Endophyte viability declines during seed storage, especially under hot,
humid conditions. Therefore, seed harvested in June or July should maintain a high level of viable
endophyte as long as it is stored under cool dry conditions and used before or during the following
spring. At present, seedlings produced from a grow-out test must be examined to determine the
viability of the endophyte. This can be done through  either  microscopic examination of properly
stained plant tissues or by an ELISA test conducted  by a  well-trained laboratory technician. A
number of states are currently offering this service. A dated seed  label showing  percent viable
endophyte would also be useful.

     It is also important to recognize that different seed lots of the same cultivar may vary in initial
endophyte concentrations. For example, in a few of the older  cultivars some seed production fields
were established with old seed containing non-viable endophyte. When this occurred the benefits
of endophyte-enhanced performance were lost.

     Normal fungicide applications made to established turfs usually have little or no effect in
reducing the level of endophyte.

     Hard Fescues

     Hard fescues are receiving increased attention  in the turfgrass industry. Improved cultivars of
this valuable species can produce a dense, disease resistant, attractive and fine-textured turf on
poor soils with little or no supplemental fertilization or irrigation. The greatest weakness of hard
fescues, however, may be their slow recovery from excessive wear or insect damage. Acremonium
endophytes have been identified which enhance both summer performance and resistance to chinch
bugs (Saha et al., 1987). Turfgrass breeders are  currently utilizing these useful endophytes in their

cultivar  improvement  programs. To  date  commercial seed production  has been initiated  on
'SR-3000', a hard fescue with a high level of endophyte.

     Chewings Fescues

     Turfgrass breeders in Europe and the United States have developed a number of attractive
turf-type cultivars of Chewings fescue. They are especially useful for medium-to-low maintenance
turfs, in moderate shade and in regions with cool summer climates. Useful Acremonium endophytes
have been identified in Chewings fescue which can enhance summer stress tolerance and increase
resistance to chinch bugs (Saha et al., 1987). Turfgrass breeding programs at Seed Research of
Oregon, Pure-Seed Testing, Pickseed West, E. F. Burlingham, Rutgers University and the University
of Rhode Island  are attempting to develop improved cultivars of Chewings fescue with high levels
of useful endophytes.

     Other Fine Fescues

     Acremonium-type endophytes  have been discovered in strong creeping red fescue (E. rubra
L. subsp.  rubra). blue fescues (FL  glauca  Lam.), and sheeps fescue  (R ovina  L) (Saha et al.,
1987). Studies are currently underway to assess  their usefulness in enhancing insect resistance
and turfgrass performance. Current  sources of endophyte in strong creeping red fescue have failed
to produce peramine, a toxin shown to be responsible for insect resistance, and have reacted
negatively (less  than or equal to 10% dead) to an aphid bioassay test (Siegel et sL Chapter 16).
Acremonium endophytes in perennial ryegrass, Chewings fescue and hard fescue, however, have
been shown  to produce this compound and have given positive results on the aphid bioassay.
Breeders are currently looking for  endophytes in strong creeping red fescue that will produce
peramine and thus enhance insect resistance. It  would also be of interest to determine whether
non-peramine producing endophytes  have other  mechanisms that might enhance  resistance to
insects and stimulate turfgrass performance.

     Tall Fescue

     Tall fescue  has been widely used for pasture, conservation and turf purposes during the past
four decades, with Kentucky 31 the primary  cultivar grown. Significant genetic improvements in
color, texture, and disease  resistance during this  time led to the development of  many improved
turf-type tall fescues. These cultivars are rapidly increasing in popularity in many parts of the United
States and southern Europe. Many, including  'Adventure', 'Apache', 'Mustang', and 'Rebel II', have
characteristics that could also make them very useful pasture grasses in various regions. However,
only seed lots completely free of viable endophyte should be used for forage establishment in order
to avoid livestock toxicoses.

     Selected Acremonium endophytes would undoubtedly be useful in enhancing turf performance,
insect resistance and  stress tolerance of turf-type  tall fescues, especially  in  highly stressful
environments and low maintenance turfs. However, to date, seed companies and plant breeders
have been somewhat reluctant to develop tall fescue cultivars with high levels of endophyte since
there is  always the possibility that they might be used for pasture establishment. This is especially
likely to occur with poorer quality seed that fails to meet certification  standards.  Therefore, until
appropriate seed labeling and  educational  programs are  in place, breeding for high endophyte-
containing  turf-type  tall  fescues  is likely  to  be delayed.  Current progress in developing
lower-growing, "dwarf-type"tall fescues may encourage breeders to incorporate useful endophytes
since such premium turfgrasses would be less likely to be used for non-turf purposes.

    Kentucky Bluegrass

    Kentucky bluegrass (Poa pratensis L.) is often  considered the Cadillac of lawn grasses in
temperate climates of North America. It is hardy, attractive and widely adapted. The development
of lower-growing, turf-type cultivars with good resistance to the Helminthosporium leaf spot and
melting-out disease has made Kentucky bluegrass even more useful as a turfgrass in humid regions.
Moderate  levels of genetic resistance to billbugs, sod webworms, greenbug aphids (Schizaphis
graminum Rondani) and chinch bugs have been identified in Kentucky bluegrass.

    Endophyte  enhancement of this genetic insect  resistance would be very useful; however,
attempts to find a non-choke-inducing endophyte in Kentucky bluegrass have been unsuccessful
to date. Likewise, there are no reports of a successful inoculation of an Acremonium endophyte
from other genera  of grasses into  this valuable turfgrass species.  Even  if inoculation were
accomplished, it is questionable whether the intergeneric transfer of  an endophyte would be
successful in enhancing insect resistance and stress tolerance. Endophyte-host interactions are
likely to be very specific as  a result  of a long period of coevolution  into a mutually beneficial
relationship (Clay, 1988). If this is the situation, then additional efforts should be made to find useful
endophytes in Kentucky bluegrass and other closely related species of Poa. Successful inoculation
of such endophytes into leading cultivars of Kentucky bluegrass may well prove to be very beneficial.
Because of apomictic reproduction and high levels of heterozygosity present in all elite cultivars of
Kentucky bluegrass,  inoculation techniques will be of greater immediate value than the transfer of
endophytes through hybridization techniques.

    Most elite Kentucky bluegrass cultivars originated as the progeny of a single, highly apomictic
plant. This results in essentially all plants of a given cultivar being genetically identical to each other
as well as to the original parental plant. Successful inoculation of only one plant would, therefore,
be sufficient to incorporate a  useful endophyte into such a Kentucky bluegrass cultivar. Because
of the highly heterozygous genotype in Kentucky bluegrasses, the backcross technique cannot be
used to transfer endophytes or genetic characters into a given cultivar. Hybridization and a modified
backcross technique could  be used, however, to generate highly heterogeneous  and highly
heterozygous populations of Kentucky bluegrasses containing useful endophytes. Elite, new and
unique,  and highly apomictic  cultivars containing useful endophytes could eventually be selected
from such populations.

    Endophytes in Other Grasses

    Endophytes are also being discovered in many other grasses  used for turf and conservation.
White (1987)  examined over 800 herbarium specimens in  93 genera of grasses  and found
endophytic fungi present in 43 grass species in the following 11 genera: Agrostis. Bromus. Cinna.
Elymus. Festuca. Lolium. Melica. Poa. Sitanion and Stipa. These grasses were collected from Africa,
Argentina, Canada,  Europe,  India, Mexico,  New  Zealand and the United States. Many of the
endophyte-containing grasses examined were species "native"to  the continental United States.
Additional  work is needed on the possible significance  of endophytes in these other grass species.

    In conclusion, utilizing endophytes to enhance the performance, insect resistance and stress
tolerance of turf and conservation grasses has considerable potential, and is highly compatible with
goals for reduced pesticide usage. Moreover, an increasing awareness of the role of endophytes
is making  cultivar evaluation and  genetic improvement  programs much more efficient. As our
knowledge of endophytic fungi expands, including a better understanding of their genetic diversity
and how they interact with both plants and the environment, they will become even more useful to
the turfgrass breeder and ultimately to all who enjoy and benefit from improved grasses.

1.    R. A. Prestidge, R. P. Pottinger, and G. M. Barker. 1982. An association of Lolium endophyte with ryegrass resistance
        to Argentine stem weevil. Proc. N.Z. Weed and Pest Control Conf. 35:119-122.

2.    C. W. Bacon. 1988. (Chapter 17).

3.    A. V. Stewart. 1986. The effect of endophyte on perennial ryegrass turf performance. Rutgers Turfgrass Proceedings

4.    A. V. Stewart. 1987.  Plant breeding aspects of ryegrasses (Lolium  spp.) infected with endophytic fungi. Ph.D.
        dissertation, Lincoln College, Univ. College of Agric., Canterbury, N. Z.

5.    A. V. Stewart.  1985. Perennial ryegrass seedling  resistance to Argentine stem weevil.  N.Z.  J. of Agric. Res.

6.    C. R. Funk, P. M. Halisky, M. C. Johnson,  M. R. Siegel, A. V. Stewart, S. Ahmad, R. H. Hurley, and I. C. Harvey.
         1983. An endophytic fungus and resistance to sod webworms: Association in Lolium perenne L Bio/Technology

7.   S. Ahmad,  J. M. Johnson-Cicalese, W.  K. Dickson, and C. R. Funk. 1986. Endophyte-enhanced  resistance  in
         perennial ryegrass to the bluegrass billbug Sphenophorus parvulus. Entomol. Exp. Appl. 41:3-10.

8.   C. R. Funk, P.M. Halisky, S. Ahmad, and R.  H. Hurley. 1985. How  endophytes modify turfgrass performance and
         response to insect pests in turfgrass breeding and evaluation trials, p. I37-I45 in: F. Lemaire, ed., Proc. 5th Int.
         Turf Res. Conf., Avignon, France.

9.   D. C. Saha, J. M. Johnson-Cicalese, P. M. Halisky, M. I. Van Heemstra, and C. R. Funk.  1987. Occurrence and
         significance of endophytic fungi in the fine fescues. Plant Disease 71:1021-1024.

10.   J. C. Read, and B. J. Camp. 1986. The effect of the fungal endophyte Acremonium coenophialum in tall fescue
         on animal performance, toxicrty,  and stand maintenance. Agron. J. 78:848-50.

11.   K.  Clay. 1987. Effects of fungal  endophytes on the seed and seedling biology of Lolium perenne and Festuca
         arundinacea. Oecologia 73:358-362.

12.   G. C. M. Latch, W. F. Hunt, and D.  R. Musgrave. 1985. Endophytic fungi affect growth of perennial ryegrass. N. Z.
         J. Agric. Res. 28:165-68.

13.   D.  Ellis. 1987. Effect of Acremonium lolii infection on water relations in perennial ryegrass. Masters Thesis, Rutgers
         Univ., New Brunswick, NJ. 173 pp.

14.   R.  H. White and M. Comeau. 1987. Tall fescue leaf gas exchange and water relations as influenced by endophytic
         fungi. Agronomy Abstracts, p.  140.

15.   J. F. White, Jr.  and G. T. Cole. 1985. Endophyte- host associations in forage grasses.  III. in vitro inhibition of fungi
         by Acremonium coenophialum. Mycologia 77:487-489.

16.   B.  O. Bayaa, P. M. Halisky and J.  F. White, Jr. 1987. Inhibitory interactions between Acremonium spp. and the
         mycoflora from seeds of Festuca and Lolium. Phytopath. 77:II5.

17.   M.  R. Siegel. 1988. (Chapter 16).

18.   K.  Clay.  1988. Fungal endophytes  of grasses: A defensive mutualism  between  plants and fungi. Ecology

19.   J. F. White, Jr.  1987. Biological and taxonomic  studies on Acremonium section Albo-Lanosa. Ph. D. dissertation,
        Univ. of Texas, Austin.

 State of the Art Research on
Use of Entomophilic Nematodes
for Control of Turfgrass Insects


                    FIELD EFFECTIVENESS OF
                        NEOAPLECTANA AND
                                 Ramon Georgls
                             1057 East Meadow Circle
                               Palo Alto, CA 94303
                               George O. Poinar, Jr.
                       Department of Entomological Sciences
                              University of California
                               Berkeley, CA 94720

    High levels of pest resistance to conventional pesticides together with growing public concern
about potential health and environmental hazards associated with chemical pesticides, are forcing
the industry and public to seek less toxic pest management methods. Entomophilic nematodes of
the genera Neoaplectana (=Steinernema) (Family: Steinernematidae) and Heterorhabditis (Family:
Heterorhabditidae) are regarded as having excellent potential as biological control agents (Kaya
19S5, Poinar 1986). The broad host range and high virulence of these nematodes make them
attractive  candidates for industrial development. Extensive  testing has demonstrated a lack of
mammalian pathogenicity, and the U.S. Environmental Protection Agency has subsequently
exempted these nematodes and their associated bacteria Xenorhabdus from registration and
regulation  requirements.  There  are  a number of described species of Neoaplectana  and
Heterorhabditis (Poinar 1979, 1986, 1987), however, to date, most studies have been conducted
with WL carpocapsae (SL feltiae) and K heliothidis.


    The ensheathed third-stage juvenile of R carpocapsae and it heliothidis (approximately 500u
long and 20u wide) is the invasive form which locates new hosts, initiates infection and is the only
stage in the nematode's life cycle that occurs outside the host in the soil. Besides persisting in the
soil environment without taking in nourishment, the infective stage searches for insect hosts using
sensory organs that are capable of detecting insect excretory products, temperature gradients and
carbon  dioxide  (See Kaya 1985). These/ nematodes  are characterized by their mutualistic
association with bacteria in the genus Xenorhabdus (Poinar 1979, 1986). The infective juveniles
enter the hosts via natural body openings (mouth/' anus or spiracles), exsheath and penetrate

mechanically into the hemocoel (Poinar 1979). Heterorhabditids can also enter directly through the
host's cuticle (Bedding & Molyneux 1982). The infectives liberate the bacteria causing septicemic
death of the host 24-48 hours later. The nematodes feed on the multiplying bacteria and the dead
host tissues, passing through several generations in which their numbers increase tremendously.
Eventually, ensheathed  infectives, carrying the mutualistic bacteria in their gut, emerge from the
depleted insect cadaver. Depending on the temperature the complete life cycle in most insects takes
10-20 days.

                                  FIELD EFFICACY

     Above-ground applications:  In general, attempts to control foliar insects with JSL carpocapsae
have been discouraging, with low host mortality, insignificant population reduction, or inadequate
crop protection (Kaya 1985). Poor control has been attributed to the failure of the nematodes to
survive drying  of the spray deposit. Recent developments in inducing infective nematodes to enter
anhydrobiosis  (Table  4) may increase the  survival of  nematodes and  subsequently  achieve
successful control (Georgis 1987, Ishibashi et al 1987b, Wojcik & Georgis 1987).  Other factors
limiting the use of nematodes on foliage are solar radiation (Gaugler & Boush 1978) and temperature
extremes (Schmiege 1963). The most successful use of nematodes has been against insects which
spend part of their life cycle in protected habitats avoiding harsh environmental exposure. Insects
such as wood borers in the family Sesiidae (Deseo 1986), the artichoke  plume moth, Piatyptilia
carduidactyla  (Bari & Kaya 1984),  and beet armyworm, Spodoptera exigua in chrysanthemum
production beds (Begley 1987), were successfully controlled with these nematodes.
     Soil applications:   Soil inhabiting insects are a logical target for control by these nematodes.
The nematode naturally occurs in moist cryptic environments, especially soil. In the soil they have
advantages over pesticides and microbial pathogens by virtue of their attraction and mobility towards
an insect host. Field applications of hL carpocapsae and HL heliothidis with conventional sprayers
frequently have shown that infective nematodes possess high efficacy for controlling a wide  range
of insects that affect man, such as  imported fire ants (Poole 1976; Quattlebaum 1980),  turfgrass
(Table 1), vegetables (Table 2), ornamentals, shrubs, flowers and caneberries (Table 3). In  many
situations,  the efficacy of the nematodes will depend on their persistence in the soil. Nematodes
introduced into the soil are capable of remaining infective for weeks or even months (Harlan et al
1971,  Miller 1987, Georgis & Hague 1988),  more than  sufficient time to find a host and cause
mortality; but in some situations persistence may be adversely affected by lack of moisture, extreme
temperatures,  soil texture and natural enemies (Molyneux & Bedding 1984, Ishibashi & Kondo 1987,
Ishibashi et al 1987a). Infectivity of nematodes is mostly influenced by soil texture (Georgis & Poinar
1983a, Molyneux & Bedding 1984), temperature (Molyneux 1984, Simons & Van der Schaaf 1986),
and  moisture (Molyneux & Bedding  1984, Kondo & Ishibashi 1985). Differences in field efficacy
exist between  neoaplectanid and heterorhabditid nematodes and their various species and strains
(Tables 1,  3).  For example, heterorhabditids are highly effective against Japanese beetles and
billbugs (Table 1), but provide extremely poor results when mole crickets are challenged. In contrast,
J^L carpocapsae  are effective against mole crickets  but provide only modest control of Japanese
beetles. Differences  in  field  efficacy in part may be related  to the vertical distribution of the
nematodes in the soil after application. N. carpocapsae seem to show a preference for soil near the
surface (Moyle & Kaya 1981, Georgis & Poinar 1983a), and therefore may be best adapted to attack
insects like mole crickets and cutworms which feed at the soil litter interface or on the soil surface.
Heterorhabditids have a greater tendency to move downwards (Georgis & Poinar 1983b) and has


superior host seeking abilities (Gaugler & Campbell, in press), making them efficacious against
Japanese beetles, billbugs and root weevils which are present at the root zones of their host plants.

                        APPLICATION CONSIDERATIONS

     For successful  application  of  nematodes,  the  following   steps  should be  taken  into
1.  Nematodes should be applied to moist soil. Pre and post-application irrigation and moderate
    soil moisture are essential for the movement and persistence of these nematodes. According
    to Poinar (1986), most nematodes applied to dry soil will perish; however, if they are applied
    to damp soil which later becomes dry, many will survive for some period because of their ability
    to withstand gradual desiccation.  Field applications of nematodes to dry turf with 0.64 cm
    pre-treatment irrigation followed by 0.64 cm  post-treatment irrigation  with  normal  rainfall
    resulted in Japanese beetle grub control comparable to a standard insecticide (Shetlar 1987).
    Non-irrigated  turf showed  less control. Nematodes are less  effective in soils close to the
    saturation point (very wet) (Molyneux & Bedding 1984).
2.  Soil  temperature between  18-309C is adequate for nematode survival,  movement and host
    infection. Temperatures above 30QC and below 18gC (Tables 1, 3) may reduce nematode
    effectiveness  (Schmiege 1963,  Molyneux 1984). For effective field control at temperatures
    below 18QC, cold-active strains of N. carpocapsae such as the Umea strain (Pye 1987)  or the
    HL81 isolate of Heterorhabditis sp (Simons & Van der Schaaf 1986) are required.
3.  To avoid the  effects of solar radiation (Gaugler & Boush 1979)  and temperature extremes
    (Schmiege  1963), application in the early morning or early evening is recommended.
4.  Concentrations exceeding 2.5 billion nematodes/hectare (1 billion/acre) are needed to ensure
    that a sufficient population will come into contact with the insect to provide consistent pest
    control. A high concentration is needed to overcome the impact of soil environment, pathogens,
    predators and other factors that can form an ecological barrier to nematode effectiveness. High
    concentrations are required against certain insects such as root maggots which only remain
    for a few days in the soil  before tunneling in  roots (Table 2) or those which are not  highly
    susceptible to nematode infection (Tables 2, 3) because of their small size (i.e., early immature
    stages of mole crickets, root maggots and root weevils).
5.  The spray volume needed depends upon characteristics of the turfgrass  or soil being treated.
    In order to penetrate the deeper thatch (thatch is a tightly bound layer of dead and living roots
    and stems  that accumulates between the soil surface and green vegetation in turfgrass), or
    denser turfgrass  a high spray volume may be needed to incorporate nematodes to the  depth
    frequented  by the target insect. Under these conditions, 4 to 5 gailons/1,000 ft2 (0.2 liters/m2)
    is usually acceptable. It is well known that both moisture and pore size influence the movement
    of soil nematodes (Wallace, 1963). A nematode cannot move between soil particles when the
    pore diameter is  less than the width of the nematode. Although Mi carpocapsae can migrate
    through clay soil, movement will be much less than in sand and sandy loam (Georgis & Poinar
    1983a).  In most field tests, 150 gallons/acre (230 liters/hectare) appears to be adequate, but
    research is  needed to determine  the proper spray volume in relation to the soil type and  insect
    activity at the application site.

6.  When nematodes are applied against root-feeding insects such as white grubs, mole crickets,
    billbugs, and root weevils, it may take 10-30 days before the insect population is significantly
    reduced (Shetlar 1987, Cobb &  Georgis, in press); but against lepidopterous larvae such as
    cutworms and sod webworms, which can be found on or close to the soil or turf surface, control
    can be achieve 2-5 days after treatment (Lossbroek & Theuissen 1985, Shetlar 1987).
7.  More than one application of nematodes may be required  for acceptable control when soil
    environments are not adequate for nematode persistence. Repeat applications may be needed
    against insects that feed over a two-month period (i.e., root weevils and mole crickets), and
    against insects with more than one generation/year (i.e., root maggots).
8.  Nematodes can  often  be applied with the  same  equipment used  for the  application of
    conventional pesticides. Neoaplectanids can withstand application pressures up to  300 psi.
    Accordingly, nematodes have been  applied with small pressurized sprayers, mist  blowers,
    electrostatic sprayers and  helicopters (Kaya, 1985). The infective stages are resistant to shear
    but cannot easily pass through a screen with openings less than 50u in diameter. Also, some
    pumping equipment produces a considerable amount of heat, and should the temperature rise
    above  32QC, the nematodes could be damaged (Poinar 1986).

                         APPLICATION METHODOLOGY

     As with chemical insecticides, soil surface  spraying of nematodes is the method most often
used in response to insect attack. The broadcast approach is quick, easy, and gives good coverage,
but in most cases high concentrations are needed to ensure that  sufficient numbers of nematodes
will come close to the active site of the insect. In some situations nematodes were found to have
potential when applied at planting time (Georgis et al 1983, Pye & Pye 1986, Bari unpublished);
but in certain soil environments that require nematode persistence 4-6 weeks before the appearance
of the target insect stage, (i.e., corn  rootworm, Diabrotica spp and crucifer flea beetle, Phyllotreta
crucjferae), insect damage was not prevented (Munson & Helms 1970, Morris 1987), probably due
to inadequate soil moisture and the non-susceptible nature of  some early larval stages. Other
methods of delivering nematodes to the soil are by means of injection (Glaser, & Farrell 1935), baits
(Georgis et al. 1989)  and alginate capsules (Kaya & Nelson, 1985). Practical implementation of
these techniques will require further  investigation. It is expected  that these  application strategies
will require fewer nematodes for effective control and will provide better protection for nematodes
from extreme environments. Nematodes may also be applied by drip irrigation (Reed et al 1986),
and overhead sprinkler systems (Kaya 1985). Further research may establish these techniques as
practical for nematode applications. Against wood-boring insects, neoaplectanids and heterorhabditids
have been  delivered into galleries with a syringe, cotton swab plug, oil can, and back pack sprayer
(Deseo 1986). Application of nematodes to nylon pack cloth bands lined with pellon fleece or terry
cloth and placed around tree trunks are control tactics used for the control of late stage gypsy moth
larvae Lymantria dispar (Reardon et al 1986), or for overwintering codling moth prepupae Cydia
pomonella  (Kaya et al 1984). Such tactics may  be useful if nematodes are to be used in concert
with other control  measures. Preliminary  investigations have suggested that certain formulations
provide an efficient delivery system, and these results should provide an impetus to attempt control
programs against  insects that  were previously thought to be difficult or impractical to control with
these nematodes (Table 4).


    Neoaplectana and Heterorhabditis  nematodes  have  emerged as  the  only alternative
candidates to chemical insecticides for the control of a wide host range of soil-inhabiting insects.
While the efficacy of the nematode can be affected by undesirable biotic or abiotic factors, the
potential benefits (safe to vertebrates, reduced insecticide  use, no environmental contamination)
are great. Recent development in the mass production  of nematodes through a liquid fermentation
process, and the  ability to induce anhydrobiosis in nematodes may enable them to be used
economically in the management of insect pests in different habitats (Tables 1 -4). Given our rapidly
developing understanding of nematodes and our increasing ability to manipulate them (e.g., genetic
improvement, application techniques, formulations), it would be surprising if they did not eventually
fill an important role in crop protection.

                                      TABLE 1
    Summary of the field trials with Neoaplectana and Heterorhabditis nematodes against selected
turf grass insects (1984-1987).
       Nematode8:              Number ofb          % Control Reduction
       billion/hectare	tests	range	average

                     Japanese beetles, popillia japonica
       Hh:   2.5-12.5           12               27 - 90        61
       HP88: 2.5-12.5            7               55 -100        76
       Nc:   2.5-12.5            8               18-72        47
       Standard insecticide     16               29 - 98        77

                 Northern masked chafer. Cvclocephala borealis
       Hh:   2.5-12.5            7              12-95         53
       HP88: 2.5-12.5            2              14-74         44
       Nc:   2.5-12.5            5               9-61         43
       Standard insecticide      6              39-99         65

                     June and May beetles. Phvllophaga spp
       Hh:   1.0-12.5             4              48-81         61
       Nc:   2.5-12.5             4              39-62         53
       Standard insecticide      3              35-72         54

                     European chafer, Rhizotrogus maialis
       Hh:   2.5-12.5            2              54-61         57
       HP88: 1.2-12.5            3              56-70         63
       Nc:   1.2-12.5            2              36-52         44
       Standard insecticide      4              36-68         59

                        Mole  crickets, Scapterjscus spp
       Hh:   2.5-12.5            3               3-12           8
       Nc:   2.5-12.5            6              42-73         62
       Standard insecticide      6              52-79         69

                        Black cutworms. Agrotis ipsilon
       Hh:     1.2-5.0            3              56-92         76
       Nc:     2.5-12.5          3              44 -100         84
       Standard insecticide      3              68 -100         89

                        Armyvorms, Pseudaletia unipuncta
       Hh:   2.5-12.5             2              68-95         81
       Nc:   2.5-12.5             2              74 -100         87
       Standard insecticide      2              75 -100         96

                    Bluegrass billbuq, Sphenophorus parvulus
       HP88:   2.5-7.5            4              61-79         77
       Nc:     2.5-7.5            4              55-65         56
       Standard insecticide      3              71-88         84
   a:  Hh  = Heterorhabditisheliothidis. HP88 = Heterorhabditis sp  HP88
      isolate,  Nc  = Neoaplectana carpocapsae All strain.

   b:  Biosys, unpublished reports. Plots were 9-36 sq. meters, 4-5
      replicates,  moderate to high insect  pressure.  Soil  temperature &
      moisture  varied  from 13-27 &  from 16-27% (w/w)  respectively
      throughout the test periods.

                                      TABLE 2
    Summary of Neoaplectana carpocapsae All strain field trials (2.5 billion/hectare) applied at
planting or 2-3 weeks after planting against selected  important soil-inhabiting vegetable insects
Field Efficacy0    Remarks0
     Banded cucumber
     beetle, Diabrotica

     Black cutworm
     Aarotis ipsilon
Fair - moderate
Moderate  - high
Neonate larvae

Time of appli-
cation is very
     Flea beetles
     Epitrix spp
     Root maggots
     Delia spp
     Limonius spp
 tobacco,        Fair - moderate
 sweet potato
 Cabbage,  bean  Fair - moderate
 onion,  turnip
 sugar beet,     Fair - moderate
 sweet potato
                    Neonate  larvae

                    Neonate  larvae
                    unsusceptible -
                    short  exposure
                    between  larvae

                   Larvae  rela-
a: Based on 4-7 tests.  Biosys, unpublished reports. Rows  10-20 M  long,
   4-5 replicates.  Soil temperature ranged between  16-28°C and kept moist
   throughout the test periods.

b:  Low to moderate insect pressure.

c:  Fair: Reduction in plant damage over  control but crop  protection
    inadequate.  Nematodes are probably useful  in  an Integrated Pest
    Management  (IPM) program.
    Moderate:  50-80% crop protection.  Useful  in  an IPM program if
               complete protection is mandatory.
    High:  Over 80% crop protection.
d:  Unsusceptible insects:
   LD50 above 50 nematodes/larva under laboratory

                                      TABLE 3
    Summary of the trials with Neoaplectana and Heterorhabditis against important soil-inhabiting
insects of ornamentals, shrubs, flowers and caneberries (1985-1987)a
   potted plants
   potted plants

   potted plants
   potted plants
                    Black vine weevil. Otiorhvnchus sulcatus
                       Strawberry root weevil,  O. ovatus
Hh, Nc: 50-100/cm2   Moderate - high
                                      Moderate control
                                      obtained when
                                       early stage larvae
                                       (less susceptible
                                       than later stages)
                                       are highly present
                                       in pots.

Hh, Nc: 50-100/cm2   Moderate  -  high   Soil temperatures
Hh, HP88: 300-

 Nc:  300-600/cm2

   Japanese beetles.
                     Moderate  - high
                                        Popillia naponica
                                       above  16 C
Soil temperatures
 Hh, HP88:  90/cm
 Nc: 100-500/cm2
                     Low - moderate
Hh & HP88 were
equivalent to
                      European chafer. Rhizotrogus maialis
 Hh,  HP88:  90/cm
 Nc:  100-500/cm2
Hh & HP88 were
equivalent to
    a:  Based on  4-8 tests.  Biosys, unpublished reports, Stimmann  et  al  1985,
       Klingler  1986, Rutherford et al 1987, Wright et al  1988, Shanks &
       Agudelo-Silva 1987.

    b:  Hh:  H. heliothidis; HP88 = Heterorhabditis sp. HP88  isolate;  Nc: = N_._
       carpocapsae All strain.

    c:  Low = under 50% control; Moderate: 50-80% control;  High:  Above 80%

    d:  Low control was obtained at soil temperatures below 14°C (Rutherford et
       al 1978,  Biosys unpublished reports).

