WASHINGTON, D.C. 20460



Acknowledgments 	     1
Preface	     I
Introduction  	     2
Major Crops	     2
  Feed Grains and Small Grains	     2
  Hay and Pasture	     3
  Fruits and Nuts	     3
  Vegetables  	     4
  Specialty Crops 	     4
Pests  	     4
  Insects and Mites 	     5
    Thrips  	     5
    Grasshoppers and Crickets	     6
    True Bugs 	     6
    Aphids and Psyllids 	     6
    Leafhoppers, Spittlebugs (Froghoppers) and Treehoppers ....     7
    Scales  and Mealybugs	     7
    Whiteflies	".	     8
    Moths and Butterflies 	     8
    Beetles 	    10
    Flies, Gnats, and Midges	    13
    Sawflies  	    13
    Mites  	    13
  Plant Disease Agents 	    14
    Fungi  	    14
       Leaf Diseases 	    14
       Wilts, Root Rots, and Crown Rots	    15
       Stem Cankers 	    15
      Fruit Rots 	    16
      Seed and Seedling Diseases 	    16
                   EPA Es^d.i'-i:.--1. ---  *--••*•-

     Bacteria	     16
       Bacterial Wilts	     16
       Bacterial Blights, Leaf Spots, and Rots	     16
       Bacterial Galls and  Overgrowth	     17
     Viruses and Mycoplasmas	     17
     Nematodes	     17
     Parasitic  Seed Plants	     18
   Snails and Slugs	     18
   Weeds  	     18
     Development Stages 	     19
     Weed Classification 	     19
       Grasses	     20
       Broadleaves  	     20
     Factors Affecting Control	     20
     Determining the Weed Problem	     21
     Weed Control Methods	     21
   Vertebrate  Pests  	     22
Pesticides	     22
   Insecticides   	     22
   Miticides  	     22
   Fungicides   	     23
   Bactericides  	     23
   Controlling  Viruses and Mycoplasmas	     23
   Nematicides  	     23
   Controlling  Parasitic  Seed Plants  	     23
   Molluscicides	     23
   Herbicides   	     24
   Controlling  Vertebrate Pests	     26
Environmental Protection 	     27
   Soil  and Water 	     27
   Drift	.'	     27
   Reentry and Preharvest Intervals  	     28
   Phytotoxicity 	     28
   Community  Problems	     29


   This  guide  has been developed by  the  Program
 Support Branch, Operations Division, Office of Pes-
 ticide Programs, Environmental Protection Agency.
 Much of the information  was drawn from materials
 published by the Cooperative Extension Services in
 several  States;  the U.S. Department  of Agriculture;
 and other sources. The Agency extends its apprecia-
 tion to  these sources and also to the many persons
 throughout the country who reviewed the manual at
 various  stages  and whose valuable comments con-
 tributed greatly to its preparation.

  Federal regulations  establish general and specific
standards that you must meet before you can legally
use certain pesticides. Your State will provide mate-
rial which you may study to help you meet the
general standards. This guide contains basic informa-
tion to help  you meet  the specific standards for ap-
plicators  who are engaged  in agricultural plant pest
control. Because the guide was prepared to cover the
entire Nation, some information important to your
State  may not  be included.  The  State  agency  in
charge of your training can provide the other mate-
rials you should  study.


   Pesticides  are a valuable  tool for profitably pro-
ducing a high-yield, market-acceptable crop, but they
should be used only when and where they are needed.
Usually  pesticides  should be used only when pest
numbers and/or the pest problem has reached the
economic threshold  and other pest  management
methods do not provide effective control. In some
cases, preventive use is a necessary, cost-effective way
to protect crops.  Protectants should be  used  only
when knowledge of the pest indicates it is necessary.
You should be  familiar with alternatives to the use
of pesticides and inform your customers about them.
Be sure they know the possible consequences of both
pesticide use and the use of alternative  control meth-
   Sometimes a producer asks you to apply a specific
pesticide on a crop. At other times you are asked to
both diagnose a pest problem and to provide control.
Accurate detection, identification, or diagnosis is a
science. Experience is important. This manual is not
intended to make  anyone an expert in identifying
pests  on crops or in  selecting the proper control
technique. However,  you should be able to identify
the more common  pests that  attack agricultural
crops. When  you find  a  pest or pest  problem you
cannot identify, ask an expert to help you.