                                 TABLE 4
Recent investigations in applications technology of Neoaplectana carpocapsae
Application Site
Target Insects   Results
mixed with

mixed with
bran bait
 mixed with
 antides iccants
 nematodes in

 Nematodes in
 (slow release

 Nematodes in

 Nematodes on
 moist pads
 in traps
plastic containers
plastic containers
Laboratory, plant
Laboratory/ petri
dish lined with
moist foam
capsules contain-
ing tomato seeds
in soil
Laboratory, petri
dish  (moist
Carpenter ant,
harvest ant,
Western yellow-
jacket (adults)

Black cutworms,
mole crickets,
house crickets,
vagrant grass-
hopper (late
Tomato hornworm, 50- 90%
beet armyworm,   infection
imported cabbage
worm, corn ear-
worms (various
larval stages).
German cock-
roach (male)
insects (e.g.,
corn rootworms,
cabbage maggot
Imported fire
et al,
German cock-
roach (various
stages), house
fly adults
                 of wax
                 moth larvae
                 Adult ants
                 to mounds
                 70 - 100%
Kaya et
al 1987
Renn et
al 1985,


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                        TURFGRASS INSECTS
                      WITH NOTES ON OTHER
                                 David J. Shetlar
                          Research Scientist, Entomology
                          ChemLawn Services Corporation
                            Research and Development
                                 P.O. Box 85-816
                               Columbus, OH 43085
    The lawn care industry grew exponentially in the 20 years prior to 1985-86, with major changes
in usage of equipment, chemicals and personnel. In general, small single owner businesses which
operated out of garages or sheds have yielded to large multi-state corporations. The industry passed
the $2 billion receipt marker in 1985 and has continued to grow. Increasing buy outs, consolidation
of companies, and a slowing of total growth have marked the 1985 to 1987 years.
    Many early programs utilized more fertilizer and pesticides, especially insecticides, than what
was probably needed for quality turf. Applications were usually applied in a dilute liquid form sprayed
over the entire lawn. As research  information  was accumulated, environmental concerns were
expressed, and business competition required cost savings, considerable reductions in chemical
usage and changes  in application have occurred. To maximize profits while satisfying customer
expectations, most lawn care companies now provide complete fertilization, annual grass and
broadleaf weed control and insect  control. Many southern and western markets also require
fungicide usage in order to maintain quality turf.
    Though there had been increasing numbers of activist groups raising concern over lawn care
chemicals, no major  effects were noted until 1985 to 1987. During these years, national  media
began to exploit the sensationalism provided by these environmental activists. Many states have
begun to more actively regulate the industry and the way lawn care is delivered. Many states have
enacted regulations on applicator training and certification, customer right to  now, pre and post
application notification and posting of treated  lawns. Unfortunately, the scientific data base is
inadequate to fully answer the questions raised about long-term chemical exposure, synergistic
effects of chemicals and possible water contamination. Though there is little scientific information
to support claims of damage there is also little information available which has proved that damage
can not occur. This raises the problems of risk and risk assessment. Some people want no risk in
life while others can accept reasonable risks. This dilemma is difficult to resolve with reason.
    Because of perceived changes in customer wants and a desire to provide safe and effective
alternatives to standard lawn care treatments, ChemLawn Services Corporation and its  research
and development staff have been investigating alternative controls and systems for the last five


years. In order for alternatives to be used, they must be easy to use, effective and comparable in
cost. Unfortunately,  the few alternatives available for insect pest control have been, historically,
costly and/or marginally effective.
     Insect parasitic (entomogenous) nematodes have been studied since the 1920's, but they
were difficult and expensive to produce and did not produce lasting effects. From 1929 to 1940, R.
W. Glaser et al. (1940) detected, reared and field tested an entomogenous nematode, Neoaplectana
glaseri Steiner. Possibly because of the war effort and discovery of synthetic organic insecticides,
little work on entomogenous  nematodes for control  of Japanese beetle grubs was subsequently
undertaken. Glaser attempted to produce N. glaseri in large numbers using a veal pulp medium but
this was labor intensive, difficult and did not provide  sufficient nematodes for applications to large
areas. Recent interests in entomogenous nematodes have yielded better culture techniques for N.
carpocapsae Weiser and  Heterorhabditis heliothidis  (Khan, Brooks and Hirschman)  (Dutky et al.
1964, Bedding 1981, Wouts 1981). Recently,  a new venture capital company, Biosys (Palo Alto,
CA), had developed additional improved rearing procedures so that commercial production of these
nematodes (Neoaplectana spp. [=Steinernema] and Heterorhabditis spp.) was possible and field
evaluations could be undertaken. This paper contains information derived from research on these
nematodes as well as some comparative studies with other alternative products such as Bacillus
thuringiensis (Bt) strains.
     The major turfgrass pests include: a)  surface feeding  insects such as  chinch bugs, sod
 webworms, cutworms, armyworms and greenbugs; as well as, b) soil or root feeding insects such
 as white grubs, billbugs and mole crickets. These pests are appropriately discussed by, Niemczyk
 (1981), Baker (1982), Shetlar et al. (1983), and Tashiro (1987).
     The white grubs (Japanese beetle, Popillia japonica Newman; masked chafers, Cyclocephala
 spp; May-June beetles, PhyHophaga spp; European chafer, Rhizotrogus majalis [Razoumowsky];
 Oriental beetle, Anomala orientalis Waterhouse; Asiatic garden beetle, Maladera castanea [Arrow];
 and, green June beetle, Cotinis nitida [L]) are, by far, the most troublesome widespread turfgrass
 pests. The highly mobile  adults seek out quality turf  and lay eggs in the soil. The larvae, white
 grubs, come  to the soil surface to feed on plant  roots and other organic material included in the
 thatch.  Since most turf insecticides are easily bound to the living and dead turf tissue (Niemczyk
 and Krueger 1982; Sears and Chapman 1979; Niemczyk 1987), white grubs are difficult to challenge
 without considerable irrigation following an insecticide spray and reduction of the thatch layer. Even
 when white grub  populations are below damaging levels, mammal predators such as raccoons,
 skunks, opossums and moles can severely damage turf in their search for an arthropod meal.
     Since the Japanese  beetle is one of the most important turf damaging grubs in the eastern
 United States, extensive  research has been undertaken to control this pest using many tactics
 (Fleming 1976). Considerable work on biological controls, especially bacterial milky diseases (Klein
 et al. 1976), has been undertaken for control of  Japanese beetle grubs as reviewed by Fleming
 (1968).  Bacillus popilliae has been proven effective but the lawn care industry has made little use
 of this product. This is probably because of difficulty of application, reliability in cool soils, expense,
 lack of  availability of large quantities of spore powder and  long time of  establishment.  Similar


experience has been met with the other biological controls such as parasitic wasps (Tiphia spp.),
parasitic flies (several Tachinidae), and fungal diseases (Metarrhizium spp. and Beauveria spp.).
Because of these problems with  white  grub  biological controls, we were most interested in
concentrating our nematode research in this area.
     Mole crickets (tawny  mole cricket, Scapteriscus vicinus Scudder; southern mole cricket, &
acletus  Rehn and Hebard; and short wing mole cricket, £L abbreviatus Scudder) are the most
troublesome and damaging turf insects in Florida as well as surrounding southern  states (Walker
et al. 1984). These pests  damage turf by uprooting  plants during tunneling and  direct feeding.
Mature nymphs and adults can easily dig deep into the soil and thus avoid short residual, surface
applied  insecticides. Insecticide laced baits have been used effectively in some cases, but these
baits rapidly decompose or lose their feeding attractiveness  in periods of rainfall. As with  the
Japanese beetle, imported mole crickets have not responded well to control by biologicals. Because
of these problems, we  were interested in the  possibility  of  using parasitic nematodes as an
alternative biological control measure.
     We placed less emphasis on development of entomogenous nematodes for control of surface
insects because surface applied insecticides such as diazinon and chlorpyrifos are  so effective at
low rates.
     Our early research using entomogenous  nematodes was  a multifaceted approach. We
performed laboratory evaluations of nematode species and strains for infectivity against Japanese
beetle and northern masked chafer (CX boreal is Arrow) grubs. At the same time we investigated
irrigation requirements essential to  the establishment of nematodes into soil covered by turfgrass
and evaluated the compatibility of the nematodes with the liquid lawn care system.
                       WHITE GRUB CONTROL STUDIES

 Nematode Strain Evaluations

     There are four species of Neoplectana (=Steinernema) (N. giaseri Steiner. N. bibionis Bovien,
 N. carpocapsae Weiser and N. intermedia Poinar) and numerous recognized strains (Poinar 1986a).
 Several species of Heterorhabditis. including undescribed ones, have been evaluated for insect
 control. The common species are K heiiothidis (Khan, Brooks & Hirschmann), K bacteriophora
 Poinar, and tL spp. "HP88".Biosys was able to collect and maintain cultures of all of these species
 as well as numerous strains.
     In 1983, Keith  Kennedy  (former ChemLawn Services Research  Scientist; now Senior
 Entomologist, S.C. Johnson & Son, Inc.) and his research associate, Jeff Rodencal, performed initial
 evaluations of nematode strains for control of Japanese beetle and northern masked chafer grubs.
 These tests were performed in PVC cylinder micro plots, a technique initially developed by Kennedy.
 The micro plots are 20.5 cm (8-inch) long pieces of 15.3 cm (6-inch) diameter polyvinyl chloride
 (PVC) drain pipe driven into the soil to a depth of 15.3 cm. Each cylinder has a bottom screen which
 allows drainage but prohibits insect escape.  A  15.3 cm golf course cup cutter can be used to take
 turf plugs from established turf. The plugs, consisting of the turf with 8-10 cm of soil, are placed in
 the cylinders. Field collected white grubs, usually third instars, are used to infest each turf plug. In
 most cases, ten white grubs are placed head down into small holes produced by forcing a 8.0 mm


sharpened wooden dowel through the thatch. Any grubs not digging in within 1-3 hours are replaced
with fresh grubs. The grubs are allowed 2-3 days to acclimate before control substances are added
to the cylinders.
     Initial strain evaluations against Japanese beetle grubs are presented in Table 1.  From this
test it appeared that N. carpocapsae 'Breton' and N. glaseri could produce moderate and excellent
control respectively.  A similar study using lower rates of nematodes indicated  a definite  rate
response (Table 2). This was also seen when northern masked chafers were challenged with low
rates of nematodes (Table 3). These three tests indicated that nematodes could control white grubs
if high rates were used.
     In 1984, we continued strain  evaluations but decided that a smaller laboratory screen might
give more consistent  results. Third instar white grubs were placed in 2.5 cm diameter by 10 cm long
plastic vials filled with sterilized potting soil to a depth of 7 cm. Two Japanese beetle grubs or one
northern masked chafer grub was  placed in each vial and treatments (approximately 250 infective
nematodes per vial) were replicated six times. The vials were examined at 2, 4 and 7 days after
treatment (DAT).
     Mortalities at 2,  4 and 7 DAT are presented in Table 4 for Japanese beetle grubs and Table 5
for northern masked chafers. From these studies, it appeared that the northern masked chafer might
be  less susceptible to nematode attack. The K spp. 'HP88' provided adequate mortality for both
grub species. However. N. carpocapsae '42' (='Bretonf x 'DD136') and N. c. 'Breton' produced the
best control of Japanese beetle grubs while R c^ 'Italian' worked best on northern masked chafers.
     This experiment was performed again with larger vials (5.0 cm diameter x 10.0 cm deep) using
four Japanese beetle grubs per vial. The grubs were allowed to acclimate for 48 hours and inactive
grubs were replaced  before the 450 infective nematodes per vial were added. The vials were rated
at 7,  14 and 21  DAT. The mortality data are presented in Table 6. It appeared that JH. heliothidis
'NC' and  K spp. 'HP88' produced the  higher mortality, 76% and 82% respectively, at 21 DAT.
Most of the N,. carpocapsae strains, except for hL a 'Breton x DD136', did not provide reasonable

Application Evaluations

     By 1985, we had decided that entomogenous nematodes should be field tested on small plots
for control of white grubs. We also wanted to know if the nematodes were compatible with  the liquid
lawn care application system and chemicals. Of most concern, was knowing if fertilizers, herbicides
or insecticides would adversely affect the infective juvenile nematodes.
     Nematodes were added to sample tank mixes containing water, water + fertilizer (nitrogen,
phosphorus, potassium), water + fertilizer + broadleaf herbicide, water  + fertilizer + broadleaf
herbicide + insecticide, and water + fertilizer + broadleaf herbicide + preemergence  (crabgrass,
etc.) herbicide. These mixtures were agitated continuously on a shaker tray  and samples were
withdrawn at 1, 2, 3,  5, 8, 12 and 24 hours. By five hours only the preemergence mix had caused
significant nematode  mortality. By 12 hours the fertilizer, fertilizer + broadleaf herbicide and fertilizer
+ broadleaf herbicide + insecticide had mortality no greater than nematodes in water. In fact, the
fertilizer alone  had  significantly less mortality. By  24 hours the insecticide mix had caused
considerable mortality. When nematode infectivity was bioassayed (with wax moth larvae), only the
water, fertilizer and fertilizer + broadleaf herbicide had not caused a significant reduction  by five
hours. The water  or fertilizer  mixes remained  equally benign  at  12 hours. In  summary,  the


nematodes are compatible with liquid fertilizers and commonly used broadleaf herbicides. This was
encouraging because the nematodes would most likely be used when preemergence herbicides
would not be used and supposedly insecticides would not be necessary.

Effect of Irrigation

     Another concern with applying nematodes was their  requirement for establishment into the
turf and soil. Entomogenous nematodes are highly intolerant of environmental extremes, especially
moisture and temperature (Gaugler 1981). Jackson  et al. (1983) greatly increased establishment
of K bacteriophora in pasture soil for white grub  control if applications were made during rain or
followed with irrigation. We wanted to know if irrigation was needed and if so, how much, when the
ChemLawn nozzle was used.  The ChemLawn nozzle, a  low pressure showerhead type which
delivers 0.16 liter/m2 (=4 gal/1000 ft2) is the liquid lawn care standard.

     The previously described PVC microplots were used in a greenhouse. Turf plugs were taken
from a two year old stand of Kentucky bluegrass  grown on Blount silt loam (32% sand, 36% silt,
32% clay) with pH's of 6.5-8.0. Each plug had an average of 0.75 cm of thatch. The greenhouse
was maintained at 20QC (±59C) and the turf was allowed to  acclimate for seven days. The turf was
then given a water drench and allowed to dry to the wilting point (soil moisture = 18.5%). Small holes
were drilled radially around the soil plug at two levels (5 holes at each level of 2.5 cm and  5.0 cm).
Each turf plug was inoculated with approximately 24,000 infective nematodes (=12.35 x 109/ha; =
5.0 x 109/a) in 3.2 ml of water. JSL carpocapsae 'Mexican',  NL glaseri and hL heliothidis 'NC' were
used. Treatments were followed with 0.0, 63.0,126.0 or 252 ml water/cylinder irrigation (=0.0, 0.25,
0.50,1.0 inch). The cylinders were then capped with aluminum foil to reduce evaporation. A greater
wax moth larva (Galleria mellonella L.) was placed in each of the  holes and restrained for 48 hours
at 3,5 and 11 DAT. The larvae were then removed, incubated for  five days, and dissected to check
for nematode infection.
     The data indicated that there were few differences between the nematode species so the data
were pooled for each irrigation amount in each bioassay (Shetlar et al. 1988).  These data are
graphically presented in  Figure  1. From this graph  one can readily see that at least 0.64 cm (=0.25
inch) of irrigation is needed to establish nematodes for up to five  days after treatment.  At least 2.5
cm (=1.0 inch) irrigation is needed to sustain the nematodes to 11 DAT in dry soil.

Small Plot Grub Tests -1985

     On 28 August 85,  two areas with Japanese beetle grubs were selected beside two  fairways
at a country club in central Ohio. The soil (a Blount silt loam) was at the turf wilting point and was
thinly covered by Kentucky bluegrass mixed with small amounts of fine fescue  and crabgrass. hL
carpocapsae 'Mexican' was used because of availability. Each treatment was replicated five times
in each area (A and B) in a randomized complete block design using 6.1 x 6.1 m treatment blocks.
Treatments were: 1) 12.35 x 109 nematodes (nemas)/ha with a ChemLawn nozzle at 0.16 liter/m2
(=4 gal/1000 ft2); 2) 6.18 x 109 nemas/ha with a ChemLawn nozzle; 3) 12.35 x 109 nemas/ha with
an eight pinhole nozzle boom  at 0.16 liter/m2; 4) Isozophos 4E (=Triumph,, Ciba-Geigy Corp.)
Insecticide at 2.24 kg (Al)/ha with a ChemLawn  nozzle; and 5) water treated check (0.16  liter/m2).
Area A was treated 9 September and no irrigation was applied after treatment. Area B was treated
10 September and treatments were irrigated with  about  0.64, cm water  immediately following
application. A trace of rainfall occurred the  night of 9 September but this was not enough to wet the


soil. Area A was evaluated on 2 October, 23 DAT, and Area B was evaluated on 9 October, 29
DAT. Grub populations were assessed by taking four 0.09 m2 (1.0 ft2) samples at random from
each treatment block. Only traces of rainfall had occurred during the experiment and the soil was
very dry (16-18% moisture) at the end of the experiment.
     The data for Area A and Area B are presented in Table 7 (Shetlar et al. 1988).  From these
data it is evident that irrigation increased grub control and possibly increased infection.  However,
good control was not achieved in either area when compared to an insecticide. We felt this was
most likely due to the extremely dry conditions.

Small  Plot Grub Test -1986

     In 1986, we repeated the field test of nematodes using irrigation before and after nematode
applications. We were also able to obtain sufficient quantities of H. heliothidis 'NC1 to be included.
     On 10 September 86, an area with Japanese beetle grubs was treated beside a fairway at a
central Ohio country club. Treatment blocks were 1.2 x  1.5 m and each block was irrigated before
application with 22.7 liter water  (=0.64 cm). Treatments were: 1) 12.35 x 109 nemas/ha of  N.
carpocapsae 'Mexican'; 2) 12.35 x 109 nemas/ha of H. heliothidis 'NC': 3) Isofenphos 21 (=Oftanol,
Mobay Chemical Co.) at 2.24 kg (Al)/ha; and, 4) water treated checks. Treatments were applied in
7.6 liter water from watering cans using shower head nozzles and each block was irrigated after
treatment with 15.1 liter water (=0.64 cm total). Pretreatment grub counts were taken from four
blocks in  the area and posttreatment counts were taken 39 DAT using three 0.09 m2 samples in
each treatment block.
     The  data from this experiment are presented in Table 8 (Shetlar et al. 1988). This field test
demonstrates that adequate grub control (> 70%) can be achieved using entomogenous nematodes
though this control may be significantly  less than using an insecticide. Also indicated is that
Heterorhabditis spp. may be better suited than hL carpocapsae.

Discussion of Use of Nematodes for White Grub Control

     Entomogenous nematodes appear to show promise as a biological control agent to manage
white grubs in turfgrass. The nematodes are compatible with the materials (at least fertilizer) and
equipment used by liquid lawn care applicators. For soil insect control, irrigation and soil moisture
seem to be the most critical factors for success of the nematodes. The nematode species and strains
also exhibit a considerable range of activity. In our tests R heliothides 'NC' and K spp. 'HP88'
appear to be more useful than the N. carpocapsae strains. Unfortunately, N. glaseri, the first species
identified for grub control (Glaser et al. 1940), remains difficult to culture and thus difficult to evaluate.

                      CONTROL OF TURF LEPIDOPTERA

Screening of Nematodes and Other Biologicals

    Surface feeding turf Lepidoptera  such  as sod webworms  (Pyralidae: Crambinae) and  the
armyworm-cutworm (Noctuidae) complexes are periodic pests. Though these are easily controlled
with low rates of insecticides, we are very interested in biological alternatives. The literature indicates
that these pests should be susceptible to entomogenous nematodes (Poinar 1986b) as well as other
biologlcals such as Bacillus thuringiensis  (Bt) (Ignoffo and Gregory 1972;  Krieg and Langenbruch
1981) and Beauveria or Metarhizium (Perron 1981). Since the nematodes were  available and Bt
was commercially marketed, we undertook numerous tests to evaluate the  efficacy of these agents
for caterpillar control.

     In the fall of 1984, an  outbreak of sod webworms (mainly the  tropical sod webworm,
Herpetogramma phaeopteralis Guenee) occurred in the Boynton Beach, Florida area. Larvae were
field collected and shipped to Columbus,  Ohio for testing. The larvae were maintained  on
bermudagrass clippings until they were about 1.0 cm long. In the first test, glass petri dishes (20 x
80 mm) were lined with two pieces of 80 mm diameter fijter paper wetted with 2.0 ml distilled water.
Several leaf blades of bermudagrass  were  added  and dishes were inoculated with about 800
nematodes in 1.0 ml water. Four larvae were placed in each dish and treatments  (N. carpocapsae
'Breton', N. a 'Agriotos1 and water check)  were replicated three times. By 4 DAT most of the larvae
had spun webbed tunnels along  the upper surface  of the petri dishes. Apparently, this behavior
effectively isolated the larvae from the nematodes. Out of 12 larvae per each treatment the following
mortalities were  recorded: two in the checks,  seven in the NL c^ 'Breton' and eight in the NL a
     A second test was established using 5.0 x 10.0 cm snap cap vials filled with  2.5 cm of potting
soil upon which  were placed  six blades  of bermudagrass. Four sod webworms and about 800
nematodes were added and the treatments (NL a 'Breton', NL c^ 'Agriotos', NL c. 'Italian' and water
check) were replicated  five times. The vials were evaluated 3 DAT and the larvae were dissected
to confirm nematode infection. Fewer larvae sheltered themselves above the soil  and the infection
rate is presented in Table  9.
     A petri dish test in 1985 using the  armyworm, Pseudaletia unipuncta  (Haworth), provided
excellent control within seven days. Though all larvae subjected to nematodes had been killed,  the
percent of larvae with active infections was dramatically different. JSL c^ 'Breton' had 100% infection
and N, glaseri had 87% infection but no nematodes were recovered from the hL heliothidis treated
     PVC cylinder micro plots were used  in 1986 and the parasitic nematodes were compared to
commercial preparations of Bt (Thuricide and Javelin, Sandoz, Inc.) and surface insecticides. In  the
first  two evaluations,  armyworms were laboratory reared on  artificial diet  until  they were
approximately 2.0 cm long. Each turf plug was infested with eight larvae and irrigated with 60 ml
water 24 hours before treatment. Each cylinder was covered with a screen top to prohibit armyworm
escape  or predator/parasitoid contamination.  Each treatment  was replicated  five  times  and
evaluations were made 3 DAT  for nematode treatments  and 7 DAT  for Bt and water control
treatments. Chlorpyrifos (Dursban 4E,, Dow Chemical  Co.) was used  as  a standard  surface
insecticide. The results of  these two tests  are presented in Tables 10 and Table 11.

     In the first test, the nematodes gave excellent control and the NL carpocapsae. strains were
not significantly different (P < 0.05, df = 6)than the chlorpyrifos treatment. K heUothidis 'NC' was
evaluated as providing good control (> 70%) though it was significantly lower than the chlorpyrifos
treatment. The Bt treatments did not provide adequate control and all the turf was eaten by the end
of the study.
     The second test was somewhat the same though  K  heliothidis 'NC' provided inadequate
control (< 70%). NL bibionis was also considered inadequate. This may have been caused by the
lower soil moisture. Soil moisture in the first study was 26% by weight while the second study had
only 18% moisture. The Bt treatments, even at 4X rates,  still did not provide control of armyworm
larvae. This is partially due to the large size of the larvae and some soil Lepidoptera seem to be
refractive to Bt toxins.
     Our initial  screenings indicate that entomogenous nematodes appear  to have excellent
 potential for control of turf lepidopterous pests. £L carpocapsae strains seem to be the most active
 nematodes. Tests with commercial Bt preparations indicate that problems exist concerning soil
 Lepidoptera species controlled and timing,  or size of larvae to be controlled.  In other words, Bt
 does not seem to have a broad spectrum of control when compared to entomogenous nematodes.
                           MOLE CRICKET CONTROL
 Field Evaluations
     Preliminary  screening of entomogenous nematodes for  infectivity  to  mole crickets was
performed by Ken Lawrence (Associate Research Scientist, ChemLawn Services R&D, Boynton
Beach, FL) in soil filled cups or petri dishes in 1984. He noted that mole crickets (Scapteriscus
acletus and £L vicinus) could be infected  and  killed though nematode reproduction  was often
     In late 1985, Ken Lawrence and Richard Miller (Entomologist, Biosys, Palo Alto, CA) performed
another bioassay of parasitic nematodes for mole cricket infectivity. £L carpocapsae 'Mexican' and
'All1 and M, bibionis 'SN' were applied to moistened filter paper in 15 x 100 mm plastic petri dishes.
A single adult £L acletus was placed in each petri dish and mortality was recorded at 4 and 6 DAT.
Dead mole crickets were removed and placed on sterile moistened filter paper in fresh dishes for
72-120 hours for incubation. After incubation the insects were dissected to evaluate nematode
reproduction. These  data are presented in Table 12. The higher rates  of NL carpocapsae strains
were able to achieve 100% mortality and nematode reproduction was  more successful than with
N. bibionis.

     In 1985, we undertook a series of field applications of parasitic nematodes to attempt to control
mole crickets. A Boynton Beach, FL golf course driving range was selected. This area was well
populated by mole crickets as evidenced  by numerous  trails and mounds which were easily


assessed in the short cut bermudagrass. Area A consisted of treatment blocks 9.1 x 9.1 m replicated
five times in a randomized complete block design. Area B consisted of large unreplicated treatment
blocks, 15.2 x 24.4 m. Area A was evaluated by counting all the mole cricket tunnels within each
treatment block while Area B was evaluated by counting ail the tunnels in a 9.1 m wide transect
running the length of the blocks. A pretreatment flushing determined that most of the mole crickets
were adults and most (> 70%) were S, vicinus. The nematodes were applied using a ChemLawn
nozzle calibrated at 0.16  liter/m2. Both areas were irrigated through the golf course system the
evening following applications.

     Mole cricket activity was evaluated a week after treatment and the data are presented in Table
13 and Table 14. These data indicate that hL. carpocapsae was effective in reducing adult mole
cricket activity and there  was a definite rate response. Unfortunately,  nematode infected  mole
crickets were not recovered using a soap flush a week after treatment and mole cricket activity
resumed in all plots within four weeks after treatment.
     A summer  application of nematodes was made to  bermudagrass containing  numerous
nymphal mole crickets (1.5-2.5 cm long) using the design of Area A (above). These data are
presented in  Table  15. At  this time no significant control was achieved using  nematodes or

Discussion on Using Parasitic Nematodes for Mole Cricket Control

     Our experiences indicate that entomogenous  nematodes have the ability to attack  mole
crickets. However, there seems to be some problem with  the  nematode's ability to enter  mole
crickets in field conditions. This may be due to the almost constant mole cricket activity or the dense
covering of hydrophobic hairs. We feel  that better control may be achieved if a bait containing
nematodes can be developed.

 Bluegrass Bill bug

     The bluegrass billbug, Sphenophorus parvalus Gyllenhal, is an important pest of cool season
 turf across the northern states (Niemczyk 1983, Tashiro & Personius 1970). This pest is especially
 difficult to control because the adults are highly migratory and are susceptible to surface insecticides
 for a short time during the spring (Niemczyk 1982). Soil insecticides are often effective against the
 larvae when they emerge from turf plants. However, the  larvae may emerge over an extended
     In 1983, a ChemLawn Services branch in Boise, Idaho applied NL carpocapsae 'Breton' to six
 lawns with active billbug larvae. The nematodes were applied at a 7.75 x 108 nemas/ha (= 3.1  x
 108  nemas/a) using the ChemLawn nozzle at 0.16 liter/m2. Mark Mahady (Associate Research
 Scientist, ChemLawn Services Corp., Monterey, CA) supervised the application and subsequent
 sampling. Sampling at 14 and 21 DAT revealed a majority of dead larvae (creamy yellow in color),
 some  moribund  larvae (slow  moving) and few normal larvae.  Dead larvae  were collected  and

shipped to George Poinar, Jr. (Univ. California, Berkeley, CA) for evaluation. Positive nematode
infection was confirmed. By 28 DAT, no live billbug larvae were found on the treated lawns, but by
35 DAT two lawns contained fresh young larvae and displayed new injury. This test indicates that
R carpocapsae is able to infect and control the bluegrass billbug larva.

Crane Flies

     The European crane fly, Tipula paludosa Meigen, or 'leatherjacket' is a northwestern Europe
native which has become established in the Pacific Northwest (British Columbia, Washington and
Oregon) (Jackson and Campbell 1975). This pest can cause considerable damage to turfgrass.
An European test of nematodes for control of the European crane fly indicated that the larvae are
susceptible to infection (Lam and Webster 1972).
     In 1986, Patrice Suleman (Research Associate, ChemLawn Services Corp., Columbus, OH)
located an area of golf course turf with significant damage apparently due to a native (range) crane
fly (Tipula spp.). Larvae were field collected and transported to the laboratory for a petri dish test.
Glass petri dishes (15 x 80 mm) were lined with filter paper and five larvae per dish were distributed.
Each dish received 2.0 ml distilled water and 1.0 ml aliquot containing 200 or 400 nematodes. Four
nematode strains plus a water check were evaluated with three replicates. Mortality was recorded
at 2,4 and 8 DAT and dead larvae were examined for nematode infection. The data for this test are
presented in Table 16. The data indicate  that this crane fly larva  is susceptible to all the strains
     Our present day knowledge of the susceptibility of turfgrass insect pests to entomogenous
 nematodes indicates that this may be the first biological  control agent with a broad spectrum of
 activity. We have laboratory and field data confirming activity against surface insects such as sod
 webworms, cutworms, armyworms and crane fly larvae.  We also have laboratory and field data
 confirming activity against soil insects such as white grubs (Japanese beetles and northern masked
 chafers), mole crickets, and billbug larvae. The only major pest not evaluated  has been chinch
 bugs. This pest is probably too small for successful infection but a trial test should be performed.
 Other sporadic and minor pests not likely to be controlled by parasitic nematodes are greenbug,
 winter grain mite, Bank's grass mite, bermudagrass mite and several scales and mealy bugs.
     Future challenges include:  1) identification of soil conditions most conducive to nematode
 survival and activity; 2) refinement of application techniques (sprays, irrigation, baits, etc.); and 3)
 improved mass production which maintains the nematodes1 hardiness and infectivity while lowering

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Baker, J.R. (ed.) 1982. Insects and other pests associated with turf: Some important, common, and potential pests in the
        southeastern United States. North Carolina Agr. Ext. Serv. AG-268:108pp.

Bedding, R.A. 1981. Low cost in vitro mass production of Neoaplectana and Heterorhabditis species (Nematoda) for field
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Duncan, D.B. 1955.  Multiple range and multiple F tests. Biometrics. 11:1-42.

Dutky, S.R., J.V. Thompson and G.E. Cantwell. 1964. A technique for the mass propagation of the DD-136 nematode.
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Perron, P. 1981. Pest control by the fungi Beauveria and Metarhizium. pp 463-482. In H.D. Surges (ed), Microbial Control
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Fleming, WE. 1968. Biological control of the Japanese beetle. United States Dept. Agr., ARS Tech. Bull. 1383:78pp.

Fleming, W.E. 1976. Integrating control of the Japanese beetle - A historical review. United States Dept. Agr., ARS, Tech.
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Gaugler, R. 1981. The biological control potential of neoaplectanid nematodes. J. Nematol. 13:241-249.

Glaser, R.W., E.E. McCoy and  H.B. Girth. 1940. The biology and economic importance of a nematode parasite of insects.
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Ignoffo, C.M. and B. Gregory. 1972. Effect of Bacillus thuringiensis B-exotoxin on  larval maturation, adult longevity,
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Jackson,  D.M. and R.L.  Campbell. 1975. Biology of the European crane fly, Tipula  paludosa Meigen, in western
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Jackson, T.A., B.W. Todd and WM. Wouts. 1983. The  effect of moisture and method of application on the establishment
         of the entomophagous nematode (Heterorhabditis bacteriophora) in pasture. Proc. 36th  N.Z. Weed & Pest
         Control Conf. pp 195-198.
Klein, M.G., C.H. Johnson and T.L Ladd, Jr. 1976. A bibliography of the milky disease bacteria (Bacillus spp.) associated
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Krieg, A. and G.A. Langenbruch. 1981. Susceptibility of arthropod species to Bacillus thuringiensis. pp 837-896. In H.D.
         Burges (ed.), Microbial Control of Pests and Plant Diseases 1970-80. Academic Press, London.
Lam, A.B.Q. and J.M. Webster. 1972. Effects of DD-136 nematode and of a B-exotoxin preparation of Bacillus thuringiensis
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Niemczyk, H. 1981.  Destructive Turf Insects. HDN Books, Wooster, OH. 48pp.
Niemczyk, H.D. 1982. Chinch bug and bluegrass billbug control with spring applications of chlorpyrifos, pp 85-89. In H.D.
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Niemczyk, H.D.  1983. The bluegrass billbug:  a frequently misdiagnosed pest of turfgrass. Amer. Lawn Appl.,
Niemczyk, H.D. 1987.  The influence of application timing and posttreatment irrigation on the fate and effectiveness of
         isofenphos for control of Japanese beetle (Coleoptera: Scarabaeidae) larvae in turfgrass. J. Econ.  Entomol.
Niemczyk, H.D. and H.R. Krueger.  1982. Binding of insecticides on turfgrass thatch, pp 61-63. In H.D. Niemczyk and
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 Poinar, G.O. 1986a. Recognition of Neoaplectana species (SteinernematidaerRhabditida). Proc. Helminthol. Soc. Wash.
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                               TABLE 1
   Japanese beetle larval control in turfgrass plugs with entomogenous nematodes, Milford
Center, OH.
Treatment Rate X larvae/cylinder % control
(13/V/83) (nemas/ha) 10 DAT
N. c. 'Breton' 14.1xl09
N. c. 'HOP' 14.1X109
N. c. 'Mexican' 14.1xl09
N. g. 14.1X109
H. spp 'HP88' 14.1X109
N. c. = Neoaplectana carpocapsae ; N.
Heterorhabditis .
8.2 a
2 . 5 cd 69
3.8 be 53
7.8 a 4
0.8 d 90
6.0 ab 27
g. = N. alaseri; H. =
      Equivalent to 5.7xl09 nemas/a.

      Ten 3rd  instar larvae per cylinder; N = 6; means followed by
      the same letter are not  significantly different (P = 0.1;
      Duncan's [1955] multiple range test).

      Calculated by Abbott's  (1925)  formula.

                                TABLE 2

    Control of 2nd and 3rd instar Japanese beetle larvae with varying rates of Neoaplectana
carpocapsae and NL glaseri. Milford Center, OH, 1983.
N. carpocapsae
1 Breton '

N. alaseri

Triumph 4E
Rate X larvae/cvlinder
(nemas/ha) 14 DAT

% control
    Equivalent to 0.5,  1.0,  2.0 and 4.0  x 10* nemas/a,

    Ten 3rd instar larvae/cylinder; N =  6; means followed
    by the  same letter  are  not significantly different (P
    0.1; Duncan's [1955] multiple range  test).

    Calculated by Abbott's  (1925) formula.

                                TABLE 3
     Control of Northern masked chafer larvae with two rates of Neoaplectana carpocapsae "Breton1
 and N. qlaseri. Mllford Center, OH 1983.
X larvae/cvlinder
N. alaseri
N. carpocapsae
N. alaseri
N. carpocapsae
Triumph 4E
Oftanol 2F
Rate Top 2"
(nemas/ha) of soil
2.24 kg(AI)/ha
2.24 kg(AI)/ha

6.2 a
7.2 a
8.0 a
7.0 a
1.5 b
0 b
7.0 a
14 DAT % control
Entire Top 2"
soil plug of soil
.2 b 11
.0 ab 0
.5 a 0
.0 a 0
.8 c 86
.2 c 100
.2 ab
soil plug
Equivalent to 4.4 and 2.2x10*  nemas/a  respectively.

Ten 3rd instar larvae cylinder; N =  4;  means followed by
the same letter are not  significantly  different  (P =  0.1;
Duncans [1955] multiple  range test).

Calculated by Abbott's  (1925)  formula.

                                TABLE 4
     Mortality of Japanese beetle grubs caused by parasitic nematode strains.
 Nematode Strain
X of surviving larvae  (%  control)
2 DAT          4 DAT         7 DAT
1 Agr iotos '
' Breton '
'Breton x DD1361
. 'HP88'
( — )
(— )
   N. c. =  Neoaplectana carpocapsae;  H. = Heterorhabditis; 250

   Calculated by Abbott's  (1925)  formula.

                             TABLE 5
  Mortality of northern masked chafer grubs caused by parasitic nematode strains.
Nematode  Strain
X of surviving larvae  (% control)
2 DAT          4 DAT         7  DAT
1 Breton '
'Breton x DD136'
. 'HP88'
( — )
( — )
( — )
  N.  c.  = Neoaplectana carpocapsae;  H.  = Heterorhabditis;  250

  Calculated by Abbott's (1925)  formula.

                                 TABLE 6
    Mortality of Japanese beetle grubs caused by parasitic nematode strains.

Nematode Strain
1 Breton '
•Breton x DD1361
. 'HP88'


N. c
. = Neoaolectana
of surviving larvae (%
( 8)
carpocapsae ; H.
heliothidis; H. = Heterorhabdi
tis ?
21 DAT
( — )
h. = He t er orhabd itis
H. b. =
. bacter iophora ;
    450 nemas/vial.

    Calculated by Abbott's  formula.

                                    TABLE 7
    Average number of normal ±sd (% control) and nematode infected grubs per 0.09m2 per
treatment in Areas A and B.
  X Grubs (%)
           X  Infected
          Area  A (not irrigated)
              w/CL  nozzle
              w/CL  nozzle
              w/ph  nozzle
15.8± 8.9 ( 6%)a      2.1±2.6a
15.1+ 5.7 ( 7%)a
15.7+10.1 (10%)a
           Area B (irrigated)
             12.35 bill/ha
              w/CL  nozzle
              6.18 bill/ha
              w/CL  nozzle
             12.35 bill/ha
              w/ph  nozzle
              2.24 kgAI/ha
11.4+ 2.2 (25%)a
13.5+ 1.6 (ll%)a
 3.8+ 2.6
15.2+ 6.4
(76%)  b
(	)a
            0.5±0.4 b
            0.2+0.3 b
2.24 kg(AI)/ha
4.0+ 2.0 (76%) b
16.8+ 4.8 ( 	 )a
0.0+0.0 b
0.0+0.0 b
10.0+ 3.5 (34%)a      1.9+1.6a


0.0+0.0 b
0.0+0.0 b
           Means in the same column for each area followed with  the
           same letter are not significantly different (P = 0.05;
           Duncan's [1955] multiple range test)
            CL = ChemLawn shower head nozzle
            ph = Pinhole nozzle boom

                               TABLE 8
   Average number ±sd of Japanese beetle white grubs per 0.09m2 per plot 39 DAT with
entomogenous nematodes and insecticide followed with irrigation.
      Treatment                  X Grubs/0.09m2    (%  control)
    N. carpocapsae

       12.35xl09/ha                7.8+3.9 b          55%

    H. heliothidis

       12.35xl09/ha                4.5±3.3  c         74%

    Isofenfos 2F

         2.24 kg(AI)/ha             1.3+1.5   d        93%


         1.27cm water              17.3+5.9a           	
    Means followed by the same  letter are not significantly
    different (P = 0.05; Duncan's [1955] multiple range test).

       percent control determined  using Abbott's  (1925)  formula
       (pretreatment counts =16.9 grubs/0.09m2).

                              TABLE 9
  Sod Webworm mortality when subjected to various parasitic nematode strains 3 DAT.
Treatment	# Alive    # Dead     # Infected     %  Infected
Water Check            11          9           0              0

N. c.  'Breton1          3         17          17             85

N. c.  'Agriotis'        3         17          15             75

N. c.  'Italian1         1         19          12             60

  N.  c.  = Neoaplectana carpocapsae

                               TABLE 10

    Control of armyworm (Pseudaleta unipuncta) larvae using entomogenous nematodes and
Bacillus thuringiensis products.
N. c. 'All1
H. c. 'Mexican1
E. h. 'NC«
Chlorpyrifos 4E
Rate _
(nemas/ha) X
2.4 1/ha
2.4 1/ha
1.1 kg(AI)/ha
Larvae/cy 1 inder
0.0 A
0.4 A
1.8 B
6.6 C
7.2 CD
0.4 A
8.0 D
(% control)
   12.5X109 nemas/ha  = S.OxlO9 nemas/a;  2.4 1/ha =  1  qt/a; 1.1
   kg(AI)/ha = 1.0  lb(AI)/a.

   Numbers followed by the same letter are not significantly
   different (P = 0.05; Duncan's  [1955]  multiple range test).

   Calculated by Abbott's (1925)  formula.

                               TABLE 11
   Control of armyworms (Pseudaleta unipuncta) larvae using entomogenous nematodes and
Bacillus thuringiensis products.
H. h. 'NCf
N. b.
Chlorpyrifos 4E
Rate X
9.5 1/ha
9.5 1/ha
1.1 kg(AI)/ha
Larvae/ cyl inder
3.0 B
4.8 C
6.2 D
7.0 DE
0.0 A
7.8 E
(% control)
   12.5xl09 nemas/ha = 5.0xl09  nemas/a; 9.5  1/ha =1.0 gal/a;  1.1
   kg(AI)/ha =1.0 lb(AI)/a.

   Numbers followed by the  same letter are not  significantly
   different  (P = 0.05; Duncan's [1955] multiple range test).

   Calculated by Abbott's  (1925)  formula.

                                TABLE 12
     Percent mortality and percent confirmed infection of adult SL acletus confined on filter paper
innoculated with various rates of NL carpocapsae "Mexic
R&D Center, Boynton Beach, FL, 26 Dec 85.
N. c. 'Mexican'
N. c. 'All'
N. b. 'SN'
N. b. 'SN'+X77
Rate Replicate
an"or "AlP'or N.

bibionis "sn".ChemLawn

s % Mortality %

  N- c. =  Neoaplectana carpocapsae.  N. b. = N.  bibionis

  Based on dead insects with  various stages of  nematodes  in body
  cavity compared to number of replicates.

  X77 = Ortho X-77® spreader,  Chevron Chemical  Co., 0.3 ml/1.

                                TABLE 13

    Application of entomophageous nematodes to area A for mole cricket control, 11/.V/85 and
evaluated one week later.                                                 -, «iu
H. h.
H. h.
N. c.
N. c.
H. h
^— tI^4"^>"^M
• JL At* V^ >?^L ^^ J
X Mole Cricket
heliothidis; N. c.
Mounds/ Plot
7 DAT %
= Neoaplectana

 2.5xl09 nemas/ha = l.OxlO9  nemas/a;  12.4X109  nemas/ha =  5.0xl09


 Calculated using Abbott's (1925)  formula.

                               TABLE 14
    Application of entomophagous nematodes to area B for mole cricket control, 12/iv/85, and
 evaluated 6 days later.
                   Rate      X Mole Cricket Mounds/Transect
Treatment        nemas/ha        Pre-treat        6 DAT        %  Control

H. h.  'NC1        7.4X109            53             53              0
N. c.  'Mexican'  7.4xl09            28             15             42
Check                                28             26
  H. h*  = Heterorhabditis heliothidis; N. c. =  Neoaplectana

  7.4xl09  nemas/ha = 3.0xl09  nemas/a

  Calculated using Abbott's  (1925)  formula.

                               TABLE 15
    Application of entomophagous nematodes for mole cricket control, 27/iv/85, and evaluated
 11 and 19 days later.
X Mole Cricket Mounds/Plot
Pre-treat    11 DAT  19 DAT
% Control
N. c. 'Mexican'
N. c. 'Mexican1
Isofenphos 21
2.24 kg(AI)ha
62.4 72.4 	
67.2 78.0 	
55.2 34.2 4
60.6 74.0
N. c. = Neoaplectana carpocapsae; Isofenfos = Oftanol® (Mobay
  Chemical  Company)

  12.4xl09  nema/ha =  S.OxlO9 nemas/a;  4.9xl09  nemas/ha = 2.0xl09
  nemas/a;  2.24 kg(AI)ha =2.0 lb(AI)/a

  Calculated using Abbott's (1925) formula.

                                 TABLE 16
     Petri dish evaluation of entomogenous nematodes for infection of a range crane fly (Tipula
 spp.) larvae.
23/iv/86 Nemas/dish
N. b.
N. c. 'Mexican1
N. c. 'All'
H. h. 'NC1

% Mortality (N =
= 15)
= Neoaplectana
      Heterorhabditis  heliothidis.
N. c.  = N. carpocapsae; H. h. =

                                      FIGURE 1
    Pooled average wax moth larval mortality (N=5) for 3, 5, and 11 days after treatment (DAT)
at two soil depths (2.5 and 5.0 cm) followed by different amounts of irrigation (cm).
           4 -
           2 -
               5DAT 2.5cm
3DAT 5.0cm
3DAT 2.5cm
5DAT 5.0cm
               1 1DAT 5.0cm
               11 DAT 2.5cm
                       0.64          1.27
                      Irrigation Applied (cm)



                                George O. Polnar, Jr.
                        Department of Entomological Sciences
                               University of California,
                                 Berkeley, CA 94720
                                  Ramon Georgls
                               1057 E.  Meadow Circle
                                 Palo Alto, CA 94303
    For the present review, social insects are meant to comprise bees, wasps and ants of the order
Hymenoptera and  termites  of the order  Isoptera. Various diverse groups of nematodes are
associated with  these insects in nature  (Poinar, 1975, Bedding,  1986), either as  phoretics,
facultative or obligate parasites. However, our discussion will  be restricted to those nematodes
which show potential  in  regulating these insects in specialized  habitats and  which  can  be
manipulated by man to serve as biological control agents. The nematodes which fit these categories
today belong to the genera  Neoaplectana and Steinernema of the  Steinernematidae and
Heterorhabditis of the Heterorhabditidae.

    In the world today, there are some 2000 species of termites that are distributed into six families.
On the basis of their habits, termites have been placed into ecological groups which include the
drywood termites (Kalotermitidae) which live in dry wood and have little or no contact with soil, the
dampwood termites (Hodotermitidae) which live in buried timber or rotting logs and the subterranean
termites (Rhinotermitidae) which construct their nests in the soil and build protective shelter tubes
when searching for food  above ground (Edwards & Mill, 1986). Since the  subterranean termites
rely principally  on the  soil  for moisture, they are potential  hosts  for steinernematid and
heterorhabditid nematodes. Laboratory studies showed that Neoaplectana carpocapsae could  kill
workers of Coptotermes. Nasutitermes and Termes (in Poinar, 1979)  and Georgis et al (1982)
reported 96-98% mortality (N=10) of Zootermopsis and Reticulitermes three days after being placed
in standard petri dishes with 2000 infective stage  N. carpocapsae (Breton strain) (Fig. 1, 2) as well
as Heterorhabditis heliothidis. respectively.
    The next step was to test the effectiveness of these nematodes in the field. Some initial studies
using the DD-136 strain of hL carpocapsae against the Formosan termite Coptotermes formosanus


were reported by Reese (1971). In these studies, large numbers of termites were trapped, infected
with nematodes, and  returned to the colonies. The lack of success was attributed to the large
number of termites in a single colony, and because the termites in some colonies would recognize
infected workers,  then collect and isolate them behind earthen barriers.  This behavior was only
observed in some colonies however and it is not known if such actions constitute serious threats
to the use of nematodes against subterranean termites.
     In  1981, Bedding and Stanfield reported that by baiting with  a species of  Heterorhabditis
obtained from Australia, large laboratory colonies of Mastotermes were totally eradicated within a
week.  Nematode  suspensions were applied to termite-infested Pinus carabea plantations near
Darwin. Nematode-infected termites were recovered from neighboring untreated trees within one
week after treatment.  Each termite cadaver yielded about 10,000 nematodes and dead termites
were not walled off sufficiently to prevent exit of nematode progeny nor eaten by other termites or
associated mites. However, the investigators noted that there was a tendency for the termites to
vacate trees that had received nematode applications.
     In  1985, Mix reported studies conducted by R. Beal in Mississippi. Beal placed nematodes at
rates of 5,000 to 40,000/foot2 in a pine  forest and placed pine boards over the treated area. The
area was heavily infested with subterranean termites and as  the termites were attracted  to the
boards, they would encounter the nematodes. The boards were examined after one and two months
and the damage rated as percent of termite attack to the pine boards (see table 1). Although no
chemical treatment was applied for this experiment, the results reveal two interesting points. The
results are variable, however there is evidence that some nematode  species and strains are more
effective against termites than others. This variability in susceptibility  was also demonstrated using
Neoaplectana carpocapsae  (All  strain) and  Heterorhabditis heliothidis (NC strain)  in petri dish
experiments against Reticulitermes hesperus. Using a similar dose. N. carpocapsae killed the same
number of termites twice as quickly as hL heliothidis (Mangan & Miller, 1986). Secondly, although
Mix said that "There was no kill," the 40,000 applications of the Breton strain of N. carpocapsae
definitely did exhibit some "kill"and although it was not complete, it was better than the untreated
control. Also, it should be noted that even a dose of 40,000 nematodes per square foot is extremely
low to be used against an infinite supply of termites coming out of the soil.
     When  used  against subterranean termites attacking  dwellings, some success with the
nematodes was reported. Olkowski et al  (1985) reported on data supplied by Post and Drucker, two
pest control operators who  distributed SAF-T-SHIELD, a product  composed  of Neoaplectana
carpocapsae. On the basis of treating 4000 structures, they reported that the success rate for the
nematodes was about 80%,  compared to a 92% maximum  success rate with chlordane. Post
emphasized that it was very important to use a high dose, have adequate moisture and to position
the nematodes  as close to the structure as possible. Hall (1986) reported the experiences of Paul
Leek, a pest control operator in Pennsylvania. Leek treated some 38-40 houses with nematodes
and had a call back rate of only 13 percent (87% success).

     Using a Heterorhabditis isolate from Darwin, Australia, Danthanarayana and Vitarana (1987)
successfully controlled the live-wood tea termite, Glyptotermes dilatatus infesting tea plants in Sri
Lanka. The nematodes were applied to 50 tea bushes with a pipette inserted into the galleries inside
exposed stems  at a rate of 240,000 nemas per bush. At periodic intervals, the plants were uprooted
and examined to count living and nematode-infected individuals (see Table 2). Equally good results
were obtained using a pressurized knapsack sprayer with a hypodermic needle  in  place  of the
nozzle. About 1000 infective stage juveniles were produced in each of 32 parasitized termites after


8 days. The authors concluded that the nematodes from such cadavers parasitized healthy termites,
thus establishing a chain infection. Termite colonies were annihilated within 2-3 months with a
single nematode application, thus convincing the authors that these nematodes could be used to
control the tea termite in Sri Lanka.

     A recent study tested the efficacy of Neoaplectana carpocapsae against foraging workers of
Reticulitermes tibialis in a pasture in Colorado (Epsky & Capinera, 1988). The nematodes were
applied to the soil at a rate of 1 x 107 per m2 directly beneath the baited traps. There was a significant
decrease in number of termites per trap between treated and untreated traps and protection was
provided for a period of 2-3 weeks.

     A general  assessment of the above reports concerning  the  effect of nematodes  on
subterranean termites suggests several points. First, that it is difficult to compare results obtained
experimentally in field conditions (often with infinite numbers of termites) with situations associated
with controlling termites  in structures (where the number of termites  may be  large, but finite).
Second,  that although results reported by pest control operators who understand how to work with
biological organisms and apply adequate numbers of nematodes in choice areas, appear promising,
quantitative data on the number of termites killed and colony reduction is still lacking. Such data is
necessary before any official statement can be made regarding the effectiveness of neoaplectanid
nematodes in controlling subterranean termites in structures.

Ants, as Aculeate Hymenoptera, have the ability to sting and this fact, coupled with damage they
do in  constructing  their nests in human dwellings, is why control  measures are sometimes
     Early studies showed that under laboratory conditions, Neoaplectana carpocapsae  was able
to infect adults of the fire  ant, Solenopsis geminata. larvae and adults of Camponotus spp., larvae,
pupae and adults of the parasol ant, Acromyrmex octospinosus (Reich) (Kermarrec, 1975; Laumond
et al, 1979) and workers of Myrmica and Camponotus (Bedding, 1984). (Figure 3).
     Some interesting aspects of the association  between hJ.. carpocapsae and A. octospinosus
were discussed in a later work (Kermarrec et al, 1986). There appeared to be some host resistance
to nematode penetration  in mature pupae and adult  ants.  Besides a decline in penetration, there
was also a decrease in nematode development. Whereas penetration and development to the adult
stage occurred in 95-100% of the third and fourth stage larvae, penetration in older pupae dropped
to 5% and only 10% of these parasitized pupae contained nematode adults. Although adult ants
were killed none contained developing stages of the nematodes. When three million infectives of
N. carpocapsae were introduced  into the fungus  gardens of the ants, intense social grooming,
together with cleaning and building activities resulted in the elimination of the nematodes after ten
     Kermarrec et al (1986) point out some aspects to consider when infecting ants with nematodes.
If the ant contains an infra-buccal filter, then this device may  retain nematodes in the infra-buccal
pocket and not allow them to enter the pre-pharynx. Such a filtering device is usually absent in ant
larvae. If this device is effective in adult ants, then the nematodes would have to enter the buccal
area and force themselves through the pharyngeal glands  to enter the hemocoel. Aside  from
opening  size, other barriers hindering nematode infection in adult ants could be spinules in the
spiracular chamber, closure of the mouth and pilosity around the anus.


     In 1976, Poole completed a study on the use of Neoaplectana carpocapsae (=NL dutkyi) to
control the fire ants, Soienopsis richteri and S.. invicta in Mississippi. Reproductives and brood of
both species were susceptible to infection. Under laboratory conditions after 48 hrs, a mean dose
of 20 nematodes/inch3 resulted in 50% larval mortality, a mean dose of 31 infective juveniles/inch3
resulted in 50% pupal mortality and a mean dose of 109 nematodes/inch3 produced 50% mortality
of winged males and females. Poole found that the workers were less susceptible than the other
stages and could only achieve 50% mortality of media  workers when a mean dose of 880,000
nematodes/inch3 was used. A dose of 9,100,000 nematodes/inch3 was required to produce 50%
mortality of the minor workers after 48 hrs. It was concluded that the nematodes entered the adult
ants per o_s_.
     Using a concentration of  1 million nematodes per mound in the fall, the nematodes were
capable of causing 35% mortality (12% worker infection) up to 90 days post-treatment, reducing the
mound size by 18%. With the same concentration in the spring, 80% mortality was recorded (22%
worker infection) and the mound size was reduced by 28%. Greater colony mortality was achieved
against smaller colonies. In field tests against fL richteri. the nematodes destroyed 80% of the
mounds in the spring and 36% of the mounds in the fall.
     Reasons why the workers were infected less than  other stages were their greater overall
activity and grooming behavior. Also, workers regurgitated introduced nematodes to the alates and
larvae. A single winged male or female ant could produce up to 3,000 infective stage juveniles.
     Poole concluded  by stating that Neoaplectana would be an effective biological agent in the
control of the imported fire ants if timing of the application, mound size and climatic conditions were
taken into consideration.
     In 1980, Quattlebaum reported on tests with the DD-136  strain of NL carpocapsae and the
NC strain of HL heliothidis on mounds of the red imported fire ant, S, invicta and the black imported
fire ant, & richteri. in Boykin and Bounan Counties in South Carolina. Quattlebaum used a 2-gallon
compressed air sprayer calibrated to deliver 300 ml/20 sec.  in applying the nematodes  to the
mounds. A vertical hole 2 inches in diameter and 12-24 inches  deep was made into the center of
the mound. The sprayer wand was inserted into the mound and discharged for 20 sec. Check
mounds were sprayed with water. Assays were based on ant and mound mortality or the percentage
of inactive mounds in a plot. Mounds were considered active if any living ants were found associated
with them. Mortality was determined by holding fire ants  from treated mounds in large vials 24h
post-treatment and recording the number that died after 4 days. Control ants were taken from the
water-treated mounds. The results of two years' tests are shown in Tables 3 and 4.
     Quattlebaum (1980) concluded that both N. carpocapsae (DD-136) and H. heliothidis (NC-19)
were able to reduce field populations of the red imported fire ant (S. invicta). Of the two nematodes,
R carpocapsae gave the best control. Quattlebaum (1980) felt that this  might be the quicker
reproductive cycle of Neoaplectana in the nest, thus releasing more infective nematodes. He also
noted that results varied under conditions of different soil texture (sand versus silt) and it would be
desirable to note this condition  in further field testing.  In combining NL carpocapsae  (DD-136) with
various  insecticides (Sevin,  Pennwalt, Knox-out and Orthene) in field tests  against S, invicta.
Quattlebaum  (1980) found that a synergistic interaction often occurred between  insecticides and
nematodes. In  these  experiments a mound mortality of only 37.5% was  recorded when the
nematodes (N, carpocapsae  DD-136) were used alone at a rate of a 1 X 106 per mound. Recent
studies by Georgis (1987) show that desiccated nematodes (N. carpocapsae All) in a sugar solution

were infective to carpenter and harvester ants. Such formulations might be successful against fire
ants also.

                                 BEES AND WASPS

     Bees and wasps of the Aculeate Hymenoptera have the ability to sting and it is primarily this
character which necessitates their occasional control. It is mainly the social species of bees and
wasps that cause concern, the latter especially are attracted to food and produce.

     Bees are beneficial to man and are tested with biological insecticides for compatibility studies
so that the agents could be used against insect pests in the bee's environment.
     Whereas original reports indicated  that honeybee adults were resistant  to Neoaplectana
carpocapsae (Dutky & Hough, 1955; Cantwell et al,  1972), Hackett & Poinar (1973) showed that
adult worker honeybees could be parasitized and killed when infectives of  NL carpocapsae  were
added to sugar solutions, honey or a fruit concentrate which were fed to bees. The authors
suggested that nematode baits placed  outdoors for  yellowjackets should be unattractive to
honeybees. Kaya et al (1982) tested N. carpocapsae against worker and brood stages by spraying
infective juveniles on  frames in bee hives. They observed adult worker mortality but larvae and
pupae were not infected. Absence of parasitism in the brood was attributed to temperature ranges
between 33.3 and 35.2 C, which was detrimental to the infective stages. Desiccation of the infectives
under hive conditions  of high temperature and low relative humidity (40-78%) was also considered
to act as a nematode  mortality factor. The conclusions of the study were that general spraying of
nematodes in the vicinity of the hive and even direct spraying of the hive might kill some bees but
would  not be detrimental to the colony. If some worker bees did become infected, they would be
removed and the nematodes would not be able to recycle in the hive.  To reduce exposure of  bees
to nematodes applied  to the environment, applications could be done at times when the bees were
still in their hives (early morning or in the evening).
     Representatives  of the subfamily Vespinae of the family Vespidae include yellowjackets and
hornets of the genera Vespula and Paravespula. Yellowjackets in particular can constitute a serious
problem because of  their attraction to foodstuffs (sweet sources  or high protein substances
depending on the season). Although human deaths from yellowjacket stings in the United States
are rare (Parrish, 1963),  the  discomfort felt,  especially by hypersensitive individuals,  may be
considerable. In 1968, an estimated loss of $200,000 due to the action of Vespula spp. in agricultural
operations was reported  just in California  (Hawthorne,  1969).  Although  natural infections of
Vespinae by rhabditid nematodes would be unexpected, Bedding (1984)  reports discovering a
queen Vespuia germanica infected with hL carpocapsae. hibernating  beneath Eucalyptus bark in
     Initial studies showed that workers of Vespula pennsylvanica. V, rufa atropilosa and \A vulgaris
are killed by the infectives  of several strains of JSL carpocapsae as well as K heliothidis (Poinar &
Ennik,  1972; Gambino, 1984).
     There are  two basic methods of applying neoaplectanid nematodes to control yellowjackets.

One is to apply the nematodes directly to the nest, the other is to attract yellowjacket workers to
nematode-treated baits.
     Preliminary studies relating to the latter method were reported by Poinar and Ennik (1972)
when they showed that the workers of V, pennsylvanica and V, rufa atropilosa from California and
Vespula sp. from the Netherlands could be killed when  they Ingested infective  stages of  NL
carpocapsae (Agriotos strain) placed in a fruit concentrate or on sugar cubes. In order to avoid
attracting honeybees, the bait could be composed of a protein base such as tuna or other pet foods.
Such baits containing insecticides have  been successful in controlling yellowjackets in the field
(Ennik, 1973; Reid & MacDonald, 1986). If contamination was a problem, then utilizing synthetic
lures to attract the yellowjackets might be feasible (Davis et al, 1973).
     The problem of nematodes  drying out and dying in the baits could be alleviated by using
desiccated nematodes that revive when ingested by the hosts. Such desiccated nematodes have
been shown to be infective to \A pennsylvanica workers (Wojcik & Georgis, 1987).
     Introduction of aqueous suspensions of R carpocapsae into colonies of mixed populations of
\A pennsylvanica and E. vulqaris  in California were performed by removing some  of the overlying
soil  and making a hole in the exposed  nest envelope (Gambino & Pierluisi, 1987). The water
suspension of infective nematodes was poured in through the hole. Thirty-six hours after treatment,
the authors caught insects that were being carried out of the treated colonies  by yellowjacket
workers. Seventy percent  of these insects (both adults and larvae) had been parasitized by NL
carpocapsae. Prompt removal of infected individuals by healthy nestmates would eliminate recycling
of the nematodes and reduce their effectiveness.

     The use of nematodes for the control of social insects is beset with two difficulties. The first is
how to introduce the nematodes into the colony which may be concealed (termites, wasps) or have
a relatively small opening (ants). The other is how to establish cycling of the nematodes in diseased
members of the colony when the instinct of the workers is to avoid the diseased forms (termites)
or to remove them from the nest (wasps, ants).
     Thus, either a heavy dose  must be used in or near the colony in order to kill enough of the
workers or brood to reduce and hopefully eventually eliminate colony activity or a nematode-treated
bait be used that the workers will take and feed to the  developing brood. Attempts  at killing the
queen may  be difficult and successful only in single queen colonies  where new queens are not
readily produced. New types of formulation, such as embedding the nematodes in calcium alginate
together with an attractant (Poinar et al., 1985) or utilizing desiccated nematodes in baits (Georgis,
1987) may result in innovative delivery systems that could be used against social insects.
     The success of these efforts will depend on the ingenuity of the researcher in understanding
the biology and behavior of the insects involved in order to utilize the nematodes effectively in any
control program.


Bedding, R.A. 1984. Nematode parasites of Hymenoptera. In: Nickle, WR. "Plantand Insect Nematodes."Marcel Dekker
        N.Y. 755-795.

Bedding, R.A. and M. Stanfield. 1981. Nematodes for insect control. Mastotermes. In: CSIRO Division of Entomoloav
        Ann. Rpt. 1979-80.

Cantwell, G.E., T. Lehnert and J. Fowler. 1972. Are biological insecticides harmful to the honey bee? Amer Bee J

Danthanarayana, W.  and S.I. Vitarana.  1987. Control of the live-wood tea termite, Glvptotermes  dilatatus using
        Heterorhabditis sp. (Nemat.). Agr., Ecosyst. Environ. 19:333-342.

Davis, H.G., R.W. Zwick, W.M. Rogoff, T.P. McGovern and M. Beroza. 1973. Perimeter traps baited with synthetic lures
        for suppression of yellow-jackets in fruit orchards. Environ. Entom. 2:569-571.

Dutky, S.R. and W.S. Hough. 1955. Note on a parasitic nematode from codling moth larvae, Carpocapsa pomonella.
        Proc. Ent. Soc. Wash. 57:244.

Edwards, R. and A.E. Mill. 1986. Termites in buildings. Rentokil Ltd., 261 pp.

Ennik, F. 1973. Abatement of yellowjackets using encapsulated formulations of Diazinon and Rabon. J.  Econ. Entomol.

Epsky, N.O.  and J.L. Capinera. 1988. Efficacy of the entomogenous nematode Steinernema feltiae against  a
        subterranean termite. Reticulitermis tibialis (Isoptera: Rhinotermrtidae). J. Econ. Entomol 81:1313-1317.

Gambino, P. 1984. Susceptibility of the western yellowjacket Vespula pennsylvanica to three species of entomogenous
        nematodes. IRCS Medical Sci. 12:264.

Gambino, P. and G. J.  Pierluisi. 1987.  Eusocial Paravespula wasps remove diseased nestmates  from the colony.
        Unpublished report. 9 p.
Georgis, R. 1987. Nematodes for biological control of urban insects. Amer. Chem. Soc.-Div. Environ. Chem. 194th Natl.
        Mtg., New Orleans, LA 27:816-821.
Georgis, R., G.O. Poinar, Jr. and A.P. Wilson. 1982. Susceptibility of damp-wood termites and soil and wood-dwelling
        termites to the entomogenous nematode, Neoaplectana carpocapsae. IRCS Med. Sci. 10:563.

Hackett, K.J. and  G.O.  Poinar, Jr.  1973.  The  ability of Neoaplectana carpocapsae Weiser (Steinernematidae:
        Rhabdrtoidea) to infect adult honeybees (Apis mellifera. Apidae: Hymenoptera). Amer. Bee Journal 113:100.

Hall, R. 1986. Down but not out. Pest Control 54:60-62, 91-92.
Hawthorne, R.M. 1969.  Estimated damage and crop  loss caused by insect/mite pests - 1968. California Dept. of
        Agriculture. Bureau of Entomology, unpublished report, 11  pp.
Kaya, H.K., J.M.  Marston, J.E. Lindegren and Y.-S.  Peng.  1982. Low susceptibility of the honey bee, Apjs mellifera L
        (Hymenoptera: Apidae) to the entomogenous nematode, Neoaplectana carpocapsae Weiser. Environ. Entomol.
Kermarrec,  A. 1975. Etude des  relations synecologiques entre  les nematodes et la fourmi-manioc:  Acromyrmex
        octospinosus ReiclvAnn. Zool.-Ecol. Anim. 7:27-44.
Kermarrec, A., G. Febvay and M. Decharme. 1986. Protection of leaf-cutting ants from biohazards: Is there a future for
        microbiological control? In: Fire Ants and Leaf-Cutting Ants. Eds. C.S. Lofgren & R.K. Van der Meer. Westview
        Press, Boulder, pp. 339-356.
Laumond, C., H. Mauleon & A. Kermarrec. 1979. Donnees nouvelles sur le spectre d'hotes et le parasitisme du nematode
        entomophage Neoaplectana carpocapsae. Entomophaga 24:13-27.

 Mangan, D. and R. Miller. 1986. Biosys unpublished report. 2 pp.
 Mix, J. 1985. Seal's research shows nematodes don't control subterranean termites. Pest Control 53:22-23.
 Parrish, H.M. 1963. Analysis of 460 fatalities from venomous animals in the United States. Amer. J. Med. Sci. 36:129-140.
 Poinar, Jr., G.0.1979. Nematodes for biological control of insects. CRC Press, Boca Raton, Florida. 277 pp.
 Poinar, Jr., G.O. and F. Ennik. 1972. The use of Neoaplectana carpocapsae (Steinernematidae: Rhabditoidea) against
         adult yellowjackets (Vespula spp.. Vespidae: Hymenoptera). J. Invert. Path. 19:331-334.
 Poinar, Jr., G.O.,  G.M. Thomas,  K.C. Lin and P. Mookerjee. 1985. Feasibility of embedding  parasitic nematodes in
         hydrogels for insect control. IRCS Med. Sci. 13:754-755.
 Poole, M.A. 1976.  Survey and control efficacy of endoparasites of Solenopsis richteri Forel and Solenopsis invicta Buren
         in Mississippi. Ph.D. thesis. Mississippi State University, Mississippi State. 83 pp.
 Reese, K.M. 1971. Navy fights Formosan termite in Hawaii. Chem. & Engineer. News (Oct. 11). p.52.
 Reid, B.L. and J.F.  MacDonald.  1986.  Influence of meat texture and toxicants upon  bait collection by the German
         Yellowjacket (Hymenoptera: Vepsidae). J. Econ. Entomol. 79:50-53.
 Wojcik, W.F. and R. Georgis. 1987. Infection of selected insect species with desiccated Steinernema feltiae (Nematoda).
         Abst. Soc. Invert. Path. 20th Ann. Meeting, July 20-24,1987, Gainesville, Florida, p.77.

                                TABLE 1
Percentage of damage caused by subterranean termites to pine boards placed over areas
 treated with Neoaplectana and Heterorhabditis. respectively (modified from Mix, 1985).
(sq. ft.)
                                                       Percent  of Damage
                                                    1 month        2 months
Heterorhabditis sp.
  N. carpocapsae
  N. carpocapsae
  Untreated Control

                                     TABLE 2
     Mortality of the live-wood tea termite, Glyptotermes dilatatus after applying Heterorhabditis sp.
 to tea bushes at a rate of 240,000 nemas per plant (modified from Danthanarayana and Vitarana
   Days  after
Total number
of termites
 per plant
Total number
of termites
100 380
100 773

                                    TABLE 3
    Mortality of fire ant (£L invicta) mounds treated with the DD-136 strain of fL carpocapsae
(approximate figures obtained from Figures 6 and 7 of Quattelbaum (1980)).
                                    % Mortality                Z Mortality
   (nematodes/mound)              after 30 days              after 180 days

      Control                          7A (5)B                   15  (9)

      0.5  x 106                      57 (55)                    72 (81)

      1    x 106                      85 (68)                    93 (86)

      2    x 106                     100 (97)                    99 (98)
    A * numbers represent 1978 tests.

    B * numbers in parentheses represent 1979 tests,

                                     TABLE 4
    Mortality of fire ant (S, invicta) mounds treated with the  NC-19 strain of Heterorhabditis
heliothidis (approximate figures obtained from Figures 8 and 9 of Quattelbaum (1980)).
         Dose                       % Mortality                Z  Mortality
     (nemat odes /mound)              after 30 days              after 180 days
        Control                          6* (5)B                    12  (9)

        0.5 x 106                        -  (40)                       - (52)

        1    x 106                      64  (69)                      64 (70)

        2    x 10°                      89  (80)                      89 (82)
     A •  numbers represent 1978 tests.

     B »  numbers in parentheses represent  1979  tests

                                FIGURE 1
A worker of Reticulitermes surrounded by infective stages of Neoaplectana carpocapsae.

                                     FIGURE 2
     Developing stages and adults of Neoaplectana carpocapsae removed from the body cavity of
an infected Reticulitermes.

                                    FIGURE 3
    Fire ant queen surrounded by developing stages of Neoaplectana carpocapsae removed from
the host's hemocoel. Specimen courtesy of Brad Vinson, under whose direction the fire ant control
program with entomogenous nematodes is being conducted.


Manual of Current Practices for
Control of Turfgrass Diseases,
   Insects and Poa Annua


                        NORTHERN REGIONS
                            Peter H. Dernoeden, Ph.D
                            Department of Agronomy
                            The University of Maryland
                             College Park, MD 20742

    Most turfgrass diseases are caused by pathogenic fungi that invade leaves, stems and roots
of plants. As a result of the injurious effects of a disease, the plant will exhibit various symptoms
such as leaf spots,  root rots or death of leaves, tillers or entire plants. Sometimes these fungi
produce visible signs such as mushrooms; white powdery mildew; white, fluffy mycelial growth; pink
gelatinous mycelial growth; red or black pustules on leaves, etc. Mycelium is the vegetative body
of a fungus that is composed of a network of fine tubes that often appear cottony. It is through the
use of these symptoms and signs that disease problems are diagnosed. Time of year and turfgrass
species also provide important clues in diagnosing diseases. For example, brown patch and Pythium
blight are seldom a problem when night temperatures fall below 65F, and Pythium blight does not
cause severe injury to mature stands of Kentucky bluegrass. Conversely, dollar spot tends to be
more damaging under conditions of cooler nighttime temperatures in late spring and early fall than
during the hottest weeks of summer. Summer patch is strictly a high temperature, summer disease
of Kentucky bluegrass, fine leaf fescues and annual bluegrass. Species such as perennial ryegrass,
creeping bentgrass and  tall fescue are resistant to summer patch.
    Most turfgrass diseases are caused by fungi rather than bacteria or viruses. In the pages to
follow, the most common fungal diseases of turfgrasses, as well as plant parasitic nematodes, are
described and cultural and chemical approaches to their management are outlined. A more complete
list of turfgrass diseases, hosts and pathogens is provided in Table 1.
                       SPRING AND FALL DISEASES

    The dollar spot pathogen (Sclerotinia homoeocarpa) is widespread and extremely destructive
 to turfgrasses. The disease is known to attack most turfgrass species including annual bluegrass,
 bentgrasses, red fescue,  Kentucky bluegrass, perennial ryegrass, bermudagrass, zoysiagrass,
 centipedegrass and St. Augustinegrass. The symptomatic pattern of dollar spot varies with turfgrass
 species and management practices. Under close mowing conditions, as with intensively maintained
 bentgrass or zoysiagrass, the disease first appears as small, circular, straw-colored spots of blighted
 turfgrass about the size of a silver dollar. With coarser textured grasses such as Kentucky bluegrass


or perennial ryegrass suited to higher mowing practices, the blighted areas are considerably larger,
irregularly-shaped, straw-colored  patches three to six inches in diameter.  Affected patches
frequently coalesce and  involve large areas  of turf. Grass blades often  have straw-colored or
bleached-white lesions shaped like an hour glass. The hour glass banding on the leaves is often
made more obvious by a definite narrow brown, purple, or black band which borders the bleached
sections of the lesion from the remaining green portions. When the fungus is active and moisture
is present, a fine, cobwebby mycelium may cover the diseased patches during early morning hours.
Disease severity has peak periods in late spring-early summer and again late summer-early fall. In
the upper Midwest, however, the disease tends to be most damaging during autumn. Dollar spot
can remain active during mild periods throughout fall and into early winter in some regions.
     There are at least two strains of the dollar spot fungus, (referred to tentatively as species of
Moellerodiscus and Lanzia) which may account for the ability of the disease to be damaging during
cool and warm periods. Presently, the taxonomy of the two strains is imperfectly understood. Dollar
spot tends to be  most damaging in poorly nourished turfs, particularly if soils are dry  but when
humidity is high or when a heavy dew is present. Avoiding drought stress, watering deeply during
daytime hours, maintaining a  balanced N-P-K fertility program,  and  controlling thatch and
compaction are cultural approaches that minimize dollar spot injury. Except for maneb, mancozeb
and thiram, most fungicides effectively control dollar spot.

     Many of the fungi that cause leaf spotting and melting-out diseases of turf grasses were once
assigned to the genus Helminthosporium. Today, these fungi are more appropriately referred to as
species of Drechslera or Bipolaris. but the common name of the diseases they cause remains
Helminthosporium leaf spot, melting-out or netblotch.
     Among the most important spring and autumn diseases of Kentucky bluegrass is  leaf spot,
which is caused by Drechslera poae. This disease is not as devastating as it once was because of
the development and widespread use of resistant bluegrass cultivars. South Dakota, Kenblue, Park
and other "common"types of Kentucky bluegrass are very susceptible to leaf spot. The common
types, which generally survive extreme environmental stresses, are still used today as components
of bluegrass blends in some regions of the U.S. because they lend genetic diversity to the stand.
     Drechslera poae is a cool weather pathogen that is most active during the spring (especially
April and May), autumn (especially September and October), and throughout mild winter periods.
CX poae causes disease that may occur in two phases: the leaf spot phase, and the melting-out
phase.  Typically, distinct purplish-brown leaf spot lesions with a central tan spot are produced on
the leaves of affected plants. In a heavily infected stand, the turf appears yellow or red-brown in
color when observed from a standing position. During favorable disease conditions, lesions may
increase in size to encompass the entire width of the blade causing a die-back from the tip. Leaf
spot lesions are initially associated with older leaves, which die prematurely as a result  of the
invasion. If favorable environmental conditions for disease continue, particularly overcast, cool and
drizzling weather, successive layers of leaf sheaths are penetrated, and the crown is invaded. Once
the crown is invaded the disease enters the melting-out phase. During this phase, entire tillers are
lost, and the turf loses density. Hence, it is the melting-out phase that is most damaging to the sward.
     Net-blotch disease  of tall fescue and perennial  ryegrass is  caused by another of the
helminthosporia, Drechslera dictyoides. IX dictyoides is also a cool, wet weather pathogen that

attacks turf primarily during cool and moist periods of spring and fall. Initially, symptoms appear as
minute, purple-brown specks on leaves. As the disease progresses, a dark brown, net-like pattern
of necrotic lesions develop on tall fescue. These net blotches may coalesce, leaves turn brown or
yellow, and die-back from the tip. On leaves of perennial ryegrass, numerous oblong, brown lesions
are produced. Under  ideal  environmental conditions the fungus may invade crowns and roots,
causing a melting out of the stand. Both diseases can be active during relatively warm, rainy periods
of winter.

     Cultural practices that  minimize injury from leaf spot or melting-out diseases are as follows:
raise the mowing height; avoid spring and summer applications of water soluble nitrogen fertilizers;
avoid light, frequent irrigations; control thatch; overseed with resistant  cultivars; and avoid the use
of broadleaf, phenoxy herbicides during periods when these diseases are active. Fungicides that
effectively control leaf spot disease include anilazine, chlorothalonil, iprodione and maneb.

     Spring dead spot (SDS) is perhaps the most damaging disease of bermudagrass turf and is
caused by Leptosphaeria korrae and possibly other fungi. As the name implies, SDS injury becomes
apparent in the spring. The actual infection, however, may begin as early as autumn, but root injury
by the pathogen becomes  rapid prior to spring green-up, during  late winter or early spring. As
bermudagrass breaks dormancy, circular patches of brown, sunken turf two inches to three feet in
diameter  become  conspicuous. Rhizomes and stolons from nearby, healthy  plants eventually
spread into and cover the dead patches. This filling-in process is slow, a period which may last four
to eight weeks following spring green-up. The slow filling  process is  believed to be due to  toxic
substances generated in the soil below the dead patches. Weeds commonly invade the dead
patches. These  weeds  should  be  controlled to reduce competition with the bermudagrass  and
thereby speed up the recovery process.
     Spring dead spot is most commonly associated with  mature  bermudagrass turfs older than
three years. The disease, however, may appear the spring following sprigging with stolons from sites
that previously had SDS. SDS injury is most likely to occur where thick thatch layers exist and where
nitrogen fertilizers have  been heavily applied during late summer.  Benomyl and  fenarimol applied
in late September  help alleviate SDS. Ammonium sulfate  (applied at  1.0 Ib N/1000 ft) and other
water soluble nitrogen fertilizers plus potassium (applied at 1.0 Ib K/1000 ft) applied on  monthly
intervals from mid-May to mid-August speed the recovery of turf injured by SDS.


     Necrotic ring spot (MRS) is a newly described disease of Kentucky bluegrass and is caused
by Leptosphaeria korrae. Although newly described, MRS probably has been around for some time,
but has been confused with Fusarium blight.
     Necrotic ring spot was first suspected as being a new disease in Wisconsin, where the fungicide
triadimefon had  been  applied unsuccessfully to control what was believed to be Fusarium blight.
Unlike Fusarium blight, NRS primarily is a cool, wet weather disease  of spring and fall. Fusarium
blight and another recently  described patch disease that mimics Fusarium blight,  summer patch,
are  both  high-temperature  diseases of summer. The  confusion over NRS, summer patch and
Fusarium blight has occurred because all three diseases can appear  as rings of dead grass with

living turf in the center. To date, NRS has been observed mainly in Kentucky bluegrass turf grown
in the Northeast, upper Midwest and Pacific Northwest regions.
     Currently, there is no information regarding cultural control of NRS or cultivar susceptibility to
the disease. Early spring applications of fenarimol and propiconazole have been reported to control

     Stripe (Ustilago striiformis) and flag smut (Urocystis agropyri) are diseases that occur primarily
in mature Kentucky bluegrass stands and occasionally in bentgrass and perennial ryegrass turf.
Symptoms are most conspicuous during the cool, moist seasons of spring and fall. Infected plants
are often stunted and pale green or yellow in color. Narrow, silvery or gray-black streaks will appear
on the leaves.  These streaks are fruiting structures (sori) in which large masses of spores
(teliospores) are produced. When sori mature, the cuticle and epidermis rupture, and the leaves
shred  and curl  releasing the  teliospores. During summer months, infected plants may appear
amazingly healthy if properly maintained. In spring or autumn, however, badly infected stands may
appear chlorotic and in need of nitrogen fertilizer. During winter, leaves that had been shredded by
matured fruiting  bodies develop a gray-brown, desiccated appearance.
     Stripe and flag smut are most damaging to infected plants during periods of heat and drought
stress. If properly irrigated and fertilized, however, badly smutted stands often survive, exhibiting
only a decrease in  turf quality and some thinning  during stressful summer months. These smut
diseases  most commonly occur in mature (two to four years  and older) stands that have  been
managed with high levels of nitrogen fertilizer.  Merion, Windsor and Fylking Kentucky bluegrasses
are among the most susceptible cultivars. Recently introduced cultivars are less susceptible to these
diseases, which has led to a reduction in the occurrence of stripe and flag smut. Using a balanced
N-P-K fall fertilizer program, increasing the mowing height in summer and deep irrigation at the first
sign of drought  stress are  effective management  practices that greatly minimize smut injury in
Kentucky bluegrass. Hence, cultural control of smut diseases is aimed at blending disease resistant
cultivars,  avoiding excessive use of nitrogen  fertilizer, controlling thatch and preventing severe
drought stress of infected  turfs.  Smut diseases are effectively controlled with  a spring  or fall
application of a systemic fungicide such as benomyl, fenarimol, propiconazole, or triadimefon.

     Red  thread (Laetisaria fuciformis) is a common disease of turfgrasses, and  its development
is favored by cool (65-75F), wet and extended overcast  weather of spring and fall. Red thread may
also occur during warm to very cold  weather in the presence  of plenty of surface moisture or at
snow melt in winter. This disease may become widespread among turfgrass species during mild
     Red thread is most damaging to perennial ryegrass, common-type Kentucky bluegrasses, and
the fine leaf fescues.  Red thread  may also attack improved cultivars  of Kentucky bluegrass, tall
fescue, bentgrass, and bermudagrass, but generally does not cause a significant level of injury to
these species when they are sufficiently fertilized with nitrogen.
     The symptoms and signs of red thread are distinctive and unmistakable. In the presence of
morning dew or rain, a coral pink or reddish layer of gelatinous fungal growth (mycelium) can easily
be  seen  on  leaves and sheaths.  The  infested green leaves of these plants soon become

water-soaked in appearance. When leaves dry, the fungal mycelium becomes pink in color and is
easily seen on the straw-brown or tan tissues of dead leaves and sheaths. During the final phase
of disease activity, bright red, hard and brittle strands of fungal  mycelium called "red threads" or
sclerotia may be seen extending from leaf surfaces, particularly cut leaf tips. These red threads fall
into the thatch  and serve as resting structures for the fungus by surviving long periods that are
unfavorable for growth of the pathogen. From a distance, affected turf has a straw-brown, tan or
pinkish color. Symptoms are concentrated  in circular or irregularly shaped patches two inches to
three feet in diameter that frequently coalesce to involve the whole sward.

     Red thread is generally most injurious to poorly nourished  turfs. Frequently, the  disease is
best controlled by an application of 0.5-1.0 Ib nitrogen/1000 ft. Application of nitrogen during periods
too cool for turf growth will not aid in reducing disease severity. This is because nitrogen alleviates
red thread disease symptoms by stimulating plant growth and vigor. The nitrogen-stimulated plants
are able  to replace damaged tissues more rapidly than the fungus can inflict injury. Fungicides that
control red thread  are anilazine, chlorothalonil, iprodione and triadimefon.

     Powdery mildew (Erysiphe graminis)  is a disease confined to shaded  environments. The
presence of grayish-white mycelium and spores on the upper surfaces of leaves is a conspicuous,
diagnostic sign of the disease. The lower,  older  leaves of the plant are  generally more heavily
infected than upper, younger leaves. In heavy infestations, leaves  appear to have been dusted with
ground limestone  or flour. The abundant surface  mycelium absorbs nutrients  from the epidermal
cells and the leaves turn yellow. Eventually leaves and tillers may die and  the turf will exhibit poor
density.  The fungus  seldom  kills plants; however,  its  presence severely weakens plants and
therefore can predispose them to injury from environmental stresses or other diseases.
     Powdery mildew can be found at almost any time of year, but peak activity normally occurs in
the fall. Spores are produced in abundance on leaf surfaces and they move  rapidly to adjacent,
healthy leaves. The spores germinate rapidly, even in the absence of dew or water. Disease activity
is most prevalent during cool, humid and cloudy periods of spring and fall. Because shade is the
primary predisposing factor for powdery mildew, reducing shade and improving air circulation is a
cultural,  but often  impractical approach  to reduce  damage.  Planting or overseeding  with
shade-tolerant cultivars, increasing mowing  height, avoiding drought stress and using a balanced
fertilizer  program will promote turfgrass growth and help to minimize injury from powdery mildew.
Fungicides should be applied  in situations where the disease is yellowing  plants and thinning the
stand. Some effective fungicides are benomyl, propiconazole and  triadimefon. Tank mix  a leaf spot
fungicide with the mildewcide.

     Rust diseases in turf are  caused by several Puccinia spp.  and they are most damaging to
poorly nourished turfs and turfs grown under a low mowing height. Stem rust (P±  graminis) of
Kentucky bluegrass, crown rust (P, coronata) of perennial ryegrass,  and zoysiagrass rust  (IL
zoysiae) are  most  commonly observed during cool, moist periods  of fall. Rust-affected turfs exhibit
a yellowish or reddish-brown appearance from a distance. Close inspection  of diseased leaves
reveals the presence of conspicuous red, black,  orange or yellow pustules. Sterol inhibiting
fungicides (such as propiconazole and triadimefon) effectively control rust. Contact fungicides (such
as chlorothalonil, maneb and mancozeb) will help  somewhat to alleviate injury. A balanced fertility

program may be preferred to fungicides in situations where rust is damaging poorly nourished turfs.
Also, irrigate early in the day to insure leaf dry ness prior to nightfall, water deeply but infrequently,
increase mowing height and increase mowing frequency. By increasing mowing frequency, leaves
bearing immature spores are removed and this reduces the potential for more leaf infections.
                                SUMMER DISEASES

     Brown patch is caused by Rhizoctonia solani and it is a common, summertime disease of
turfgrasses. In southeastern states. R. zeae may also cause symptoms typical of brown patch. The
pathogen attacks nearly all grasses  used as turf, but  is most damaging to tall fescue, perennial
ryegrass, creeping bentgrass and annual bluegrass. Kentucky bluegrass, zoysiagrass and other
species are only occasionally injured by Rhizoctonia solani. The symptoms of the disease vary
according to host species. On closely mown turf, affected patches are roughly circular and range
from three inches to three feet or greater in diameter. The outer edge of the patch may develop a
one to two inch wide smoke ring. The smoke ring is blue-gray in color and is caused by mycelium
in the active process of infecting leaves. Smoke rings are not always present and patches may
have an irregular rather than circular shape. Close inspection of leaf blades reveals that the fungus
primarily causes a dieback from the tip down, to give affected turf its brown color. In tall fescue and
perennial ryegrass turfs, affected areas are frequently irregularly shaped  and smoke rings are only
occasionally present. EL  solani  produces distinctive and often greatly elongated lesions on tall
fescue leaves. The  lesions are a light, chocolate brown color, and are bordered by narrow, dark
brown bands of tissues. In perennial ryegrass, smaller leaf lesions are produced and tip dieback
commonly occurs.  During early morning hours,  when  the  disease is  active, the  cobweb-like
mycelium may be observed on leaves in the presence of water or heavy dew.
     Environmental  conditions that favor disease development are day  temperatures above 85F
and high relative humidity. A night temperature above 68F is perhaps the most critical environmental
requirement for disease  development.  Although textbooks underscore  the importance of high
surface moisture or high soil moisture in disease severity, the disease can be very damaging to
wilted tail fescue and perennial ryegrass if the relative humidity  is high. Summer application of
fertilizers, in particular water soluble N fertilizers, may enhance disease injury  from brown  patch.
Avoiding nitrogen when the disease  is active and irrigating early  in the  day  are the only cultural
practices  that may help alleviate  brown  patch. Benomyl, chlorothalonil,  iprodione, maneb,
mancozeb, propiconazole and the thiophanates effectively control brown  patch.

     Pythium blight is among the most destructive turfgrass diseases. During periods of high relative
humidity,  nighttime  temperatures above 70F and abundant surface moisture, the disease may
progress rapidly, destroying large turf areas within 24 hours. The disease often  is first observed in
areas that are shaded, low lying and adjacent to water where air circulation is poor. While there are
several species capable of causing the disease, P. aphanidermatum and P± ultimum are the most

    It is a general misconception that Pythium blight is a common, widespread disease. Although
Pythium spp. can cause damping-off of any seedling species, it rarely, if ever, attacks mature lawns

comprised of Kentucky bluegrass, tall fescue, fine fescue or zoysiagrass.  Pythium blight is most
likely to  attack creeping bentgrass or  perennial ryegrass grown under the high management
conditions commonly found on golf courses.

     On closely mown bentgrass putting greens, the disease kills turf in circular patches, rings or
streaks that follow the water drainage pattern. During morning hours when the disease is active,
bentgrass turf displays an orange-bronze color and there may be a gray smoke ring on the periphery
of affected patches. In low lying areas where water collects the patches are  brown and all plants
are often  killed. In perennial ryegrass, affected foliage develops a dark-gray color and leaf blades
have a water soaked appearance. Blades then collapse, mat together and turn brown.
     A cottony web of mycelium covers  the grass leaves and is visible during early morning hours
when leaves are wet. Pythium spp. are  capable of producing an abundance of mycelium in a few
hours, which bridges leaf blades, giving turf the cottony appearance. The fungus primarily spreads
over a turf by rapid mycelial growth or by movement of mycelial fragments in rain or irrigation water.
Pythium  species  also produce motile spores called zoospores,  which also  serve to  spread the

     Water management may greatly influence disease severity. It is therefore  helpful to water early
in the day to avoid a moist foliage prior to nightfall. Improving water and air drainage will help reduce
disease development, but these cultural measures are often expensive and difficult to achieve. A
fall fertilization program using a balanced N-P-K fertilizer, avoiding the use of lime in alkaline soils
and avoiding nitrogen fertilizers during summer stress periods may help to reduce disease incidence
and severity.
     While fungicides are not generally used in  lawn care for Pythium blight control, they are
considered a necessity in golf course management in most regions of the U.S. Before the advent
of systemic fungicides targeted for Pythium blight in the early 1980's, the disease was combatted
with short residual chemicals such  as chloroneb and etridiazol. Metalaxyl was registered for use
on turf in 1981 and provides  over 20 days of control and can be used either preventatively or
curatively. The widespread reliance and continuous usage of metalaxyl on golf courses has led to
reduced effectiveness and  in some cases  the selection of Pythium spp. biotypes resistant to
metalaxyl. Reduced residual effectiveness is attributed to a build-up of microorganisms that degrade
the active ingredient of the fungicide. Propamocarb and fosetyl-AI are other fungicides that provide
long, residual Pythium  blight control, but they should  be applied preventatively  and they are
expensive to use.
     To  avoid  the build-up of  fungicide resistant  biotypes  and to avoid  reduced  residual
effectiveness of compounds due to microbial build-up, fungicides should always be rotated and
they should be applied in tank-mix combinations whenever economically feasible. Recent research
indicates  that the aforementioned  problems can be avoided by tank mixing reduced rates of
metalaxyl and propamocarb or reduced rates of metalaxyl + propamocarb + fosetyl-AI. Tank mixing
metalaxyl with mancozeb is also believed to help reduce the probability of resistant Pythium biotypes
from dominating.  Alternating systemics  with contact sprays, although the  latter may only provide
three to seven day control, will also  help to reduce these potential problems from occurring.


     Summer patch is incited by Magnaporthe poae and is a most destructive disease of Kentucky
bluegrass and  annual bluegrass turf.  Symptoms of summer patch  initially appear  as wilted,
dark-green areas of turf. Initially the straw-brown dead patches resemble the symptoms of dollar
spot disease, but these patches soon increase in size and may take on crescent shapes, elongated
streaks, or circular patches. Healthy turf may persist in the center of blighted patches producing
rings or "frog eye" symptoms. The frog eye symptom, however, is only occasionally observed and
the dead patch symptom is more commonplace. Affected regions may coalesce, and large areas
of turf are destroyed within a seven to ten day period. There are no distinctive leaf lesions associated
with the disease, but leaves generally dieback from the tip.
     Summer patch most commonly occurs in Kentucky bluegrass turfs that are three years of age
or older. To date, the disease  has principally been a problem in  Kentucky bluegrass, annual
bluegrass and fine leaf fescues. Environmental conditions play a significant role in the predisposition
of turf to the disease. The disease generally appears in late June or early July when daytime
temperatures above 90F prevail. The disease is most severe on sunny, exposed slopes or other
heat-stressed areas of lawns such as those adjacent to paved walks and driveways. The disease
most frequently occurs following a period of drought stress. Turf allowed to enter drought-induced
dormancy is often severely damaged. Mysteriously, the disease may flair up following rainy periods
in late summer  and September. Other  predisposing factors include: spring applications of high
levels  of nitrogen fertilizer, accumulation of thatch, frequent light irrigations or rain storms, and
compaction. The most important environmental factor required for disease development is for root
zone temperatures to exceed 86F. For home lawns, increasing  mowing height to 3.0 inches in late
spring, applying water deeply and only at the onset of wilt and use of a slow release nitrogen fertilizer,
such as  sulfur coated urea, are the best approaches  to minimizing  summer patch. Preventative
applications of triadimefon, or curative applications  of benomyl or iprodione drenches may provide
a satisfactory level of control on close-cut Kentucky bluegrass fairways, but no fungicide program
is known to control the disease in annual bluegrass on putting greens. Fungicides are ineffective if
turf is allowed to enter drought induced dormancy.

     Fusarium blight was first observed in the late 1950's, but is a controversial disease that primarily
attacks Kentucky bluegrass. A complex of Fusarium culmorum and R poae were implicated as the
incitants  of the disease. Fusarium  blight occurred in California primarily as a severe crown rot;
whereas in the eastern U.S., the foliage blight symptom is most commonplace. Early symptoms first
appear as scattered, light-green or wilted patches two to six inches in diameter. Over a period of
36-48  hours, under high-temperature stress conditions, patches fade to  a tan or light-straw color.
Affected  areas may take on crescent shapes, elongated streaks or circular  patches. Healthy turf
may persist in the center of blighted patches, producing rings of frog-eye symptoms. Leaf blades
may develop bleached white lesions that appear similar to dollar spot lesions. Fusarium  species
can be isolated from the lesions.
     In California, the disease typically occurs in the absence of foliar blighting. Patches appear
when foliage dies as a result of the  destruction of crowns and attached roots by  F. culmorum. The
pinkish mycelium of the pathogen can be seen on crown surfaces when soil moisture is high. Stem
bases  and crown tissues eventually develop a dark brown or black, firm rot.

     Currently, the name Fusarium blight is retained to describe foliar blight, crown rot and root rot
symptoms in situations where signs of Fusarium spp., such as spores and pink mycelial growth, are
abundant. Two additional diseases, described previously, are now recognized as summer patch
and necrotic ring spot, where Fusarium spp. are not  involved and roots bear dark-brown, runner
hyphae. The control measures for Fusarium blight are the same as those described for summer

     In summer, Kentucky bluegrass, fine leaf fescues and other grasses may decline due to
invasion  by IL sorpkiniana. This fungus also may cause a leaf spot and melting-out phase. JL
sprpkiniana is normally most severe when temperatures exceed 85F and humidity is high. This
disease is generally aggravated when turf is subjected to drought stress. Today, the fine leaf fescues
are frequently more severely damaged in summer by this fungus than Kentucky bluegrass. Again,
this is principally related to the development of resistant cultivars of Kentucky bluegrass; whereas,
highly resistant cultivars of fine leaf fescues are not yet available. Also during warm, dry periods EL
cynodontis may become a severe crown, stolon and root rot pathogen of bermudagrass. See the
"Helminthosporium and Melting-Out" section for management of melting-out.

     Fairy rings may be caused by any one of 60 or  more species of fungi. The activity of these
fungi in the thatch and soil results in rings  or arcs of dead or unthrifty turf, or rings of dark green,
luxuriantly growing grass. The most destructive  rings are classified as Type 1 rings. Type 1 rings
are very common,  especially in old pasture turfs or any mature turf with a lot of thatch. Type 1 rings
normally appear as circles or arcs of dark green, fast growing grass. The most common fungus
known to cause Type 1 fairy ring is Marasmius oreades. These rings are distinguished by three
distinct zones: an  inner/lush zone  where the grass is stimulated and grows luxuriantly; a middle
zone where the grass may be dead; and an  outer zone in which the grass is stimulated. The distance
from the inside of the inner zone ta the outside of the outer zone may range from a few inches to
one or more feet wide. The dead zone is due to a massive build-up in the thatch and soil of fungal
mycelium. It accumulates in such large amounts to form a hydrophobic barrier that prevents entry
of rain or irrigation water, thus killing the plants by drought. The formation  of the three zones is
noticeable from early spring to winter.
     Control of fairy rings is made extremely difficult due to the impermeable nature of the infested
soil. Chemical control has been ineffective because the fungus grows deeply  into the soil and lethal
concentrations of fungicide do not come into contact with the entire fungal body. Suppression is the
most practical approach to combating fairy rings in most situations. The suppression approach is
based upon the premise that fairy rings are less conspicuous and less numerous where turf is well
watered and fertilized. This method of control involves a combination of aeration, deep waterings
and proper fertilization. Aeration  is beneficial, as it aids in the penetration  of air and water. The
entire area occupied by the ring, to include a two foot periphery beyond the ring, should be core
aerified on two to four inch centers. The area should then be irrigated to a depth of four to six inches.
Use of a wetting agent should help improve water infiltration. The ring area should be retreated in
a similar fashion at the earliest indication of drought stress; that is repeat the  process whenever the
dark green grass turns blue-gray and begins to wilt. When an aerator is not  available, a deep root
feeder with garden hose attachment may be useful to force water into the dry soil. About 3.0 to 4.0

Ib N/1000 ft should be applied to cool season turfgrass species in three to four applications during
fall or late winter.
     There are two methods of eradication: fumigation and excavation. Both methods are laborious,
costly and not always successful. To fumigate, the sod must be removed from an area two feet to
the inside and at least two feet to the outside of the rings. It is essential not to spill any soil or sod
onto the healthy  grass. The most commonly  used fumigants are methyl bromide and metam.
Fumigation with methyl bromide must be carried out by a licensed pesticide applicator. Special
precautions must be taken  to insure that children or pets do not come into contact with these
fumigants.  The second alternative to fairy ring eradication Is to carefully dig out and discard all
infested soil in the ring. This would involve removal of soil to  a 12-inch depth, and the excavation
should be wide enough to extend at least two feet beyond the outer most evidence of the ring. The
excavation must then be filled with fresh, uncontaminated soil and the area reseeded or sodded.
Hence, the eradication approach for fairy ring control is impractical and seldom performed.
                                WINTER DISEASES

     Snow protects dormant  turfgrass plants from dessication and frost, but also provides a
microenvironment conducive to development of some low temperature, pathogenic fungi. Like
most other disease problems, there is no shortage of fungal species that are capable of damaging
turf during cold periods between late fall and early spring. The most common low temperature
fungal diseases are pink snow mold (Microdochium nivalis). and gray snow mold (Typhula incarnata
and T ishikarensis). Other diseases known to be active under snow cover or during winter months
include red thread (Laetisaria fuciformis) and leaf spot (Drechslera spp.). During cool moist periods
of late fall or early spring, cool temperature brown patch (Rhizoctonia cerealis) is a common disease
of putting green turf.
     Snow mold fungi are remarkable in being active at temperatures slightly above freezing. Snow
molds are damaging when turf is dormant or when growth of turf has been retarded  by low
temperatures. Under these conditions, turfgrasses cannot actively resist fungal invasion. Although
known as snow molds, these  fungi can attack turf with or without snow cover.  In general, these
diseases develop whenever temperatures are cool (32-60F) and there is an abundance of surface
     Conditions favoring pink snow mold include low to moderate temperatures; plenty of moisture;
prolonged deep snow;  snow fallen  on unfrozen  ground; lush turf stimulated by late season
application of excessive amounts of nitrogen fertilizer, and alkaline soil conditions.  Symptoms of
this disease appear as small water soaked patches two to three inches in diameter that may increase
in size to one to two feet in diameter and coalesce. The pink coloration of affected turf at the edge
of the  patches is produced by the pinkish color of the mycelium. The mycelium mats the  leaves,
and  plants eventually collapse  and  die. Mycelium on the leaf blades produce fruiting  bodies
(sporodochia) upon which spores are borne in prodigious numbers. These spores are easily spread
by machinery and foot traffic. When damage occurs under snow the extent of injury is usually more
severe than without snow cover. The pathogen, once known as Fusarium nivalef is able to  survive

unfavorable environmental conditions as spores and as resting mycelium that remain viable in plant

     Pink snow mold attacks a wide range of turfgrass species under snow including perennial
ryegrass, Kentucky  bluegrass,  bentgrass and  the  fescues.  This disease is generally  most
destructive to annual bluegrass and bentgrass. For many years the standard fungicidal control has
been phenyl mercury acetate or mercurous plus  mercuric chloride. The soluble  mercuric chloride
provides quick disease suppression and the insoluble mercurous chloride provides persistent
protection. Mercury-based fungicide may  only be applied to putting greens and tees, and only for
the purpose  of snow mold control.  Pentachloronitrobenzene (PCNB), benomyl, iprodione  and
triadimefon also provide good control. Fungicidal control is best achieved with a preventative
application prior to the first big snow storm of the year. Subsequent applications should be made
during mid-winter thaws and early spring snow melt in areas where the disease is a chronic problem.
     Gray snow mold, or Typhula blight, is also a  serious disease of turfgrasses as well as cereals
in North America and Europe. Initially, symptoms appear as light brown or gray patches two to four
inches in diameter enlarging to two feet in diameter and coalescing. Gray snow  mold also occurs
with and without snow cover; however, damage  is usually minimal in the absence of snow. Like
pink snow mold, Typhula blight is more damaging under prolonged deep snow,  particularly when
heavy snow accumulates on unfrozen ground.
     Gray snow mold initially begins its disease  cycle  as a saprophyte colonizing dead organic
matter. Under snow, however, the fungus moves onto living  leaves, sheaths and may ultimately
invade the crown. Normally, Typhula spp.  do not completely kill crowns so plants generally recover
during the spring. Conversely, pink snow mold more frequently invades crown tissues and kills turf.
Typhula  spp. survive unfavorable  environmental conditions as sclerotia. Sclerotia are compact
masses of fungal mycelium covered with a  dark colored, protective rind. Sclerotia are chestnut brown
or black in color and are less than 1/8 inch  in diameter. When cool, moist weathers conditions return
in late fall, these sclerotia germinate to produce fungal mycelium or a specialized fruiting body upon
which spores are borne. All species of Typhula that attack turf produce similar symptoms. Sclerotial
color is one of the primary characteristics pathologists use to differentiate between the two species
of Typhula known to cause gray snow mold.
     Gray snow mold, like pink snow mold, is  best controlled  using  a mercurial applied on  a
preventative schedule. Iprodione and triadimefon as well as cadmium based fungicides also provide
effective control of the disease. Cadmium (like mercury)-based fungicides, however, may only be
applied to golf course greens and tees.  Snow mold  prevention with fungicides is generally only
warranted for golf course turf in most regions of the U.S.
     Researchers in Canada have shown that the fungus Typhula  phacorrhiza applied on grain
inoculum suppressed gray snow mold on  creeping bentgrass greens by 44% to 70%. Although not
yet commercially available, these Canadian researchers believe that this biological control agent
can be formulated into pellets and be applied by standard fertilizer spreaders.
     Snow mold injury can be reduced by applying a balanced  N-P-K fertilizer in fall. Ammonium
sulfate use was associated with reduced  pink snow mold injury in Washington.  Continue to mow
late in the fall to insure that snow does not mat a tall canopy. On golf courses,  snow fences and
windbreaks should be used to prevent snow from drifting on chronically damaged greens. Avoid

compaction of snow by skiers and snow mobiles on greens. Also avoid the use of limestone where
soil pH is above 7.0, as alkalinity may encourage pink snow mold.
     Cool temperature brown patch, also known as yellow patch, is a disease of bentgrass, annual
bluegrass and perennial  ryegrass turf. It is most frequently observed on putting greens producing
rusty-brown  and yellow rings, or yellow patches a few inches to one or more feet in diameter.
Damage is generally superficial but significant thinning of turf may occur during prolonged, wet and
overcast weather of late winter and early spring. A broadspectrum fungicide such as anilazine,
chiorothalonii or iprodione will prevent severe thinning, but no fungicides or cultural practices are
known which help to prevent the formation of rings and patches.

     Arriving at the decision of whether to apply a fungicide to any turf area is often difficult and
 generally based upon economic considerations. Aside from cost, the primary determinants in using
 a fungicide are the prevailing environmental conditions, host species and cultivars present, and the
 pathogen. The environmental factor has unique implications in turf grass pathology because the
 intensity and nature  of turf grass management  greatly influences plant vigor and therefore  the
 incidence and intensity of diseases.
     Promoting vigorous growth through sound cultural practices is the first step in minimizing
 disease injury. Frequently, however, environmental stresses, traffic and poor management weaken
 plants, predisposing them to invasion by fungal pathogens. When disease symptoms appear, it is
 imperative that a rapid and accurate diagnosis of the disorder be made. The prudent manager also
 attempts to determine those  factors that have led to the development of the disease. The most
 common cause  for extensive disease injury in  lawn turf can  frequently  be related  to poor
 management practices by the homeowner. Abusive practices include frequent and close mowing;
 light and frequent irrigations; and inadequate or excessive nitrogen fertility. The development of
 excessive thatch layers, shade,  poor drainage and traffic also contribute significantly to disease
 problems. A good case in point is Helminthosporium diseases, which are particularly damaging
 when turf is mown too closely, given light and frequent irrigations, and  when turf is excessively
 fertilized. Despite hard work and adherence to sound management practices,  diseases often
 become  a serious problem. This normally occurs when environmental conditions favor disease
 development, but not plant growth and vigor. For example, summer patch and brown patch  are
 most damaging  when high  summer temperatures stress plants and  impair their growth and
 recuperative capacity. In this situation, fungicides may be recommended in conjunction with cultural
 practices that promote turf vigor.
     Fungicides may be applied  preventatively (i.e.  before anticipated disease symptoms appear)
 or curatively (i.e. when disease symptoms first become evident). Applying a fungicide after the turf
 has been damaged significantly is generally a waste of time, money and effort. Curative applications
 are more economical and environmentally wise, but only if the disease can be treated rapidly. In
 general, a single or possibly two, properly timed applications will provide effective control of most
 disease problems encountered on home lawns. Contact fungicides are less expensive and provide
 good control. Contact fungicides,  however, may only provide 7-14 days of control under high disease
 pressure conditions. Where sudden  and severe, or chronic disease  problems  occur, a systemic
 alone, or a systemic plus contact  may be needed. Systemic or local systemic fungicides will provide

14-21 days protection during high pressure disease periods. Tank mixing a systemic plus a contact
fungicide provides a longer residual effect and a wider spectrum of control. Frequently, a fungicide
may only be needed to help the  turf better survive a high pressure disease period. Favorable
changes in weather such as alternating hot-humid and cooler periods, however, provide the most
effective means of reducing or eliminating disease problems in the summer.


     Proper utilization  and  selection of fungicides  is too difficult  and complicated for most
homeowners. Because of this, only lawn care companies can provide the most reliable lawn disease
service. Fungicides,  however, should not become a part of a normal application  schedule. As a
general rule, use of fungicides is not encouraged in most home lawn situations because (a)  proper
diagnosis and proper fungicide selection is difficult, (b) it is generally too late to achieve the economic
and aesthetic benefits of a fungicide once extensive injury has occurred, (c) lawn care companies
capable of only dry or granular applications do not have the proper spray equipment or they cannot
obtain the desired fungicide(s) in granular form, and (d) it may be less expensive, and better in the
long run, to overseed a damaged turf area in the autumn with disease-resistant cultivars.
     There are several disease situations of lawn turf that are best controlled through a preventative
fungicide application. These disease situations are: (1) Kentucky bluegrass lawns injured in previous
years  by summer patch, necrotic ring  spot, stripe  smut and perhaps dollar spot, (2) perennial
ryegrass lawns injured in previous years by  Pythium blight, brown patch or dollar spot, and  (3) tall
fescue lawns  chronically  damaged by  brown patch. Many  diseases, however, are effectively
controlled with curative fungicide applications when disease symptoms first appear. For example,
leaf spot in lawns of common-type  Kentucky bluegrasses (e.g., Kenblue, Newport, Park,  South
Dakota, etc.) and fine leaf fescue (e.g., Pennlawn and Jamestown), and brown patch in perennial
ryegrass can be effectively controlled with a curative fungicide application. Dollar spot disease  is
extremely common and  if allowed to go unchecked, may cause extensive injury to Kentucky
bluegrass,  perennial ryegrass,  red fescue and zoysiagrass lawns. When diagnosed  in its early
stages, however, dollar spot is also effectively controlled by fungicides. Given these situations, it
becomes obvious that effective fungicide programs hinge upon (a)  knowledge of past disease
problems in a particular lawn or neighborhood, (b) ability to distinguish between turfgrass species
and sometimes cultivars within a species, and (c) ability to diagnose turfgrass diseases. Hence,  in
addition  to the expense of fungicides and logistical problems associated with sending trucks  to
specialized  fungicide accounts, the lawn care company must also educate  its employees  to
diagnose diseases. This educational process is best achieved by in-house training programs. This
knowledge must be reinforced by encouraging employees to attend turf workshops and conferences
held by state universities and other organizations, as well as maintaining subscriptions and reading
articles in trade magazines. Expecting the employee to be proficient by reading alone is not realistic,
even for highly motivated individuals.
     In Table 2, the most common lawn diseases are listed, as  well as their primary season(s)  of
occurrence, and those species that are most commonly damaged. Remember, once a disease has
severely reduced stand density, fall overseeding with resistant cultivars  is normally suggested.
Fact sheets describing the disease and a list of cultural practices that will help minimize disease
injury should be provided by the lawn care company to homeowners.


     Where extremely high quality turf is desired, fungicides will be needed in most years, and in
nearly all areas of the U.S.  The indiscriminate use of fungicides or employment of numerous,
preventative applications of  fungicides  for many diseases should  be discouraged.  Other than
economic restraints, reasons why repeated fungicide applications may not be desirable include:
1.  Fungicides may reduce the population of beneficial microorganisms in the  soil, which could
    lead to excessive thatch build-ups.
2.  Fungicides may disturb  a delicate  balance among microorganisms that compete  with and
    antagonize disease-causing fungi. This may explain why some diseases recur more rapidly
    and cause more injury in turfs previously treated with fungicides.
3.  A fungicide may control one disease, but encourage other diseases.

     When used repeatedly, certain fungicides have been shown to enhance thatch accumulation.
Benzimidazole fungicides, such as benomyl and the thiophanates, and sulfur-containing fungicides
such as mancozeb, maneb and thiram can cause thatch to accumulate by acidifying soil. The effect
of these fungicides is  indirect, that is they inhibit the thatch decomposition capacity of beneficial
microorganisms by lowering soil pH. Cadmium fungicides and iprodione also may enhance thatch
accumulation.  In the case of these latter two compounds, thatch build-up is attributed to direct
toxicity of microorganisms that degrade  thatch. Fungicides  may also contribute to thatch build-up
by being toxic to earthworms. Earthworms help reduce  thatch by mixing soil with organic matter.
Benomyl, mancozeb, anilazine, chlorothalonil and various nematicides have been shown to be toxic
to earthworms.
     Turf managers have observed that some diseases may recur more rapidly and severely in turfs
previously treated with fungicides, as compared to adjacent untreated areas. Dollar spot is probably
the most common disease to exhibit this phenomenon. Data, recorded in a Maryland study, showed
that red thread was more severe in the spring of 1983 in Manhattan perennial ryegrass  plots last
treated with benomyl  in July,  1982. These phenomena are attributed to  non-target effects of
fungicides, i.e., the fungicide(s) were toxic to microorganisms which antagonize and help keep
disease-causing fungi in abeyance.
     The development of fungal strains resistant to fungicides has been well documented. Resistant
strains of the dollar spot fungus first developed as a result  of repeated usage of cadmium based
fungicides and benomyl on golf courses. Thiophanates, anilazine, and iprodione resistant strains
of the dollar spot fungus have  also been reported. The development of resistant strains of fungi
likely occurs in response to  a selection process  that  eventually enables a small, but naturally
occurring  population of resistant biotypes to  predominate in the fungicide-treated  turf grass
microenvironment. It is very unlikely, however, that occasional fungicide use on home lawns would
lead to the development of fungicide-resistant biotypes.
     Fungicides applied to control one disease may encourage other diseases. As previously noted,
benomyl can encourage red thread. Benomyl has also been shown to enhance Helminthosporium
leaf spot and Pythium blight. Thiophanate-methyl may increase crown rust in perennial  ryegrass,
iprodione can increase yellow tuft, and maneb may enhance  dollar spot. Encouragement of disease

in these situations may again be attributed to offsetting the delicate balance between antagonistic
and pathogenic microorganisms in the ecosystem.

     The phytotoxicity that accompanies the usage of some fungicides is generally  not severe.
Most phytotoxicity problems occur when fungicides are applied to bentgrasses, particularly during
periods of high temperature stress. Repeated applications of sterol-inhibiting fungicides such as
fenarimol, propiconazole or triadimefon may elicit a blue-green color in foliage of creeping bentgrass
and other turf grass species.

     It should  be noted that many  of the harmful side effects just described were either isolated
events or occurred only  after repeated use of  one fungicide over the course of several years.
Experienced turfgrass managers have long recognized that tank mixing fungicides and rotating
fungicides greatly minimizes these potential problems.  The importance of rapid  and accurate
disease diagnosis, and the judicious use of fungicides are integral in management programs where
fungicides are commonly employed.

     Nematodes  are known to cause extensive  injury  to  turfgrasses in warm temperate and
sub-tropical areas in the  U.S. In northern climates, the loss of turfgrass that can be attributed to
nematodes is unknown. However, nematodes may be more troublesome in the transition zone and
Mid-Atlantic area than is commonly believed. This would be particularly true following a  mild winter.
In general, nematodes most actively feed on turfgrass during environmental periods favorable for
growth of the grass. Hence, feeding would be more active on cool season species in spring and
fall,  while on warm season  grasses heaviest feeding would occur during summer. The injurious
effects of this feeding, however, may not become noticeable until turf is subjected to environmental
stresses in mid-to late summer.
     Nematodes are very small eel-like worms, ranging from  1/50 to 1/8 inch in length.  Nematodes
reproduce by eggs, which hatch to liberate larvae. Larvae molt four times before reaching adult size.
Each female is capable of producing hundreds of eggs and the entire life cycle is completed in five
to six weeks under suitable conditions for most species. Because plant pathogenic nematodes are
obligate parasites, they must feed on living tissues in order to grow and reproduce. Most nematodes
are capable of attacking a wide range of plant species, and can survive on weeds in the absence
of turfgrasses. Most nematodes store large quantities of food, which enables them to survive long
periods in soil in the absence of suitable plants. Many also survive in frozen soils and may overwinter
in living roots or in dead plant tissues.
     Literally millions of nematodes can  inhabit a few square feet of soil, but most nematodes are
non-pathogenic. Some non-pathogens, may actually perform a beneficial service in soil by helping
to degrade organic matter. Although there are thousands of species, only about 50 species are
known to parasitize turfgrasses. All plant parasitic nematodes bear a hollow,  spear-like structure
called a stylet. The stylet is similar to a hypodermic syringe, and is used to inject enzymes into plant
cells. Simultaneously, partially digested food is withdrawn.  Plant pathogenic nematodes are grouped
according to feeding habit. Endoparasitic nematodes partially or totally burrow into plant tissues
and  feed primarily within; whereas,  ectoparasitic nematodes  feed from the plant surface, although
a small portion of the body may be embedded. The ectoparasitic are more commonly injurious to
turfgrasses than endoparasitic nematodes. Nematode activity is favored by warm and moist soil
conditions. Nematode populations generally peak in June or July and again in late August or early

September. Their activity is also enhanced in light textured soils and reduced in compacted or heavy
soils where aeration becomes restricted. Nematodes are unable to move more than a few millimeters
in soil, but they may be transported over larger distances by moving water and soil.
     The symptoms of nematode injury include yellowing, stunting, wilting or early signs of drought
stress, and thinning of the stand. These symptoms are related to the injury nematodes inflict upon
the root system. Therefore, symptoms of injury may not become noticeable until water becomes
limiting. Due to the similarities between environmental stress symptoms and nematode injury, the
source of the problem is difficult to diagnose.  Like many so-called weak or secondary fungal
pathogens, nematodes may not cause much of a problem until environmental extremes reduce the
vigor of a turf. There is often no pattern to nematode injury, but generally affected areas may appear
in streaks or oval-shaped areas. Severe infestations may result in a nearly total loss of grass plants,
which are soon replaced by weed species. Inspection of roots may or may not reveal some indication
of nematode feeding. Roots  may exhibit one or more of the following symptoms: swellings, red or
brown lesions, excessive root branching, necrotic root tips and root rot. Some of the more common
plant parasitic nematodes, which are known to injure turfgrasses, are listed in Table 3.
     Turfgrass areas damaged by nematodes do not respond readily to an application of fertilizer
or fungicides. This lack of response may be a good indicator of a nematode problem. In this situation
a soil sample should be sent to a nematologist for analysis. Soil should be collected from a dozen
or more areas at the edge or interface between healthy and injured turf. Sampling from severely
thinned areas may yield unreliable results, because these obligate parasites will not survive in large
populations in the absence of living plants. Soil samples should also be collected in the root zone
region, normally the upper three to six  inches in heavy soils, but six to twelve inches or deeper in
sandy soils. The samples should be combined, as in a routine soil-fertility sample, and at least a
pint of soil is needed. Samples should also  be  taken from nearby,  healthy turf  so  that  the
nematologist can compare numbers and species of nematodes between the two areas. The soil
must be kept moist and given to the nematologist as soon as possible. Refrigerate the sample, but
do not freeze it, if there will be a delay in transport to the lab. In the  laboratory, various methods for
extraction are used. Unfortunately, there are no reliable data correlating nematode  number  per
sample and expected degree of turf injury in the field. The nematologist, however, will generally be
able to make a relatively good management recommendation based on species and number of
nematodes present in a sample.
     An absolute determination of a nematode problem from visual symptoms and even soil analysis
is difficult. Frequently, the best indication of a  nematode problem is a positive response from a
nematicide. It should  be  pointed  out,  however, that turf green-up invariably occurs following a
nematicide application, presumably because  of  the  death of  nematodes as well  as  other
invertebrates which  liberate nitrogen upon decay. Nematicides are highly toxic, organophosphate
derivatives. They must be handled with extreme caution and used only according to the procedure
and at the rates given on  the label. Because the target of a nematicide is in soil, it is essential the
chemical be thoroughly watered-in, and aerification prior to application will facilitate the downward
movement of the chemical. Ethoprop is the only nematicide registered for use on home lawns, but
it must be applied by a certified pesticide applicator. Other nematicides  include fenamiphos and
fensulfothion. All three are available in granular form. Fumigants are of little practical value because
they kill turf as well as all other living organisms they come into contact with. Obviously, fumigants
would only be used prior to establishing a turf or if total renovation is desired.

     Because nematodes may only be injurious in northern regions during summer stress periods,
cultural practices that alleviate stress  may  help minimize injury. Such practices would include
judicious irrigation, increasing the mowing height, and use of a balanced fertilizer. Application of
soluble nitrogen fertilizer during environmental stress periods of summer will place an additional
(and perhaps lethal) stress on an already dysfunctioning root system under attack from nematodes.
There are some research data indicating that use of organic forms of nitrogen fertilizer (e.g. sewage
sludges) can discourage development of high populations of some parasitic nematodes, when
compared to the use of inorganic forms. Currently,  researchers are evaluating a dried,  granular
chitin-protein material called Clandosan, which is obtained from crab and shrimp shells, for control
of nematodes. The mode  of action of  Clandosan  presumably is  to  stimulate growth of soil
microorganisms that produce enzymes such as chitinase. These enzymes also degrade the cuticles
and eggs of plant parasitic nematodes, thereby providing an indirect, biological means of nematode
control. To date, however, there is insufficient data and information regarding the effectiveness of
Clandosan in turf.

Burpee, L.L., L.M. Kaye, L.G. Goutty and M.B. Lawton. 1987. Suppression of gray snow mold on creeping bentgrass by
        an isolate of Typhula phacorrhiza. Plant Disease 71:97-100.
Dernoeden,  P.M., J.J. Murray  and N.R. O'Neill.  1985. Non-target  effects  of fungicides on turfgrass growth  and
        enhancement of red thread, pp 579-593 Jn F. Lemaire (ed.) Proc. Rfth Intern. Turf. Res. Conf. Avignon, France.
Smiley, R.W. 1983. Compendium of Turfgrass Diseases. American Phytopathological Society, St. Paul, MN.
Smiley, R.W. 1981. Non-target effects of pesticides on turfgrasses. Plant Disease 65:17-23.
Smiley, R.W. and M.M. Craven. 1978. Fungicides  in Kentucky bluegrass turf: Effect on thatch and pH. Agron. J.
Smiley, R.W. M.C. Fowler, R.T.  Kane, A.M. Petrovic and R.A. White.  1985. Fungicide effects on thatch depth, thatch
        decomposition rate, and growth of Kentucky bluegrass. Agron. J. 77:597-602.
Vargas, J.M. 1981. Management of Turfgrass Diseases. Burgess Publishing Co. Minneapolis, MN.

                                               TABLE 1
The most frequently encountered diseases of lawns, golf courses, athletic fields, and other turf areas
in transition zone and northern regions of the U.S.
Primary Hosts
        Summer Patch                 ABG, FLF, KBG
        Necrotic Ring Spot
        Take-All Patch

        Spring Dead Spot
        Dollar Spot
        Red Thread
        Pink Patch
        Brown Patch
        Leaf Spot
        Gray Snow Mold

        Cool Temperature Brown Patch
        (Yellow Patch)
        Gray Leaf Spot
        White Blight

All species except TF
Most species
All species
All species

St. Augustine
        Pythium Blight                 ABG- CBG- PRG
        Pink Snow Mold
All species
Magnaporthe poae
Leptosphaeria korrae
Gaeumannomyces graminis var.
Leptosphaeria korrae
Sderotinia homoeocarpa
Laetisan'a fuciformis
Umonomyces roseipellis
Rhizoctonia solani
Drechslera or Bipolaris spp.
Typhula  incarnata  and
Rhizoctonia cerealis
Pyricularia grisea
Melanotus phillipsii
Pythium aphanidermatum, £.,
Microdochium nivalis
Colletotrichum araminicola

Primary Hosts
         Pythium Induced Root Dysfunction   ABG, CBG
         Nematodes                     Most species
         Melting-out                     KBG- FLF- PRG
         Fusarium Blight
Pythium spp.
Many species
Drechslera or Bipolaris spp.
Fusarium culmorum and F. poae
         Stripe Smut
         Flag Smut
         Powdery Mildew
         Yellow Tuft
KBG in shade
PEG, KBG, Zoysia
All species
Ustilago striiformis
Urocystis agropyri
Erysiphe graminis
Puccinia spp.
Sderophthora macrospora
         Fairy Ring
         Yellow Ring
         Superficial Fairy Ring
         Localized Dry Spot
All species
Putting greens
Putting greens
Many Basidiomycetes
Trechispora alnicola
Unknown Basidiomycetes
 Hosts:   ABG = annual bluegrass
         KBG = Kentucky bluegrass
         CBG = creeping bentgrass
         PGR = perennial ryegrass
         FLF = fine leaf fescue
         TF = tall fescue
All species
Pythium spp.
Fusarium spp.
Rhizoctonia solani
Bipolaris spp.
Drechslera spp.
Curvularia spp.

                                                TABLE 2
      Common  diseases of transition zone  and northern  lawn grasses,  the  primary season of
occurrence, and the primary grasses most likely to be damaged.
       Primary Season
       of Occurrence
   Lawn Grasses Damaged
        Helminthosporium  Leaf  Spot,   Spring and Fall Summer
        Melting-out and Net-blotch
        Red Thread

        Necrotic Ring Spot
        Dollar Spot
Spring and Fall

Early Spring to Early Winter
Early Spring to Early Winter
        Brown Patch                   June, July, August
        Summer  Patch and  Fusarium  June, July, August
        Pythium Blight
        Stripe Smut
         Powdery Mildew

         Fairy Rings
June, July, August
Spring and Fall
Spring and Fall

Spring and Fall

Spring to Early Winter
Common-type Kentucky bluegrass,
Fine leaf  fescues,  Perennial
Perennial  ryegrass,  Fine  leaf
fescues, Kentucky bluegrass
Kentucky bluegrass
Perennial  ryegrass,  Kentucky
bluegrass, Fine leaf fescues
Perennial ryegrass, Tall fescue
Kentucky bluegrass,  Fine  leaf
Perennial ryegrass
Kentucky bluegrass
Perennial  ryegrass,  Kentucky
bluegrass, Zoysiagrass
Kentucky bluegrass,  Fine  leaf
All species

                                                   TABLE 3
      Common plant pathogenic nematodes known to be injurious to turfgrasses.
           Nematode Common name/
        Feeding group
    Turfgrasses injured/root
         (Pratylenchus spp.)
         (Hoplolaimus spp.)
         (Macroposthonia spp.)
         (Helicotylenchus spp.)
         Stunt or stylet
         (Tylenchorhynchus spp.)

         (Meloidogne spp.)


         Stubby root
         (Trichodorus spp.)
         (Belonalaimus spp.)
         (Xiphinema spp.)
         (Paratylenchus spp.)
Cool and warm season grasses
are injured. Root lesions initially
minute and  brown,  but enlarge
and may prune the root system.
Warm season grasses and annual
bluegrass  are  injured. Causes
swelling  of  roots  followed  by
necrosis and sloughing of cortical
Especially    important    in
centepedegrass, also injured are
Kentucky bluegrass,  bentgrass,
bermudagrass, and zoysiagrass.
Roots are stunted; produces brown
lesions on roots.
Cool and warm season grasses
injured. Roots are poorly developed
with premature sloughing of cortical
Warm and cool season grasses
injured. Roots shortened, shriveled,
brown; no lesions evident on roots.
Warm   season   (especially
zoysiagrass)  and  cool season
grasses  (especially  bentgrass)
injured.  Galls  (i.e.  swellings or
knots) on roots. Galls may  be
small and difficult to see.
Warm season grasses, Kentucky
bluegrass and tall fescue injured.
Large brown lesions  on  roots;
swelling of root tips.
Bermudagrass,  zoysiagrass  and
St.  Augustinegrass are injured.
Lesions  evident, especially  root
Warm season grasses (especially
zoysiagrass)   and  perennial
ryegrass are injured. Root lesions
are reddish brown to black  and
Kentucky bluegrass, fine and tall
fescues are injured. Tillering and
rooting increased, but fewer lateral
roots. Distinct lesions on roots.

                                 TABLE 4
Trade    Common Chemical
Name*    	Name	

Mocap    ethoprop
Nemacur  fenamiphos
Dasanit  fensulfothion
Nematicidal Rate

2.3 Ib. of 10B/
1000 ft2 or 100
2.3 - 4.6 Ib of
10B/1000 ft2 or
1.5 - 3.0 Ib of
15G/1000 ft2 or
68-134 Ib/A
Only the 10G formulation is
registered for use on bahia,
bermuda, centipede, fescue,
Kentucky bluegrass, St.
Augustine and zoysia grass
turfs, labelled for control
of dagger, lance, lesion,
ring, root-knot, spiral
sting, stubby root, stunt,
and other nematodes.  May
be used at lower rates to
control some insects,   use
on established turfs only.
Can be used on home lawns
by a certified applicator.

Only the 10G formulation is
registered for use on ber-
muda, 100-200 Ib 16/A.
centipede, bluegrass and
bentgrass turf.  Do not
use on residential lawns
or public recreation
areas other than golf
courses.  Do not use on
newly seeded areas and do
not apply more than twice
per year.  Turf should
not be cut for sod for 21
days after treatment.

Only the 15G formulation is
registered for use on com-
mercial (i.e., sod farms,
golf courses, cemeteries)
turf grasses.  Turf should
not be cut for sod for 30
days after treatment.
May be used for control
of white grubs.
* Nematicides may only be applied by commercial or professional certified
  pesticide applicators.

 Burpee, L.L., LM. Kaye, L.G. Goulty and M.B. Lawton. 1987. Suppression of gray snow mold on creeping bentgrass by
        an isolate of Typhula phacorrhiza. Plant Disease 71:97-100.
 Dernoeden,  P.H., J.J. Murray and N.R. O'Neill.  1985.  Non-target effects of fungicides on turfgrass growth and
        enhancement of red thread, pp 579-593 Jn F. Lemaire (ed.) Proc. Fifth Intern. Turf. Res. Conf. Avignon, France.
 Smiley, R.W. 1983. Compendium of Turfgrass Diseases. American Phytopathological Society, St. Paul, MN.
 Smiley, R.W. 1981. Non-target  effects of pesticides on turfgrasses. Plant Disease 65:17-23.
 Smiley, R.W. and M.M.  Craven.  1978.  Fungicides in  Kentucky bluegrass turf: Effect on thatch  and pH. Agron. J.
 Smiley, R.W. M.C. Fowler, R.T. Kane,  A.M.  Petrovic and R.A. White. 1985. Fungicide effects on thatch depth, thatch
        decomposition rate, and growth of Kentucky bluegrass. Agron. J. 77:597-602.
 Vargas, J.M. 1981. Management of Turfgrass Diseases. Burgess Publishing Co. Minneapolis, MN.


                                   Michael G. Klein
                       Horticultural Insects Research Laboratory
                         Application Technology Research Unit
                         USDA - Agricultural Research Service
                  Ohio Agricultural Research and Development Center
                                 Wooster, Ohio 44691
    The term white grubs, as used here, refers to larvae of beetles in the family Scarabaeidae.
Tashiro (1987) notes that there are 10 species of grubs in five subfamilies that are pests of turfgrass
in the United States. Scarab grubs are the most serious pests of turfgrass in the Northeast, major
pests throughout the Midwest (Tashiro 1987), and of increasing importance in warm season turf
(Cobb 1988). Both introduced and native Scarabs are turfgrass pests. Grubs in two native genera,
Cyclocephala and Phyliophaga. cause problems in almost all  areas of  the country. Introduced
species are most prevalent in the Northeast, where the Japanese beetle, Popillia japonica Newman,
the European chafer, Rhizotrogus majalis (Razoumowsky), the oriental beetle, Anomala orientalis
Waterhouse, and the Asiatic garden beetle, Maladera castanea (Arrow), in that order, all are pests
in the urban environment (Tashiro 1987).
    The Japanese beetle is the most serious turf pest in the United States (Tashiro 1987). Fleming
(1972) reported that 22 states east of the Mississippi River, and Iowa and Missouri to the west, had
Japanese beetle infestations in 1972. Since that time, beetles have moved  into Alabama, and within
one county of the Florida border (Hall 1987).  In addition, isolated infestations of beetles have been
found in Wisconsin, Oregon, and twice in California (both eradicated). Ahmad  et al. (1983) estimated
the losses caused by Japanese larvae to be  240 million dollars per year. This included $78 million
for control costs and an additional $156 million for replacement of damaged turf. Unlike most of the
white  grub complex, the adults of the Japanese beetle are also serious pests. Fleming (1972) lists
almost 300 plants fed on by the beetles. New additions to this list will be made as beetles move into
new areas and as their feeding behavior is further studied. It is estimated that damage and control
costs  are at least as great for the adults as that reported for larvae.
    Fleming (1976) summarized the components available for control of the Japanese beetle in
1976. This included a variety of both chemical and biological agents. However there has been little
effort  at a truly integrated program of suppression against the Japanese beetle or other white grub
species. Recently, states such as Massachusetts (Vittum 1987) and Maryland (Hellman 1988) have
developed turf and ornamental IPM efforts. Vittum (1988) states that "several standard insecticides
give acceptable levels of control for most grub species". However, concerns about grub control and
environmental safety persist. Villani et al.  (1988) note  that the organophosphate and carbamate
insecticides now in use are less effective than materials previously available. Factors as diverse
as insect resistance, microbial degradation of insecticides, the importance of pH and moisture, and
the  role of the thatch or organic matter in preventing movement of the insecticides  to the target
organisms have been reported by several authors as explanations for the reduction in insecticide
effectiveness (Villani et al. 1988, Niemczykand Chapman 1987, Niemczyk 1980). In addition, there

is an increasing concern about the fate of insecticides in the environment and the potential of
pesticide runoff causing water contamination (November 1988, Watschke et al. 1988). All of the
above factors make the use of biological agents in the suppression of turf insects more attractive.
I  will examine the biologicals that are available and access their place in suppression programs.


     Several recent reviews and books examine the role  of microorganisms in pest management
(Surges 1981, Samson et al. 1986, Fuxa 1987, Fuxa and  Tanada 1987). Fleming (1968) reviewed
the history and status of biological control of the  Japanese beetle up to 1968. In addition, Klein
(1982, 1988) reported on the state  of  biological  suppression of turf insects  in 1982, and  pest
management of all soil-inhabiting insects with microorganisms in 1988. These sources will give the
reader additional details on  those subjects. Bacteria are the  most important microorganisms
available for biological suppression of white grubs.  Protozoa and fungi  are important natural
microorganisms in regulating grub populations, but neither is commercially available at the present
time (Klein 1988a).
Milky Disease Bacteria

     The value of Bacillus popilliae Dutky and its role in  the regulation  of white grubs has been
examined in several recent book chapters (Klein 1988a, 1981a). This bacterium, EL popilliae. has
been used in the suppression of the Japanese beetle  for over 50 years  (Fleming 1968), and  was
the first microbial insecticide  registered in the United  States. When the bacteria develop in the
hemolymph of Japanese beetle larvae, they produce  billions of refractile spores and parasporal
bodies thus turning the  infected grub a milky white and giving rise to the common name of the
disease (Fleming  1968). Between 1939 and 1951, Federal and  State agencies produced  and
distributed about 90 tons of spore  powder at 132,299 sites in 15 different eastern states (Fleming
1968). At the present time, there are three commercial  brands of milky disease products available.
Doom(R)  and Japidemic(R)  are manufactured as a powder containing  100 million spores/g by
Fairfax  Biological  Laboratories, Clinton Corners,  NY.  Reuter Laboratories, Manassas Park, VA
produces  a powder and granular  formulation under the brand name Grub  AttackTM.  For many
years, milky disease products were made by collecting  Japanese beetle  larvae from the field,
injecting them  with IL popilliae. and  harvesting spores from infected larvae (Fleming 1968).
However,  more recently, Fairfax has been collecting naturally infected Japanese beetle larvae in
the field (Chittick 1987), and Reuter Laboratories intends to produce the bacteria in artificial media
(Obenchain 1988).
     An application rate of 10 Ib/acre is recommended by both manufacturers. This is normally
accomplished by placing about 2 g of spore powder in  spots in a grid on four foot intervals. When
large areas of  turf are to be treated, a reduced rate of 2 Ib/acre (10  foot intervals)  has been
registered. Community wide treatment programs have been the most successful in reducing larval
damage and adult populations  (Fleming 1968,  Fleming and Ladd 1979, Ladd and Klein 1982).
However, since the milky disease  bacteria spread naturally in the field (Fleming 1968), it can be
beneficial to treat only a portion of the beetle infested area. Application of spore powder to portions
of two fairways of a Northeastern Ohio golf course  resulted in the finding of milky larvae throughout
the course after two years (Klein 1978). Several  years can elapse between application of milky
disease bacteria, and suppression  of Japanese beetle  populations (Fleming and Ladd 1979, Ladd

and Klein 1982). The disease builds up and spreads as larvae ingest spores, become infected, die,
and release 1-2 billion spores back into the soil (Fleming 1968). Although one might expect that the
use of the granular material distributed over the whole area would speed up the larval suppression,
that may not be the case. Even though the broadcast treatment uses twice as many spores per
acre (Klein  1982) as the spot treatment, the spores may be spread so thinly that the larvae do not
become infected more quickly.

     Soil temperatures may have a greater impact on larval suppression by milky disease bacteria
than does the  application method (Klein 1988a,  1981a). Although temperatures of at least 16° C.
are necessary for  development of the disease, temperatures of 21° C. are required for optimal
development (Fleming 1968, Fleming and Ladd 1979). Concerns about low soil temperatures have
 caused State personnel in several New England states question the value of milky disease bacteria
in their areas.  It should  be noted however, that  Fairfax Biological Laboratory obtains its naturally
infected milky grubs in these same areas (Chittick 1987) so the disease is working to some degree.
Daar (1988) has recommended quadrupling the dosage in areas above latitude 40° to speed up
development of the disease.  More information is needed about the role of milky disease  in the
northern ranges of the Japanese beetle. It is also possible that if B. popilliae can be grown on artificial
media that strains  could be isolated that will be effective at lower temperatures. There is also a
concern about the  persistence of EL popilliae spores in the environment (Klein  1988a). Although
spores are  clearly present in soil that was last treated 25-30 years previously, it is not clear if that
is due to persistence or periodic replenishment as subsequent larvae become infected and die.
     Production of EL popilliae on artificial media may also help to expand the host range of
commercial products to other white grubs. Although Grub Attack is listed as being effective  on
certain May and June beetles, oriental beetle, and  rose chafer in addition to Japanese beetle,
numerous studies  indicate that each species is  most susceptible to its own strain of EL popilliae
(Fleming 1968, Klein 1981a, 1982, 1986,  1988). Masked chafers (Cyclocephala spp.) are serious
turf pests nation wide, but are not infected by the commercial milky disease  formulations  (Klein
1981a, Warren  and Potter 1983). EL popilliae infections are credited with holding Cyclocephala
paraliela Casey to sub-economic levels  in Florida sugarcane fields (Boucias et al. 1986).  Since
Cyclocephala strains of  EL popilliae have grown on  artificial media (Obenchain 1989), it may be
possible to  produce a product  for masked chafers. However, the costs in registering such a product
may not be supported by the potential  market.  In addition,  although it is common to find high
incidences  of natural milky disease in Cyclocephala larvae in turf areas, the true value of the disease
in population suppression  has not been assessed. I have seen repeated turf damage in an area
following 50+% milky larvae the previous fall. The  black turfgrass ataenius,  Ataenius spretulus
(Haldeman) is another potential target for a milky disease product produced on artificial media.
These larvae have several strains of milky disease bacteria that build-up too late in the season to
have the full impact on the population (Tashiro 1987, Klein  1981a). Introduction of the spores into
the population  earlier in the season may improve the  situation.
     Concerns about the attenuation of EL popilliae spores in Connecticut are still being expressed
(Hanula and Andreadis 1988). Although Tashiro (in 23) found in the laboratory that about 75% of
larvae became infected when  placed in soil from Connecticut, Hanula and Andreadis (1988) noted
an incidence of only 3.5% milky larvae during extensive field surveys.

Other Bacteria

     Bacillus thuringiensis Berliner is the most widely used microorganism in commercial production
(Klein 1988a). Although it makes up at least 90% of the bioinsecticides on the market, it still makes
up less than 1% of the $13 billion pesticide market. EL thuringiensis products have been  used
primarily against lepidopteran pests of forests and ornamentals. Strains of IL thurinaiensiswith
activity against Coleoptera have  been isolated (Klein 1988a) giving rise to suggestions of using
them against the Japanese  beetle (Bio  Integral Resource Center 1987). However, recent  tests
have shown that the coleopteran  strains have no activity against either Japanese beetle larvae or
adults (Klein 1988b). It may be possible to isolate or create strains with activity against the Japanese
beetle or other Scarab adults. However, because of the short persistence of EL thuringiensis activity
in a soil environment  ((West et al. 1984) it is unlikely that it will be an important microorganism
against the white grubs in the near future.
     Bacteria in the genus  Serratia  have been associated with a disease of the grass grub,
Costelytra zealandica  (White) in New Zealand (Jackson et al. 1986). The bacteria cause the grubs
to turn an amber or honey color by colonizing the gut, resulting in the starvation of the larvae and
depletion of the fat bodies. Commercial production of the bacteria is moving forward in New Zealand
(Jackson 1988). Similar honey colored Japanese beetle larvae have been observed in the United
States, and Serratia species have been isolated from them (Jackson 1988). The potential exists to
develop certain Serratia species for control of white grubs in the future.
Other Microorganisms

     In addition to the bacteria, fungi and protozoa influence white grub populations. There are no
commercial fungal preparations available for use against Scarab beetles or larvae. Species of
Beauveria and Metarhizium are associated with  insect mortality world wide (Klein 1988a), and have
been isolated from  dead white grubs in this country (Tashiro  1987, Fleming 1968, Hanula and
Andreadis 1988). Work in Europe with the cockchafer. Melolantha melolantha (L.)r has shown that
a Beauveria species is effective when applied to the soil or to swarming females (Keller 1986). We
have a great deal to  learn about the potential of fungi to aid in  the suppression of white  grub
     Several genera of protozoa, in particular Nosema and Adelina. have been isolated from Scarab
larvae (Fleming  1968, Hanula and Andreadis 1988). Very little  is known about the true effects of
these protozoa on white grub populations, and they are often overlooked. Recently a new protozoan
has  been described from the Japanese beetle in  Connecticut  (Hanula and Andreadis 1988,
Andreadis and Hanula 1987). Ovavesicula popilliae Andreadis and Hanula was found infecting up
to 90% of Japanese beetle larvae locations (Hanula and Andreadis 1988). This microorganism has
the potential to be more fully utilized in the suppression of the Japanese beetle in the Eastern United


     The vast majority of work on attractants for Scarab species has been done with the Japanese
beetle. Fleming (1969) has summarized the work on Japanese beetle attractants from shortly after
the discovery of  the beetle in New Jersey in  1916 up to 1969. Although chemical attractants have

been noted for several other Scarab beetles, none have been developed commercially. Black lights
are available to attract several night flying beetles.
Japanese Beetle Attractants

    At the present time, seven companies are producing Japanese beetle traps and lures. The
best lure is a combination of the synthetic female sex attractant, Japonilure, (Tumlinson et al. 1977)
and three sweet smelling floral or food type lures: phenethyl propionate, eugenol, and geraniol in a
3:7:3 combination (Ladd et al. 1981). Even though the sex attractant captures only male beetles
when used alone, when  exposed in the presence of the floral lures it causes increased captures of
both male and female beetles (Ladd et al. 1981, Klein et al. 1981).

     Although large numbers of  beetles can be captured by Japanese beetle traps, the best uses
for the traps is still being studied. Klein (1981b) reported on several studies where traps were used
to reduce infestations of beetles. However, most workers agree that traps cannot be depended
upon to protect specific  plants from beetle  feeding (Fleming 1976, Ladd and Klein 1982, Fleming
1969). Recent studies involving  heavy populations of beetles in  Kentucky showed that there was
an increased  damage to plants in the vicinity of Japanese beetle traps (Gordon and Potter 1985,
1986). The use of traps did not increase  the population of larvae in  near by turf. It has been
suggested  that an antifeedant material such as neem may be applied to foliage to protect it when
traps are used in an area. A commercial product, Margosan-O (W. R. Grace, Co., Fogelsville, PA),
has recently been made available for testing. It is still to early  to establish the value of such  a
product. Since the material is an antifeedant for the Japanese beetle, and not a repellent, it would
appear that there is little future in spraying it on turf to discourage adult egg laying as had been
suggested  (Bio Integral Resource Center 1987).
Other  Attractants

     Sex attractants have been demonstrated for the northern and southern masked chafers,
Cyclocephala borealis Arrow, and & immaculata (Oliver) (Potter 1989). More recently, both a sex
attractant and an aggregation pheromone have been found in the green June beetle, Cotinus nitida
(L) in Arkansas (Domek and Johnson 1987,1988). In addition, a chemical attractant, butyl sorbate
was shown to be an attractant  for males and females  of the  European chafer(Tashiro 1987).
Commercial development of these will await the identification of the pheromones involved and a
demonstration of the value of the attractants.


     Bacillus  popilliae is the most important commercially available microorganism available for
suppression of white grub species. Its value should increase in the next few years if the promise of
production  on artificial media is realized.  We need  more information about the value of other
microorganisms such as the fungi and  protozoa so that they can be integrated into suppression
programs. Attractants for the Japanese beetle will continue to be available to consumers who wish
to use  them. More information is needed on the value of all attractants  for scarab beetles so their
full potential can be reached.

S. Ahmad, H. T. Streu, and L M. Vasvary. 1983. The Japanese beetle: A major pest of turfgrass. AJTIIL Lawn Ap_pl 4(2):
T. G. Andreadis, and J. L. Hanula. 1987. Ultrastructural study and description of Ovavesicula popilliae N.G., N. Sp.
        (Microsporida: Pleistophoridae) from the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). i
        Protozool. 34:15-21.
Bio Integral Resource Center. 1987. Least Toxic Lawn Management. Bio Integral Resource Center, Berkeley, CA, 38 pp.
D. G. Boucias, R. H. Cherry, and  D. L Anderson. 1986. Incidence of Bacillus  popilliae in  Ligyrus subtropicus and
        Cyclocephala parallels (Coleoptera: Scarabaeidae) in Florida sugarcane fields. Environ. Entomol. 15:703-706.
H. D. Surges. 1981. Microbial Control of Pests and Plant Diseases 1979-1980. Academic Press, London, 949 pp.
D. Chittick. 1987. Fairfax Biological Laboratory, Clinton Corners, NY. Personal communication.
P. P. Cobb. 1988. Warm season turf insect pests. Am. Lawn Appl. 9(7): 24-25.
S. Daar. 1988. Japanese beetles, an integrated approach to protecting your lawn. Fine Gardening 1(1):52-55.
J. M. Domek, and D. T. Johnson. 1988. Demonstration of semiochemically induced aggregation  in the green June beetle,
        Cotinis nitida (L.) (Coleoptera: Scarabaeidae). Environ. Entomol. 17:147-149.
J. M. Domek, and D. T. Johnson. 1987. Evidence of a sex pheromone in the green June beetle, Cotinus nitida (Coleoptera:
        Scarabaeidae). J. Entomol. Sci. 22:264-267.
W. E. Fleming. 1968. Biological Control of the  Japanese Beetle. Technical Bulletin  No. 1383. U.S. Department  of
        Agriculture. U. S. Government Printing Office, Washington, DC, 78 pp.
W. E. Fleming. 1969. Attractants for the Japanese Beetle.  Technical Bulletin  No. 1399. U.S. Department of Agriculture.
        U. S. Government Printing Office, Washington, DC, 64 pp.
W. E. Fleming. 1972. Biology of the Japanese  Beetle. Technical Bulletin No. 1449. U.S. Department of Agriculture. U.  S.
        Government Printing Office, Washington, DC, 129 pp.
W. E. Fleming. 1976. Integrating Control of the Japanese Beetle-A Historical Review. Technical Bulletin No. 1545. U.S.
        Department of Agriculture. U. S. Government Printing Office, Washington,  DC, 64 pp.
W. E. Fleming, and T. L. Ladd. 1979. Milky  Disease for Control of Japanese beetle Grubs.  Leaflet No. 500. U.S.
        Department of Agriculture. U. S. Government Printing Office, Washington,  DC, 6 pp.
J. R. Fuxa. 1987. Ecological considerations for the use of entomopathogens in IPM. Ann. Rev. Entomol. 32:225-251.
J. R. Fuxa, and Y. Tanada. 1987. Epizootiology of Insect Diseases. Wiley, NY, 555 pp.
F. C. Gordon, and D. A. Potter. 1985.  Efficiency of Japanese  beetle  (Coleoptera: Scarabaeidae) traps in  reducing
        defoliation of plants in the urban landscape and effect on larval density in turf. J. Econ. Entomol. 78: 774-778.
F. C. Gordon, and D. A. Potter. 1986. Japanese beetle (Coleoptera: Scarabaeidae) traps: evaluation of single and multiple
        arrangements for reducing defoliation in urban landscape. J, Econ. Entomol. 79:1381-1384.
L A. Hall. 1987. Fort Valley State College,  Fort Valley GA, Personal communication.
J. L Hanula,  and T. G. Andreadis. 1988. Parasitic microorganisms of the Japanese  beetle (Coleoptera: Scarabaeidae)
        and associated Scarabaeidae larvae in Connecticut soils. Environ. Entomol. 17:709-714.
J. L. Hellman. 1988. University of Maryland, College Park, MD, Personal communication.
T. Jackson. 1988. MAFTech, Lincoln, New Zealand. Personal communication.

T. A. Jackson, J. F. Pearson, and G. Stucki. 1986. Control of the grass grub, Costelytra zealandica (White) (Coleoptera:
        Scarabaeidae) by application of the bacteria Serratia spp. causing honey disease. Bull. Entomol. Res. 76:69-76.
S. Keller. 1986.  Control of May beetle grubs (Melolontha  melolontha  L) with the  fungus Beauveria brongniartti
        (Sacc.)Petch. Pp. 525-528 in: R. A. Samson, J. M. Vlak, and D. Peters, eds.. Fundamental and Applied Aspects
        of  Invertebrate  Pathology. 4th International Colloquium  of  Invertebrate  Pathology,  Wageningen,  The
        Netherlands, 711 pp.
M. G. Klein.  1978. Unpublished data
M. G. Klein.  1981a. Advances in the use of BacjJJus pjjpilia® for pest control. Pp. 183-192 in: H. D. Rurges, ed., Microbial
        Control Of Pests aM Plant Diseases 1970-1980. Academic Press,  London, 949 pp.
M. G. Klein.  1981b. Mass trapping for suppression of Japanese beetles. Pp. 183-190. in:  E. R. Mitchell ed., Management
        of Insect Pests with Semiochemicals. Plenum, NY 514 pp.
M. G. Klein.  1982. Biological suppression of turf insects. Pp. 91-97 in: H. D. Niemczyk, and B. G. Joyner eds., Advances
        in Turfgrass Entomology. ChemLawn Corp., Columbus, OH. 149 pp.
M. G. Klein.  1986. Bacillus popilliae: prospects and problems. Pp. 534-537 in: R. A. Samson, J. M. Vlak, and D. Peters,
        eds., Fundamental and Applied Aspects of Invertebrate Pathology. 4th International Colloquium of Invertebrate
        Pathology, Wageningen, The Netherlands, 711 pp.
M. G. Klein.  1988a. Pest management of soil-inhabiting insects with microorganisms. Agric. Ecosys. & Environ. In Press.
M. G. Klein.  1988b. Unpublished data.
M. G. Klein, J.  H. Tumlinson, T. L Ladd, Jr., and R. E. Doolittle.  1981. Japanese beetle (Coleoptera:  Scarabaeidae):
        response to synthetic sex attractant plus phenethyl propionate: eugenol. J. Chem. Ecol. 7:1-7.
T. L. Ladd, and  M. G. Klein. 1982. Controlling the Japanese Beetle. Home  & Garden Bulletin No. 159. U.S. Department
        of Agriculture. U. S. Government Printing Office, Washington, DC,  14 pp.
T. L. Ladd, M. G. Klein, and J. H. Tumlinson. 1981. Phenethyl propionate + eugenol + geraniol (3:7:3) and Japonilure: a
        highly effective joint lure for Japanese beetles. J. Econ. Entomol. 74:665-667.
H. D. Niemczyk. 1980. The influence of application timing and posttreatment irrigation of the fate and effectiveness of
        isofenphos for control of Japanese beetle (Coleoptera;  Scarabaeidae) larvae  in turfgrass. JL  Econ. Entomol.
H. D. Niemczyk, and R. A. Chapman. 1987. Evidence of enhanced degradation of isofenphos in turfgrass thatch and soil.
        J. Econ. Entomol. 80: 880-882.
J. November. 1988. Runoff and ground water contamination. Amer. Lawn Appl. 9(7): 40-42.
F. Obenchain. 1989. Ringer, Eden Prarie, MN. Personal communication.
D. A. Potter. 1989. Flight activity and sex attraction of northern  and southern masked chafers in Kentucky turfgrass. Ann.
        Entomol. Soc. Amer. 73:414-417.
R. A. Samson, J. M. Vlak,  and  D. Peters.  1986. Fundamental and Applied Aspects  of  Invertebrate Pathology. 4th
        International Colloquium of Invertebrate Pathology, Wageningen, The Netherlands, 711  pp.
H. Tashiro. 1987. Turfgrass Insects of the United States and Canada. Cornell Univ. Press, Ithaca, NY, 391 pp.
J. H. Tumlinson, M. G. Klein, R. E. Doolittle, T. L. Ladd, and A. T. Proveaux. 1977. Identification of the female Japanese
        beetle sex pheromone: inhibition of male response by an enantiomer. Science. 789-792.
M. G. Villani, R. J. Wright, and P.  B. Baker. 1988.  Differential susceptibility of Japanese  beetle, Oriental beetle, and
        European chafer (Coleoptera: Scarabaeidae) larvae to five soil insecticides. J. Econ. Entomol. 81:785-788.
P. J. Vittum. 1988. Controlling Northern turf insects. AmSL Lawo AppJ. 9(7): 20-22.
P. J. Vittum. 1987. Home lawn IPM update. Amer. Lawn Appl. 8(10): 27-29.

G. W. Warren, and D. A Potter. 1983. Pathogenicity of Bacillus popilliae (Cyclocephala strain) and other milky disease
        bacteria in grubs of the southern masked chafer (Coleoptera: Scarabaeidae. J. Econ. Entomol. 76:69-73.
T. L. Watschke, G. Hamilton, and S. Harrison. 1988. Is pesticide runoff from turf increasing? AmsL Lawn AppJ. 9(7): 43-44.
G. W. West, H. D. Surges, R. J. White, and C. H. Wyborn. 1984. Persistence of Bacillus thuringiensis parasporal crystal
        insecticidal activity in soil. J. Invert. Pathol. 44:128-133.

Mention of a proprietary product does not constitute endorsement by the USDA. In cooperation with
the Ohio  Agricultural Research and  Development Center, Ohio State University, Wooster and
approved for publication as Journal Article No. 268-88.


                              Dr. Milton E. Kageyama
                                Dr. Larry R. Widell

                             O. M. Scott and Sons Co.
                                Research Division
                               Marysville, OH 43041

    Another chapter has begun  in the never-ending struggle between man and that baneful,
pernicious weed we collectively call annual bluegrass (Poa annua). Within the past several years,
an increasing number of golf course superintendent have chosen turf growth retardants (TGRs)
as an option to their existing, rather unsuccessful, control methods for reducing the spread of this
undesirable grass. This new dimension to Poa annua control is especially appealing to those who
desire a gradual transition to the more desirable grasses, such as bentgrass, without temporarily
taking greens and fairways out of play. However, we have observed that some turfgrass managers
are more adept than  others  at  making turf growth  retardants work for them.  It cannot be
overemphasized that product knowledge and careful execution of the TGR program for Poa control
are the keys to greater success in the use of these products.


    Turf growth retardants are a diverse group of plant growth  regulators that act by blocking
gibberellic acid  (GA) biosynthesis, a  plant hormone  influencing cell elongation,  among other
functions. Retardant activity on turfgrasses results in shortened stem internodes and reduced leaf
and rhizome elongation. Diversion of photosynthate and altered hormone levels may be responsible
for increased tillering and subsequent greater turf density observed with TGR applications. These
effects are overcome by application of GA.
    Examples of turf growth retardants currently being used on golf courses either commercially
or on an experimental basis include paclobutrazol (Fertilizer + TGR Poa annua control from O. M.
Scott & Sons Company) or flurprimidol  (Gutless from Elanco  Products). Both are gibberellin
antagonists but  are not similar in chemical structure. Paclobutrazol is a triazole, a compound
containing a five-membered ring structure with three nitrogen atoms. Flurprimidol belongs to a class
of compounds possessing a six-membered ring containing two nitrogen  atoms, the pyrimidines.
Despite their chemical dissimilarities,  both compounds work in  the same manner, selectively
controlling the growth of Poa annua and thereby resulting in a shift in competitive ability to favor the
more desirable, perennial grasses.


                             HOW DO TGR's WORK?

     The most important concept for the golf course superintendent to keep in mind when using
growth retardants for Poa annua control is that these compounds are mobile only in the xylem
(movement upward only) and  therefore require  root uptake to reach basal growing points. In
addition, differential species sensitivity is primarily attributed to greater uptake of the retardants by
the shallower-rooted annual bluegrass plants.  Turfgrass managers can enhance TGR response
on Poa and maximize tolerance on desirable grasses by remembering this mode of action and
employing management techniques prior to application that are effective  in spatially separating
actively-absorbing root zones of Poa annua from other grass roots.
     Within one to two weeks following application of TGRs, growth  control and discoloration of
annual bluegrass will become evident. During the period of growth regulation, the Poa annua plants
will remain alive but be very stunted in growth. Bentgrass will continue to grow but in a more prostrate
condition and may possibly appear "stringy" during this period of Poa growth regulation.  Poa
seedhead suppression  is attained by a reduction in the stalk, greatly reducing seedhead visibility.
The tremendous proliferation of spring seedheads causing poor playing surface conditions can be
avoided by making TGR applications in the spring just prior to the time seedheads begin emerging
on south-facing slopes or in warm soil areas. Applications at this time will greatly improve playing
conditions on fairways and greens for up to six weeks. Some seedheads will become visible in late
May/early June, but these will also be somewhat stunted and should not seriously impair payability.
Fall applications can also effectively reduce  Poa seedhead visibility the following spring but for a
shorter duration (three to five weeks). Poa regreening should occur just prior to regrowth about five
to ten weeks after application . Inspection of the fairways and greens at this time should reveal
greatly improved coverage of bentgrass at the expense of annual bluegrass.

     • Severe reduction in growth of Poa annua 7 to 14 days after application, lasting from 4
       to 10 weeks
     • Shoot tissue discoloration (yellow-green to brown) of Poa annua for 3 to 8 weeks
     • Aggressive growth of bentgrass for 4 to 8 weeks after an initial 14 to 20 day period of
       reduced (50%) growth
     • Spring seedhead stalk stunting for 5 to 6 weeks with spring or previous fall applications
     • Regreening/regrowth of Poa annua 5 to  10 weeks after application
     • Enhanced greening of bentgrass for 6 to 8 weeks
     • Reduction in Poa annua coverage after application by 10 to 50%
     • No reduction in bentgrass root growth
     • No thinning of Poa annua under non-stress conditions

                          PERFORMANCE VARIABILITY

     It is not unusual for pesticides to perform variably. This is especially true for growth regulators
where the desired rate may be a fine line between tob much and too little activity. Delivery of effective
doses of TGRs into the Poa annua plant can be achieved by considering the physico-chemical
characteristics of TGRs. For instance,  paclobutrazol displays rather low water solubility (30 ppm)
and readily adsorbs to organic matter and thatch. Therefore, its movement through the soil profile
is very limited except in sandy soils containing little organic matter. The insightful turf manager can
usually predict the nature of the growth regulation response of TGRs on Poa annua vs. bentgrass
by reflecting on the seasonal root growth dynamics of the two turf types and the soil type (texture).
The greatest differential response can  be achieved with early summer applications on heavy soils
when uptake of nutrients and water occurs lower in the soil profile than paclobutrazol can move.
However, this response may not  be desirable since it may result in aesthetically unpleasing color
on Poa annua for too long a time,  especially on greens.  The target regulation differential that is
most accepted by turfgrass managers  occurs with mid-spring and late summer applications when
a moderate amount of activity is achieved on Poa annua. Less differential growth regulation will be
seen with fall applications when  Poa annua roots begin to move deeper into the soil profile and
cooler, more moist weather conditions favor the growth of Poa.
     Watering-in is essential for these  systemic TGRs to work, whether they are formulated as a
granule or liquid. It is even more important to remove liquid TGRs from foliar surfaces to minimize
foliar uptake, volatilization, and photodecomposition.  Recommendations state the need for 1/4" of
water within 48 hours to optimize  activity, except in heavily-thatched areas where greater amounts
are needed. Aerating prior to application has proven to be very beneficial in these areas. Lack of
adequate rainfall or irrigation after application can greatly delay and/or reduce activity, especially
on heavy soils.
     The degree of growth  regulation can also be influenced by turf  biotype.  Conversion  to
predominantly bentgrass  greens where  the  initial  amount of Poa  annua is high  has been
unsuccessful with the more upright colonial bentgrasses.  Apparently  these bentgrasses are not
aggressive enough to dominate while Poa annua is under regulation. Conversion on fairways also
appears to be less successful where the more perennial Poa annua biotypes proliferate.

                             PROGRAM SCHEDULING

     It must be  understood  that Poa  annua control with TGRs is a gradual process, requiring
sequential applications until the desired level of control is achieved. Applications must be made in
a constant, routine manner twice  a year. Omitting applications before this time can lead to slower
long-term control. Once control has been achieved, routine annual treatments in late summer or
early fall should keep the Poa in  check. Repeat applications over a two to three year period may
be required in some areas of high initial contamination. Programs using lower application rates with
greater application frequency do not provide any greater long-term benefits on fairways. However,
recent research on greens has shown  promise when using lower rates every three to four weeks
in eradicating Poa annua without as much discoloration.
     Proper time of application has already been considered with respect to root growth dynamics.
Timing must also be considered with respect to seeding, aerating and topdressing, and herbicide
application. The superintendent's  primary consideration in the fall should be the sequence of events

with respect to overseeding, a highly-recommended practice for high contamination areas. TGRs
offer greater flexibility than  most preemergence controls since applications are not phytotoxic to
bentgrass seedlings. However, to avoid seedling growth regulation and slowed fill-in, wait at least
six weeks after overseeding before application; or in treated areas, wait at least two weeks after
application before overseeding.

                                   AREAS OF USE

     Retardants are effective in eradicating Poa annua on fairways, greens, and collars. Long-term
control of Poa on tees is more difficult because of the excessive wear on perennial turfgrasses and
the advantage annual bluegrass has reestablishing in divoted areas routinely irrigated. Overseeding
and filling divots with a sand/seed mix has proven to be a sound management practice in conjunction
with TGR use on  especially those tees containing large amounts of Poa annua. The unevenness
of turf height on collars and greens caused by TGR use can result in undesirable lies and bumpy
putting conditions for a period of time. A light sand topdressing during  the cooler  periods of  the
season can certainly improve ball roll on  greens. Applications of retardants to nearby perennial
bluegrass collars  should be avoided since the extent to discoloration in these highly visible areas
may not be acceptable.

                            THE NEED FOR NITROGEN

     Best encroachment and stoloniferous  action  of bentgrass on fairways and greens  are
accomplished when these areas are well-fertilized at the time of TGR application. Abiding by  the
long-standing rule of encouraging the bentgrass by starving the predominantly annual bluegrass
turf through a very judicious fertilizer program does not necessarily apply when using TGRs.
     Conversely,  moderate-to-heavy fertilizations just before bentgrass starts growth in the spring
will actually provide  greater Poa annua suppression. Spring applications of TGR and nitrogen
should be applied early enough to  minimize  the risk of lush growth when hot severe weather
develops  and Pythium  invasion is likely. In areas  of recurrent disease problems, fungicide
applications should be used on a preventative  basis and intervals tightened somewhat, since TGRs
can increase the turf's susceptibility to Pythium and snow mold. In addition to shifting the uptake
and assimilation of nitrogen to bentgrass, the use of TGRs with fertilizers also results in a very
dramatic greening of bentgrass, lasting longer than  conventional  fertilizers alone. Poa annua  will
also benefit from  this combination treatment after the growth retardation subsides, resulting in a
greener, healthier Poa annua/bentgrass turf throughout the  ensuing stress periods.

                                 OTHER BENEFITS

     Not only will TGRs provide more consistent, higher quality bentgrass fairways and greens  but
other benefits that the superintendent can enjoy include (1) significant labor savings in the spring
and fall due to fewer required mowings on fairways and less clippings to dispose of on greens, (2)
reduced water use due to the lower water requirements of bentgrass (a significant benefit in areas
faced with impending watering restrictions), (3) reduced fertilizer use,  and (4) faster, more true ball
roll on greens containing primarily bentgrass.

    The science of growing turfgrass has taken a significant leap forward with the introduction of
growth retardant chemistry. Users of these sophisticated tools must be informed about their proper
application and the way they fit into existing turf management programs. It is essential to inform the
greens committee and membership of this course of action to explain the visual results. It is also a
good  idea in some situations to begin a program on a  limited basis to understand how these
chemicals are used and what to expect. The progress of this program can most easily be measured
by leaving a small portion of one fairway untreated by covering the area with a cloth or piece of
    The committed, informed superintendents are now making major strides in controlling the fate
of their golf courses. Growing and maintaining high quality bentgrass fairways and greens is not
an accident but the result of responsible blending of turfgrass art and science.


Evaluation of the Site/Pest Complex:
 A Starting Point for Development
   of an Urban Pest Management
      System for Turfgrass


                                  Anne R. Leslie
                       U.S. Environmental Protection Agency
                                 401 M Street SW
                              Washington, DC  20460
    A number of promising biological controls and cultural practices for turfgrass have been
presented in detail above. Although some of these are not yet available for general use, they are
expected to form an important part of the management tools needed to deal with pest problems.
However, the basic steps to design an IPM program for turfgrass can be presented so that turfgrass
managers can make best use of all control methods and realize economy in management with no
loss of turfgrass quality.

    We start with our working definition: Integrated Pest  Management is the coordinated use of
pest and environmental  information with available pest control methods to prevent unacceptable
levels of pest damage by the most economical means, and with the least possible hazard to people,
property and the environment. The goal of the  IPM approach  is to manage pests and the
environment so as to balance costs, benefits, public health and environmental quality. IPM systems
use all available technical information on the pest and its interaction with the environment. Because
IPM programs apply a holistic approach to pest management decision-making, they take advantage
of all appropriate pest management options, including but not limited to pesticides. Thus, IPM is:
    • A system utilizing multiple methods
    • A decision-making process
    • A risk reduction system
    • Information intensive
    • Cost effective
    • Site specific.


    A generic pest management system includes the eight distinct steps that are outlined here:
1.  Define the roles of all the people involved in the pest management system (i.e., occupant, pest
   manager,  decision-maker), assure understanding  and  establish communications between
2.  Determine the management objectives for each of the specific areas of the site as a basis for
   deciding on possible control methods for the pest.
3.  Set action thresholds-a point when pest populations or environmental conditions indicate that
   some action must be taken; no action is taken until that point is reached.


4.  Monitor the site environment and pest population on a periodic, consistent basis to determine
    when the action threshold is reached and to determine whether the action taken is effective.
5.  Take action that modifies the pest habitat to reduce carrying capacity of the site, exclude the
    pest, or otherwise make the site environment incompatible with the needs of the pest.
6.  Take appropriate pesticidal action. A preferred pesticide would provide the  longest dwell time
    in contact with the pest while presenting the  least possible hazard to the people, property and
    the environment. It should be applied when the pest is in its most vulnerable stage.
7.  Evaluate the results of the habitat modification and pesticidal treatment actions by periodically
    monitoring the site environment and pest populations.
8.  Keep written records of site pest management  objectives, monitoring methods and data
    collected, actions taken, and the results obtained by the pest management system methods.

     All components of  this  system must be addressed  and  implemented in some form for the
system to be most effective. Omission of portions of the system, in our experience, has led to greater
unnecessary dependence on repeated pesticidal treatments.
     Since IPM is site specific and information intensive, each site manager will  need to develop a
plan that meets the management goals established in Step One. Some thought should be given to
identify all the people who fall into the categories of occupant, pest manager and decision-maker.
     For instance,  people who do not golf but who use the land neighboring a golf course must be
considered  occupants  if management  practices on  the  course can  potentially  impact their
environment. Similarly, the golf course management, in setting management goals that include very
short, smooth greens for fast play,  should consider the needs of the people using a water supply
that may be impacted  by the pesticides required to attain the desired greens quality. That
consideration might involve  choosing between  a costly groundwater monitoring  program  and  a
slightly altered mowing height that can result in a lower pest pressure. Other innovative solutions
to problems may be achieved if all  the "actors"are willing  to communicate their real  concerns and
work productively toward their resolution.
     An outstanding example of the  progress that can be achieved is the cooperative  effort in
Massachusetts between the Massachusetts Golf Course Superintendents Association and the state
regulatory agencies and universities. This effort has led to implementation of IPM programs at golf
courses across the state.

     With the above components in mind, we can define the strategies that would  be important for
turf areas with different management goals. A number of strategies will be listed for three kinds of
sites. A good monitoring plan, with action thresholds and proper record keeping, will be used to
evaluate the effectiveness of these strategies.

Site A:  High Management Turf.

Example:  Golf Course Greens and Tees

1.  Establish pest-resistant varieties of grass suitable to the site, climate, and expected use.
2.  Use bacterial or biochemical control, such as plant growth regulators, for poa annua on tees
    and greens.

3.  Use biological controls, such as nematodes for control of white grubs, and endophytic grasses
    for surface feeding insects.

4.  Raise  mowing  height  and  reduce watering frequency to  reduce  weed  populations and
    expression of fungus disease; evaluate problem areas and the need for drainage control and/or
    irrigation system improvements; use slow release fertilizers along with soil amendments.
5.  Use caning and syringing as methods of stress reduction to reduce threat of fungus damage
    in summer months.

6.  Put fungicide use on a strict degree/moisture threshold schedule by  use  of computerized
    monitoring and  diagnostic tests to determine disease potential; select least invasive effective
    fungicidal  treatment; consider rotation or tank mixes of fungicides to reduce resistance buildup.
7.  Monitor for changes in populations of flora and fauna, beneficial as well as destructive.
8.  Educate the public and the course management on the strategies being used at the site.

Site B:   Medium Management Turf.
Example:   Home lawn or public lawn other than golf course
1.  Evaluate the soil for pH, texture and type; use soil amendments and consider renovation rather
    than heavy use of pesticides to solve problems.
2.  Overseed or plant a variety that suits the use pattern  and site.
3.  Set up action thresholds and monitoring methods for weeds and insects. Note that disease
    problems  in home lawns are  almost always due to over fertilization and over watering. Note
    also that there should be greater tolerance for pest populations and the use stress on the grass
    will probably be less than on site A.
4.  Establish  proper cultural practices; for example, water deeply when the wilt  point is reached
    rather than on a calendar schedule, use slow release fertilizer, increase mowing height and
    frequency, leave  clippings on the lawn and  include  periodic aeration by vertical mowing or

Site C:   Low Maintenance (or "NoPesticide")Turf.
Example:   Some Park Sites, Homeowners Interested  In Alternatives to Tlirf
1.  Use mowing to control woody plants, and encourage growth of native species, rather than
    adhere to  a monoculture of grass.
2.  Use grass varieties suitable to the use pattern; have paving where heavy traffic is expected.
3.  Convert  some  areas  to meadow  by  planting  wildflower cover,  minimizing  long  term
    maintenance, especially in areas where it is difficult to maintain grass.
4.  Use monitoring to help with decisions on aggressive plant control. Not much is known of the life
    cycle of many such plants, and if this is studied carefully, the manager will be better able to
    choose the least invasive method of control.
5.  Use biological controls on pests wherever feasible.
6.  Use good  cultural practices as in Site  B.


    To continue to improve IPM programs, there should be continuing research on a number of
    questions, such as:
1.   What are the effects of pesticides on beneficials in greens and tees?
2.   Is there a pest population difference between  greens, tees,  fairways and roughs that is the
    result of pesticide use, and are pesticides perpetuating problems?
3.   What natural predator biocontrols can be found to decrease high populations  of pests on
    monoculture areas?
4.   Does healthy turfgrass act as a  barrier  to surface  water  and  groundwater pesticide
    contamination in golf  course  watersheds?   What  kinds  of  irrigation systems and  soil
    amendments will minimize problems?
5.  What are the real economic benefits of an IPM program for turfgrass?
    EPA is planning  projects at several of the sites discussed. A Memorandum of Agreement is
    being processed between EPA and the Military  District of Washington to establish  cooperation
    on  a survey  of  IPM practices at military establishments  in the D.C. area. This agreement
    addresses the presidential order of September 2,1979, which requests all agencies to "support
    and adopt IPM strategies whenever practicable" and to  "assess the  potential for increased
    emphasis on  integrated  pest  management."  The  military  establishments  offer managed
    turfgrass at all levels listed, including parade grounds, home lawns, parks and golf courses.
         In addition, because golf courses involve  high level management and are highly visible
    targets for environmental concern, EPA has proposed to develop an IPM demonstration project
    at several golf courses in the northeast. We believe that such projects will greatly contribute to
    the establishment  of safe, sound pest management of the growing recreational land  use
    demanded by the American public. Such land use should be compatible with the surrounding
    environment  and the  plans  should address  the reasonable concerns of the  neighboring
    residents. By cooperative efforts landowners should be able to develop their holdings as they
    wish and still contribute something of value to the entire community.
         Only continued, careful investigation and a  commitment to  meaningful  use  of  IPM
    techniques in urban turfgrass management will  enable  managers to achieve reduction of
    dependence on chemical controls. It is hoped that expert systems will be developed that will
    assist the professional turfgrass manager. The final chapter addresses  this technology  and
    what such a system can and cannot do.

                                   Jan P. Nyrop
                            Department of Entomology
                    New York State Agricultural Experiment Station
                                 Cornell University
                                 Geneva, NY 14456
                                   Bernie Huber
                                   IPM Program
                    New York State Agricultural Experiment Station
                                 Cornell University
                                 Geneva, NY 14456
                                   Walter Wolf
                          Department of Computer Science
                          Rochester Institute of Technology
                                  Rochester, NY
    Naive, prophylactic application of pesticides continues to be a frequently used pest control
tactic. This approach to pest control results in needless expense by crop managers, unjustified
exposure of the environment to chemical toxicants, and hastened resistance by pests to chemical
pesticides. To counter the myriad costs of excessive chemical pesticide use, a more economic and
ecologically rational  pest control paradigm has been advocated;  integrated pest  management
(IPM). Ideally, IPM entails a multi-faceted pest control effort through the use of cultural practices,
the conservation and possible augmentation of biological control agents, and the judicious use of
chemical pesticides.  Even in its most simplified form of using monitoring and action thresholds to
schedule pesticide applications, IPM can greatly reduce the use of chemical pesticides.  In many
cropping systems a library of IPM  technologies has been developed through research. However the
adoption and use of IPM has been frustratingly slow.
    Wearing (1988) groups causes for this slow acceptance into five classes. First, requisite tools
for IPM such as simple monitoring methods and selective control strategies may be lacking. Second,
the actual and/or perceived costs of practicing IPM may not be conducive to its adoption. Third,
deficiency in knowledge required by growers to use IPM methods may hinder adoption. Fourth,
crop managers  are generally satisfied with chemical control and  often lack confidence in IPM
methods. Finally, the lack of trained experts needed to educate and provide consultation to growers
about  IPM may limit  its adoption. This paper will focus on a relatively new computer technology
that offers a means of overcoming this last impediment to the adoption of IPM.
    Use of IPM necessitates a considerable degree of expertise in applying and integrating many
sources and types of information and often requires the simultaneous consideration of multiple crop
protection goals. In addition crop managers often do not have the skill or background to effectively
use many IPM tools. A recently  proposed  solution  to the  problem of insufficient  availability of


expertise in IPM is the development of expert or knowledge based systems (Coulson and Saunders
1987, Naegle et al 1986, Stone et al 1986). Unfortunately, the term "expertsystem" has been badly
misused  and misunderstood.  Thus we will  employ the more  generic  name"knowledge-based
systems" (KBS). In this paper we present our views on the requirements, pitfalls and opportunities
associated with developing KBS's for use in pest management. These views have developed as a
result of  our work on a KBS for use  in apple pest management (EASY-MACS;  Expert Advisory
SYstem for Managing Apple Cropping Systems) and through study of the literature dealing with
KBS's. While EASY-MACS deals specifically with apple cropping systems, the discussion presented
here is germane to all pest management systems including those in the urban environment. The
paper is composed of three sections.  First, we provide a brief overview of what knowledge based
systems are and present some details about the EASY-MACS system in order to illustrate an actual
system. Our intent here is to provide a setting for the remainder of the paper and  not to provide a
full explanation of how knowledge based systems work. There are a number of accessible reviews
detailing the nature of KBS's (e.g. Waterman 1986, Davis 1986). In the second section, we discuss
requirements for building a KBS for use in pest management and present pitfalls that we and others
have encountered  in  developing knowledge based systems.  An  understanding of these
requirements and pitfalls is important because they are frequently masked by the hyperbole that
ensconces a new technology. Finally we discuss the opportunities for use of KBS's in IPM.


     A knowledge based system is a computer program specially designed to represent human
expertise in a particular domain  of knowledge. It attempts to mimic a human being's ability to make
complicated decisions and is designed to assist a user to make similar decisions.  For this reason,
knowledge based systems may also be called decision support systems. These  systems act as
intelligent assistants to human experts, and also assist people who might not otherwise have access
to expertise. They have been developed and used extensively in medicine and industry, and are
now finding application in agriculture.
     The techniques used to develop KBS's are products of investigations that have delved into the
possibility that computers could behave in a way that would be perceived as intelligent. This line of
research, known as artificial intelligence (Al) had its roots in a conference that took place in 1956
at Dartmouth College. Early work in Al emphasized development of computer systems that could
solve very general problems. Repeated failures at this endeavor led to the realization that much of
the power in problem solving lies in possessing a great deal of specific knowledge about the problem
and its likely solution. This led to research that examined how to represent such knowledge on a
computer and how to manipulate  it. The  end products of this work are the tools for developing
knowledge based systems.

     The principal parts of an expert system are a knowledge  base coupled with an inference
engine, and a  user  interface.  The knowledge base is a  collection of facts, expert opinions,
'rules-of-thumb' or heuristic knowledge, and procedural knowledge including relationships amongst
these facts, etc. The knowledge is that which an expert would employ to solve a particular problem.
The inference engine drives  the system during a consultation by a user. It controls what portion of
the knowledge base should be used to solve a particular problem.

     One of the most frequently used methods of representing knowledge is through  a construct
known as if - then rules. If the antecedent of such a rule (the if part) is true, then  the consequent
portion (the then part) is also true. An example of an if - then rule in pest management might be; if


the density of pest A is greater than Y and if the median development of pest A is at least Z then it
is appropriate to treat for pest A. The inference engine controls the linking of the if - then rules in
order to reach a conclusion. Other rules would likely have to be used to determine the density of
pest A and if the median development exceeded Z. The inference engine would control the execution
of these rules. One  can also envision a group of rules being used to determine the best pesticide
to use once it is established that a treatment should be made.

     The user  interface  elicits needed  information  from the user, presents  the results of a
consultation (i.e. a diagnosis or recommendation) to the user,  and offers explanations supporting
those results.  In addition to these major components, a KBS may also access databases and
simulation models to obtain needed information.

     One way to picture a KBS is by way of analogy to a system of logic (Denning 1986). A system
of logic consists of axioms that  are self-evident or universally recognized truths and rules of
inference. New knowledge, usually in the form of proofs, are derived from this system by sequencing
strings of axioms or  prior proofs using the rules of inference. A KBS is analogous with some notable
differences. A KBS  may contain axioms but it also  contains other statements  of fact (e.g., expert
opinion) that are used as axioms but clearly do not meet the definition of an axiom. In addition, the
rules of inference used by a KBS will often not be universally agreed upon.
     We will now provide a description of the  EASY-MACS system in order to more specifically
illustrate some of the points made above. EASY-MACS is designed to be  a coach for implementing
integrated management of arthropod pests of apples.  It runs on an Apple Macintosh computer and
is being developed  using NEXPERT (Neuron  Data, Palo Alto,  CA). Like a human consultant, the
system asks the client for detailed information about  the current condition  of his orchard block. It
 then makes a recommendation for action based upon that information, the history of that orchard
 block,  and the system's own knowledge of pest dynamics. EASY-MACS may also warn the user
 of upcoming events and make tentative predictions about the future.
     In the process  of arriving at a recommendation, EASY-MACS takes into accountstate-of-the-
 world considerations, such as the physical makeup and the phenological stage of the apple trees,
 and the current pest infestation level. These external conditions are then  combined with internal
 considerations, such as the interactions that occur when more than one pest is present, or that the
 presence  of a biological control  agent is important, or  user preference requests an alternate
     The system is made up of three components: 1)  A Rule Base and Inference Engine. The rule
 base encodes knowledge needed to make decisions about apple pest control. The inference engine
 links relevant portions  of the knowledge base  in  order to obtain needed data from  a user and to
 arrive at a recommended course of action. The following is a fairly complex example of the kind of
 considerations that  compose a rule and allow the system to arrive at a recommendation. The first
 block of statements  (the MIF"part) are conditions which may or may not be true. If all  the conditions
  listed in a rule are true, then the hypothesis (the 'THEN"part) is true and  the actions (the last block
  of statements)  associated with that rule are carried out. These actions  may  in turn affect the
  evaluation of further conditions composing other hypotheses.

    IF the phenological stage of the block is Pink,
    AND Spotted Tentiform Leaf miner infestation is a problem,
    AND Rosy Apple Aphid infestation is not a problem,
    AND the block has a history of Oblique Banded Leaf roller damage,
    AND Recommend applying Lannate at Petal Fall to control Spotted Tentiform Leaf miner
         and Oblique Banded Leaf roller (TRUE),
    AND you choose not to follow this recommendation,
    AND the pesticide Dimilin is not currently available,
    AND  Recommend applying Vydate at Pink  to  control  Spotted Tentiform  Leafminer
    THEN a recommendation for pest control has been made,
    AND record that Vydate has been recommended at Pink to control Spotted Tentiform
    AND record that Rosy Apple Aphid was not a problem at Pink,     ^  ,
    AND inform the user that he should sample for Oblique Banded Leafroller at Bloom.

    In this example the conditions end with a recommendation of Vydate because the best expert
opinion does not have a good  alternate recommendation to make. The dynamic features of the
system, however, allow that the user may actually use a different treatment, and so, any rule which
considers a  spray material that has already been applied will explicitly ask the user what, if any,
material he used.
     An interesting feature of the system is that recommendations are treated as conditions which
are always true. This allows that other conditions may follow before a given hypothesis is determined
to be true. In the above example, an additional condition is that the user accept the recommendation.
Here he rejects the recommendation, and an alternate recommendation is made after  checking a
further condition (the availability for use of Dimilin).
     The example rule belongs to a set of similar rules; each rule in that set leads to the same
hypothesis.  In the course of  a  consultation, this particular hypothesis will always be proven true,
and one and only one  rule  in its rule set will have all of its  conditions  be true. An individual
knowledge-base may contain many such hypotheses, each with its own rule set. This kind of rule
organization allows for maximum flexibility in dealing with pest interactions, user preferences, and
conditions which may vary over time (such as the availability of a particular pesticide). This flexibility
is most evident in that the rules that belong to a particular set do not have to be composed of a
uniform set of conditions. For instance, if both Spotted  Tentiform Leafminer and Rosy Apple Aphid
were a problem in a particular orchard block,  then a single pesticide recommendation would be
made to control both of these pests, and a history of Oblique Banded Leafroller damage would not
be a condition in that particular  rule since it would not affect the recommendation.
     A condition may itself represent  a set of  rules. In the example given, those conditions that
deal with  pest infestation levels are in turn dependent upon other condition sets, ones that are
made up of block characteristics, past pesticide use, and results of samples taken to determine the
density of the pest in question. Just how that information is gathered will be described in the next

     It should be noted that this example is a logical rendering of the state of the system  after its
hypothesis has been proven. Actual implementation details are different in some small respects,
and will not be discussed here since they would unnecessarily complicate the description and might


obscure our view of the logical situation. Procedural details (that is, the operation of the inference
engine) are best summed up by saying that the system considers the conditions in the order in which
they appear, and that alternate rules contain the alternate evaluations of those conditions which are
necessary to arrive at a recommendation. The overall operation of the inference engine as it works
its way through the whole system (a collection  of hypotheses and associated rule sets) will not be
described here.

    2) A User Interface. The user  of this system sees a series of pre-designed screens.  These
screens are displayed on the computer and consist of  text and graphic images. The only data
actually typed  into the system is a block name that is used to index data written to a database and
can be used by the  system at a later time. All other information is supplied by selecting labeled
boxes on the screens. The screens are of three types: data entry; instruction and illustration; and
recommendation and explanation.

    Whenever the system needs information that it can not deduce or that has not been previously
entered, it displays a screen that will be  used to obtain the data from a user. The screen will ask the
user to supply the necessary information, and it will display all the alternatives that the system
recognizes. The user's only choice  is to choose one of those alternatives via the "point and click"
operation of a mouse system. Care has been taken to include all reasonable alternatives, and to
include such options as "unknown"and "other"to take care of those  cases where the user does not
know the information,  or knows a  different alternative than those that were considered by the
system's designers.  The system  can accept such catchall  alternatives by converting them  into
default values, ones that usually represent the most conservative interpretation of the condition.
The advantage of such a closed system for eliciting  information from the user is that the chance for
minor errors such  as spelling inconsistencies  or typing  errors are eliminated. While such  minor
errors might pass unnoticed between human beings, they would of course be catastrophic  to the
system, which believes that "lannate"is always "lannate"and never "lanate".
    While  eliminating  mechanical errors is  important to the smooth operation of the system, it is
even  more  important to insure that the alternative chosen by the user does indeed reflect the state
of the orchard block. In order to assist the user in choosing the correct alternative, instruction  and
illustration screens are provided. In some cases  this is as simple  as providing a picture to show
what  an insect looks like at a particular stage in its  life cycle. In some cases, however, the kind of
information required of the user goes beyond mere identification, and involves quantitative analysis
(how  many Rosy Apple Aphids have to be present  to justify applying a pesticide, for instance). In
these cases, much more detailed instructions are  given to the user. These instructions may involve
many screens giving the user detailed instructions on how to determine the density of a pest
population. These more complicated instructions involve extensive use of hypercard and hypertext
facilities provided by the Macintosh computer  and the capabilities of the development tool.  The
user is free to move back and forth through these screens; he may browse the instructions provided,
and he may choose to read more detailed  presentations of what he does not understand. All of
these instruction and illustration screens have been implemented in the same "point and click"
fashion as previously mentioned.
    The third kind of screen belongs to the area of recommendation and explanation. When the
system has enough information, it makes a recommendation for treatment (two such recommendations
occur in the example rule above). Attached to these recommendation screens are screens which
give detailed explanations of why a  particular action is being recommended to control a particular
pest. These screens may also partially justify the  recommendation  by reminding the user of some


of the information he has previously entered in response to the system's queries. However, the
major focus of the explanation screens is not to justify, but rather is to explain the expert's reasons
for recommending a particular treatment, or perhaps, a lack of treatment. The explanation screens
attempt to address the user's concerns, and to deal with subtleties that could not be addressed in
the rules. They may, for instance, give information about the effects of the recommended pesticide
on other pests, or on certain cultivars or strains of apples. These explanation  screens attempt to
mimic a human expert by giving all those details that are not expected from a computerized system.
While the  rule system itself will only remember what value went into what slot, the user will have
access to  a great deal of additional information.
     3) Data Bases. EASY-MACS has been designed  to be consulted  at certain key times
throughout the course of a growing season. These key times correspond to various phenological
stages in the growth of apples. In addition, only a predetermined set of conditions are considered
at each growth stage. This situation has been reflected in the design of the knowledge base which
is broken up into a number of smaller knowledge bases. Each of these modules is designed to be
consulted at a particular phenological stage. Several data bases retain information generated by
consultations at successive growth stages. These databases serve as a history of the block for the
current season. They also serve as communication among the various knowledge  bases, so that
information gained at one session is available for use at a later session. For instance, the system
would like to know at the summer sessions what pesticides have been previously applied to the
block. Such information  can be useful in determining whether there  is a possibility  of the block
containing predators that feed on phytophagous mites. The presence of mite predators may in turn
obviate the need for an early summer application of a miticide. Besides serving as a communication
between  the knowledge bases,  the data bases also serve as record  keepers,  allowing us  to see
what kind of pest pressure has been encountered throughout the growing season, and how often
the system users have chosen treatments other than those recommended by EASY-MACS. Such
information can then be considered when making changes to future versions of the system.
     In the previous example information would be written to the database that would record the
recommendation of Vydate as a treatment for Spotted Tentiform  Leafminer at Pink, and that would
record that Rosy Apple Aphid was not a problem at Pink. In addition,  the data  base would  record
the fact that the user should sample for Oblique Banded Leafroller infestation at Bloom. The user
will be reminded  of this  when he consults the system  at Bloom; in the course of the same
consultation, he will be asked what spray he actually applied at Pink.


     There are many requirements that must be met prior to and during development of a KBS.
Before embarking on a KBS project,  the effort should be deemed justified and feasible.  During
development of the system it is important that an appropriate methodology be used to codify the
knowledge and that management and evaluation of the system  be considered from the start. We
will now discuss these requirements in more detail and relate them to our work on the EASY-MACS

     Developing an  expert system is an expensive and time-consuming endeavor.  A prototype
system based on a few hundred rules can often be built in a couple of months. However, it is not
unusual that a KBS requires several thousand rules and several  years to build. In addition, once a
complete KBS is developed, a final deliverable product must be produced. This will usually involve


significant product enhancement where factors such as performance, usability, documentation and
reliability come into play. This stage of the KBS effort may require two to three times the effort
required to develop the basic system (Cupello and Mishelevich 1988). As a result of development
costs, prudence dictates that a careful evaluation be made of both the justification and feasibility
of a proposed project. Waterman (1986) provides a list of criteria which should be satisfied in order
to justify the development  of a KBS and another set of criteria that can be used to assess the
feasibility of a KBS project. Prerau  (1985) also discusses criteria appropriate for determining the
feasibility of  a KBS project. We used these  criteria to evaluate whether a KBS for apple pest
management was justified and feasible. Justification for development of a KBS rests on two principal
criteria; 1) solution of the problem to be dealt with by the KBS should have a high payoff and 2)
expertise required to solve the problem dealt with by the KBS should be a scarce resource. The
goal of  the EASY-MACS system is  to provide expertise necessary to realize integrated control of
apple pests at the farm level. The desirability of IPM and potential benefits accruing from its adoption
justify the cost of developing a KBS  in this domain. It is also clear to us that in this problem domain
human  expertise is scarce. That is, there are few experts who can provide expertise required to
realize  apple IPM.  In  addition, the cost of providing human expertise  for this purpose  is high.
Concluding that  human expertise  is  scarce does not however guarantee that the  expertise
necessary  to develop a KBS exists. This is a  particularly dangerous trap to fall in, especially from
the standpoint of developing KBSs  for use in agriculture. Many of the experts to be relied on for
contributing knowledge to a KBS are principally involved in research rather than applications or are
experts in only a portion  of the complete problem domain. Therefore, the  potential exists to
overestimate the availability of the knowledge  necessary to develop the system.
     There are two principal criteria which must be met in order to conclude that expert system
development is possible. First, it must be determined that the problem to be solved is sufficiently
well understood that a solution can  be found.  As a corollary, genuine experts must exist and they
must be able to articulate the methods they use to arrive at a solution. Also, if multiple experts are
used, the experts must agree on solutions. We feel that the best way to determine that the expertise
necessary to render a solution to a problem exists is to observe this expertise in action under a
real world  setting. Thus, one year  prior to beginning development of EASY-MACS, part of the
knowledge to be encoded in the system was  put into practice under the guidance of some of the
experts to be used in system development. Essentially we were asking whether an expert's
performance on this problem was measurably  better than that of an inexperienced individual. While
this did not ensure that all  the expertise required would be available, it  did provide us with some
assurance that a reasonable knowledge base  existed.
     The second criteria that must be met in order to conclude that KBS development is possible
is that the task to be addressed should not be too  difficult nor should it  be too simple. Whether a
task is so simple that a KBS is unnecessary can usually be ascertained. If a task is simple it should
be possible to write down instructions that are to be carried out in order to complete it. If this can
be done, then a KBS is not necessary. Whether a task is too difficult for a KBS solution is more
difficult  to determine. Some insight in this regard can by obtained by determining whether the
problem domain is reasonably bounded. In other words, can the extent of the knowledge  required
to solve the problem be delimited or is a vast array of knowledge required that resides outside of
the boundaries of the problem. Another strategy is to develop a prototype system to test the concept
of building a more complete system.

     KBS's are unlike many other computer programs in that the  gathering of knowledge for
inclusion in them tends to be harder and more important than the actual coding of the system.
Typically, KBS's are constructed by a team consisting of an expert, a knowledge engineer and a
programmer (the same person may serve the latter two functions). The role of the knowledge
engineer is to elicit the knowledge of the expert through a series of interviews and state it in a form
amenable to  computer codification. Furthermore, a rapid prototyping methodology is frequently
advocated (Waterman 1986). This approach places an  emphasis on rapidly achieving a working
system, even if only a simplified one, rather than on design and specification. A system may have
to be discarded and rewritten many times before the final program is arrived at. The main advantage
of this method is that it is often difficult to specify a KBS in advance; the process itself  assists in
arriving at the specification. However, this  reasoning has  probably been taken too far. For example,
McKinion and Lemmon (1985) state that through the use of a rapid prototyping methodology, system
developers can explore ill-specified, ill-understood,  and changeable  requirements  and that a
problem does not necessarily have to be well understood  in order to be  amenable to a KBS solution.
We strongly feel that this is not true. Taken to this extreme, the rapid prototyping approach is likely
to produce an inconsistent and incomplete knowledge base. In short a system produced using this
methodology is not likely to be reliable (Denning 1986).
     There are at least two good reasons not to follow this paradigm for KBS development explicitly.
In the EASY-MACS project we departed from this paradigm by using a team of experts that included
an  individual who was knowledgeable  about KBS technology and apple IPM and by employing
some more conventional software engineering methods.
     The first reason for not using the frequently cited development model centers on codifying the
knowledge to be placed in the system.  IPM knowledge is rather diffuse, that is experts are usually
knowledgeable in  rather limited sub-fields and in the areas where experts overlap they often don't
agree. Thus, to develop EASY-MACS a team of experts was  used that met as a group and were
required to come  to consensus concerning the knowledge to be incorporated into the KBS. The
process of consensus was difficult and only worked because a project coordinator was available
who could serve as an intermediary. This individual was a expert in the field, but also was familiar
with computers and their requirements for  knowledge representation and manipulation. The second
reason for using the team of experts centers around articulating the knowledge to be placed in the
KBS. Parnas (1985) has argued that a trial and error approach to eliciting knowledge for use in a
KBS is likely  to produce an incomplete  and inconsistent  knowledge base and that instead of
examining how people (experts) solve problems,  attention should be devoted  to studying  the
problem itself. An  expert may not know why a particular  method works and a knowledge engineer
may not ask the right questions which will allow an expert to articulate his methods. We found that
by using a team of experts considerable attention  was devoted towards studying the problem itself
and as a result, a more consistent and complete knowledge base was  developed.
     EASY-MACS is not a typical system in that  it deals with a series of consultations over time
rather than a single session. This immediately suggested using a modular design and incorporating
a system 'memory' (data base). Each of the smaller knowledge bases could have sub-goals of their
own, which would contribute to the problem solution. Also, their organization could differ (inasmuch
as the development tool would allow) to reflect their particular purpose. The memory would allow
the  system to refer to what treatments and infestations had occurred previously, as a real expert

    Thus because of the nature of the problem being tackled and because of misgivings about the
rapid prototyping methodology, a rapid prototyping philosophy was used, but imposed on it was a
modular organization, so only small parts of the system were under development at any one time.
This modular approach  allowed us to keep the individual knowledge-bases small, which makes
them more comprehensible and easier to maintain. It also allowed us to use a more conventional
software development strategy wherein specifications about the modules were determined prior to
actual coding.

     The final point to be considered in this section is that of evaluation of the system. Excellent
reviews of this topic are presented by Cupello and Mishelevich (1988) and  O'Keefe et al (1987).
Therefore, we will focus only on one important point and relate them to our work on EASY-MACS.
We feel it is very important to evaluate a KBS both for correctness and  usability  early in the
developmental cycle. Although EASY-MACS is still in an early phase of development, we feel it is
important to allow potential users  access to it. Thus we have provided copies (and computers) to
several apple growers. The information  gained from them will be incorporated into the next test
system to be distributed.

     We have already obtained some useful advice from our trial users. One point that has become
obvious is that dynamically constructed screens need to be added to the interface. This is necessary
in order to provide a more useful  explanation of the reasoning process employed by the system
when arriving at a recommendation. Since this is beyond the capabilities of our development tool,
we are required to code these ourselves. Another, unexpected, problem involves the knowledge
itself. Users desired access to the expertise in the system at  other times and in other ways than
during consultations designed to  provide a management recommendation.  For example, a user
might be interested in querying the system to determine the toxicities of various insecticides to mite
predators. The  current system does not  allow this, nor could it without a major redesign, such as
going to an object-oriented programming  environment, rather than a rule-based one. This last point
is not trivial because a major difficulty in developing KBS's is to express knowledge about a problem
without committing to a particular way of  using it.
     We  also watched fruit growers use the system, which was, in effect,  an evaluation of our
presentation  method. Their choice of which screens to read and which to skip showed us that the
examples chosen were not always the most relevant ones, and that certain facts must be included
in every possible path through the system, including highly unlikely ones. This will insure that certain
information is presented, but can not guarantee that it will be read, understood or acted upon.

                                PITFALLS TO AVOID

     When a nascent technology is embraced by a  new discipline  it is  often  surrounded by
misunderstanding and overly ambitious claims about its potential. This is certainly true with respect
to KBS's and IPM. The danger here is that when the technology fails to meet its advertised potential,
it is prematurely judged ineffective  and inappropriate. To guard against this it is important that those
who may use the technology or who evaluate tools produced by it be  aware of pitfalls that may
befall them. Towards this end we have constructed the following list.
1)  KBS's, especially those with  sophisticated graphical interfaces, are inherently high-tech and
impressive. However, like any computer program, they only function as well as their design and
content allow. The temptation to present  in this format ideas we are not certain of is great, for they


are likely to be accepted solely due to the manner of presentation. We must be sure to produce
only systems that incorporate what we know, not ones that present what we would like to know.
2)  The  amount of work involved in EASY-MACS, a relatively small system,  is immense and
inherently long-term. It is  essential  that other projects  of this type  not be undertaken  unless
adequate, long-term resource commitment (personnel and equipment) is insured. Coordinate with
this is recognition of the value of this type of activity for the participants, something which may be
difficult at a traditional, research-oriented institution.
3)  Are our expectations about KBS realistic? These systems do not think and only seem to display
any type of intelligence. In  reality, KBS use programmed  rules of inference to reach a conclusion.
They manipulate symbols, but in a context free situation and without any understanding of what the
symbols mean. A KBS is constrained by the knowledge it contains and can not reach conclusions
that are  not implicit in that knowledge. Most KBS can not detect faulty data or if they are being
employed for a problem not in their domain. In either case, answers will be provided, but almost
certainly they will be incorrect, and the user is more apt to blame the system then themselves.
4)   Is thought being given to ensure that a KBS is consistent and complete? A  trial and error or
case study approach to eliciting knowledge may produce an incomplete and inconsistent knowledge
base. This type of software  is likely not to  be  as  reliable  as that developed  from precise
specifications. The system may well reproduce any errors the expert would make. The designer
and user may well disagree at to whether this is a feature or a fault of the system.
5)  Are we using the elicited knowledge effectively? Knowledge encoded in rules, by far the most
common representation in  KBS's, can only be accessed in a manor consistent with the way the
inference engine manipulates the rules. That is, certain questions may be answered, but others can
not be, even though the knowledge to answer them is in  the system. This is because the form of
the system itself limits the  ways the knowledge can be accessed. If knowledge was encoded as
facts, multiple access paths would be possible, but coding would become much more difficult. Until
tools are developed to assist the KBS developer in this form  of knowledge representation, we will
continue to waste the very resource we are trying to conserve, expert knowledge.


     In this final section of  the paper we list five conventional opportunities and benefits of KBS's
and then discuss what we feel is the most fundamental opportunity for use of KBS in IPM. There
are  a  number of  important advantages  of KBS's  compared  to  conventional text-based or
computer-based decision aids that are often  cited. First, the information base not only consists of
objective information (published technical data) but also  includes  expert opinions on issues and
problems not necessarily addressed by such information. Second, KBS's  provide a format for
dealing with imprecise or incomplete data, precisely that with which a real expert must often contend.
Third, because a KBS can record its logical chain  of reasoning, it has explanatory power, although
it should  be noted that providing such explanations in a form a user can comprehend is not a trivial
task. Fourth, little technical expertise is required to use the system. Finally, interactive graphics can
provide a visual display of information for diagnostic and educational purposes, thereby improving
the usefulness of the system and increasing the user's confidence in the system's recommendations.
     The fundamental opportunity in the use of KBS's is to deliver IPM related knowledge in a form
that will facilitate its use. It is important though to address this opportunity in the proper framework.


We do not think it is appropriate to ask "how can we build a system that will behave like an expert
solving a pest management problem". The reason for this is that KBS's use rationalistic problem
solving; given a precise statement of a situation they enumerate alternatives for solution and find
the best solution based on some objective criteria. However, this type of problem is only a partial
description  of  how people solve problems. A person processes data within a framework of
interpretation whereas a KBS does not. As a result, it is more appropriate to ask "how can KBS's
be designed to help people do things more effectively". If this is kept in mind KBS's will likely make
a significant contribution to the adoption of IPM practices.

                                     REFERENCES CITED
 Coulson, R. N., and M. C. Saunders. 1987. Computer assisted decision making as applied to entomology. Ann. Rev.
         Entomol. 32:415-438.
 Cupello, J. M. and D. J. Mishelevich. 1988. Managing prototype knowledge/expert systems projects. Commun. ACM.
 Davis, R. 1986. Knowledge-based systems. Science. 231:957-963.
 Denning, P. J. 1986. The science of computing - expert systems. Am. Sci. 74:18-20.
 McKinion, J. M. and H. E. Lemmon. 1985. Expert systems for agriculture. Comput. Electron. Agric. 1:31-40.
 Naegle, J. A., R. N. Coulson, N. D. Stone, and R. E. Frisbie. 1986. The use of expert systems to integrate and deliver IPM
         technology. In Integrated Pest  Management on Major Agricultural Systems.  R. E. Frisbie and P. L. Adkisson
         eds. Texas A & M University.
 O'Keefe, R. M., O. Balci, and E. P. Smith. 1987. Validating expert system performance. IEEE Expert. Winter 1987:81-89.
 Parnas, D. L 1985. Software aspects of  strategic defense systems. Am. Sci. 73:432-440
 Prerau, D. S. 1985. Selection of an appropriate domain for an expert system. Al Magazine. 7,2:31-40.
 Waterman, D. A. 1986. A Guide to Expert Systems. Addison-Wesley, Reading, MA.
 Wearing, C. H. 1988. Evaluating the IPM implementation process. Ann. Rev. Entomol. 33:17-38.



                          LIST OF CONTRIBUTORS
       Department of Agronomy
       University of Maryland
       College Park, MD 20742
       Toxicology and Mycotoxins Research Unit
       Richard B. Russell Agricultural Research Center
       P.O. Box 5677
       Athens, GA 30613

       Department of Plant Pathology and Weed Science
       Colorado State University
       Fort Collins, CO 80523
       Department of Plant Pathology, Entomology and Agronomy
       University of Kentucky
       Lexington, KY 40546-0091

       New Jersey Agricultural Experiment Station
       Rutgers University
       New Brunswick, NJ 08903

       Department of Entomology
       Colorado State University
       Fort Collins, CO 80523
       Department of Entomology
       University of Kentucky
       Lexington, KY 40546

       Departments of Plant Pathology, Entomology and Agronomy
       University of Kentucky
       Lexington, KY 40546-0091

       Departments of Botany and Plant Pathology, and the Pesticide Research Center
       Michigan State University
       East Lansing, Ml 48824

       Department of Entomology
       University of Maryland
       College Park, MD 20742

        Department of Agronomy
        University of Maryland
        College Park, MD 20742

        Departments of Botany and Plant Pathology, and the Pesticide Research Center
        Michigan State University
        East Lansing, Ml 48824

        New Jersey Agricultural Experiment Station
        Rutgers University
        New Brunswick, NJ 08903

        The Davey Tree Expert Company
        1500 North Mantua Street
        Kent, OH 44240

        1057 East Meadow Circle
        Palo Alto, CA 94303

        Departments of Natural Resources Sciences and Plant Sciences
        Rhode Island Agricultural Experiment Station
        University of Rhode Island
        Kingston, Rl 02881
        Board of Supervisors
        70 W. Hedding St.
        San Jose, CA 9510
        Department of Agronomy
        University of Maryland
        College Park, MD 20742

        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson, NJ 08077

        Department of Agronomy
        University of Maryland
        College Park, MD 20742

        IPM Program
        New York State Agricultural Experiment Station
        Cornell University
        Geneva, NY 14456

HULL, R. j.
        Departments of Natural Resources Sciences and Plant Sciences
        Rhode Island Agricultural Experiment Station
        University of Rhode Island
        Kingston, Rl 02881
        New Jersey Agricultural Experiment Station
        Rutgers University
        New Brunswick, NJ 08903
        O. M. Scon and Sons Co.
        Research Division
        Marysville, OH 43041

        Horticultural Insects Research Laboratory
        Application Technology Research Unit
        Ohio Agricultural Research and Development Center
        Wooster, OH 44691

        Texas A&M University
        Research and Extension Center
        17360 Co it Road
        Dallas, TX 75252

        R & D Dept.
        Soil Technologies Corp.
        600 North 12th Street
        Fairfield, IA 52556
        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson, NJ 08077

        U. S. Environmental Protection Agency
        Office of Pesticide Programs
        Field Operations Division (H7506C)
        401  M Street, S.W.
        Washington, DC 20460

        Department of Entomology
        University of Illinois
        Urbana, IL61801

        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson, NJ 08077

        Department of Entomology
        University of Kentucky
        Lexington, KY 40546

        Department of Entomology
        New York State Agricultural Experiment Station
        Cornell University
        Geneva, NY 14456

        Departments of Botany and Plant Pathology, and the Pesticide Research Center
        Michigan State University
        East Lansing, Ml 48824

        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson,  NJ 08077

        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson, NJ 08077

        Department of Entomological Sciences
        University of California
        Berkeley, CA 94720

        Department of Entomology
        University of Kentucky
        Lexington, KY 40546

        Jefferson County Cooperative Extension
        Golden,  CO 80401
        Department of Entomology
        University of Maryland
        College Park, MD 20742

        Agri-Diagnostics Associates
        2611 Branch Pike
        Cinnaminson,  NJ 08077
        Departments of Botany and Plant Pathology, and the Pesticide Research Center
        Michigan State University
        East Lansing, Ml 48824

        R & D Dept.
        Soil Technologies Corp.
        600 North 12th Street
        Fairfield, IA 52556

        ChemLawn Services Corporation
        Research and Development
        P.O. Box 85-816
        Columbus, OH 43085
        Departments of Plant Pathology, Entomology and Agronomy
        University of Kentucky
        Lexington, KY 40546-0091
        Department of Entomology
        University of Maryland
        College Park, MD 20742

        Departments of Natural Resources Sciences and Plant Sciences
        Rhode Island Agricultural Experiment Station
        University of Rhode Island
        Kingston, Rl 02881

        Departments of Botany and Plant Pathology, and the Pesticide Research Center
        Michigan State University
        East Lansing, Ml 48824

        Department of Entomology
        New York State Agricultural Experiment Station
        Cornell University
        Geneva, NY 14456
        Grounds Maintenance  Magazine
        P.O. Box 12901
        Overland Park, KS 66212;
        formerly, Department of Agronomy,
        University of Maryland
        College Park, MD 20742

        O. M. Scott and Sons Co.
        Research Division
        Marysville, OH 43041

        Professional Lawn Care Association of America
        101 Buena Vista Drive
        North Kingston, Rl 02852

        Department of Computer Science
        Rochester Institute of Technology
        Rochester, NY 14623

        Department of Entomology
        University of Nebraska
        Lincoln, NE 68583

•k U.S. GPO: 1989—625-030                                                                                 °°'