              Integrated Control
  This manual discusses some of the general produc-
tion practices that may increase or lessen pesticide
problems.  You will be a better applicator if you un-
derstand these basic principles.
  You as  an  applicator should:
    • understand  crop  production  and cropping
    • be able to identify common pests and signs
       and/or symptoms  of the damage they cause,
    • have basic knowledge of the chemical charac-
       teristics and the mode of action of pesticides,
    • understand application techniques and equip-
       ment use,
    • recognize pesticides'  potential for injury  to
       people, pets, livestock, and the environment,
    • know  and follow the safety practices essential
       for protecting yourself and  your employees,
       the  producer  and his employees, the con-
       sumer, and the  environment.
             MAJOR  CROPS
 Feed  Grains  and  Small  Groins

 Crop Characteristics
   These widely grown crops are summer or winter
 annual grasses. In  the past, seedbed preparation us-
 ually included complete removal or incorporation of
 the previous year's crop residue. This practice con-
 tributes to wind  and water erosion of soil particles
 and the attached pesticides. No-till seeding is becom-
 ing more common. It  minimizes  erosion and may
 simplify  weed control, but  its  impact on  disease,
 rodent, and insect  control  is not known.
   These crops have a relatively low unit value. As a
 result, per acre pest control costs must be kept low.
 Resistance to  several common diseases and insect
 pests is good in some of the more popular crop varie-
ties. Certain cultural control practices  may reduce
 the need for pesticides. These include:
     •  no-till seeding,
     •  moldboard plowing,
     •  cultivation,
     •  crop rotation,
     •  planting date and  harvest date timing, and
     •  special harvest and storage methods.
 These methods may be used alone or in combination.

   Many producers use pesticides preventively to con-
trol  some soil-infesting insects such as wireworms,
plant disease agents such as nematodes, and weeds
such as pigweed and foxtail.
   Machines are widely used in the production and
harvest of these crops. This lessens worker exposure
to pesticide residues. However, these crops are used
as food or feed, so  be sure to inform your customer
of the limitations on the time between pesticide ap-
plication and harvest, slaughter, or grazing.
  Many types of low-pressure field sprayers are used,
ranging in  capacity from 50 gallons  to  more  than
1,000 gallons. They can do many highly specialized
       Low Pressure Field Sprayer
                                  Granular Applicator
  Dry formulation application equipment also comes
in a wide variety of sizes and capabilities.
  Aircraft can be specially adapted for the different
applications of pesticides to these crops.
 Hay  and  Pasture

 Crop Characteristics
   These widely grown crops include:
     •  intensively  cultivated  alfalfa,  clover,  and
        grasses introduced in most parts of the coun-
       try, and
     • native grasses and broadleaved plants grown
       with a minimum of cultivation.
   Resistant varieties, harvest timing, and other non-
chemical control practices such as burning are espe-
cially useful  in pest  control  in  hay  crops.  Hay
producers often use fall seeding, or plant with spring-
seeded small grains as a nurse crop to control weeds.
Without insect- and  disease-resistance, alfalfa  could
not be grown  over much of its present range in the
United States.
   Since all hay and pasture crops  are used for live-
stock feed, it is essential to obey time limitations be-
tween pesticide application and grazing or harvest.
Especially restrictive  residue tolerances apply to milk
and dairy products.

   Pesticides are usually applied to hay and pasture
crops with  low-pressure  boom  sprayers or aircraft
equipped to apply both liquid and dry formulations.

 Fruits  ond  Nuts

 Crop Characteristics
   Small fruits include such crops  as grapes, bram-
bles, blueberries, strawberries, and  cranberries. Tree
fruits include such crops  as  apples, peaches,  pears,
citrus, cherries, and  plums. Nuts include such crops
as walnuts,  almonds, and pecans.
   Highly sophisticated pest control practices are used
on fruits  grown for human  consumption. In some
situations, the crops  are closely monitored for pests,
If pests are  found, pesticides may be recommended.
The surface appearance of  fruits  grown for fresh
market has  long been critical to the producer. To
produce blemish-free fruit, the producer sometimes
must use pesticides preventively on a schedule modi-
fied only to  adapt for variable weather.
   Many fruit crops must be harvested by hand labor.
Hand labor is also required to prune fruit trees  and
to thin some crops  selectively during the growing sea-
son. Pesticide labels specify  time  intervals between
pesticide application and reentry or harvest. These
directions are  critical and must be obeyed. The  law
requires applicators  to inform  their customers  and
employees of these intervals.
   Two or more pesticides often are applied in com-
bination. Pesticides may also be combined with fer-

 tilizers. The applicator must pay strict attention to
 their physical and chemical compatibility. The label-
 ing on chemical products sometimes identifies prob-
 lems of incompatibility.  Follow label instructions
   Many of these crops are perennial and may remain
 in place for decades. Pesticides may persist on or-
 chard or vineyard soil from repeated use. Local ex-
 perts are aware of potential residue problems. They
 can help you.


  Equipment most often used on  these crops  in-
     • air  blast  sprayers with fixed  or movable
     • high-pressure sprayers with fixed or movable
     • dusters,
     • hand-held booms, and
    • aircraft.
            High Pressure field Sprayer
                                    Air Blasl Sprayer
                                    or Mist Blower

 Crop Characteristics
   In general, these are intensively cultivated annual
 plants, the fruits, stems, leaves, or roots of which are
 used as  human or livestock food.  Vegetables, like
 tree fruits, are expected by the consumer to have a
 blemish-free appearance.  Since the  edible portions
 of most of these crops are produced  under an inten-
 sive schedule of pesticide application, worker reentry
 and pre-harvest intervals are critical to protect field
 workers, harvesters, and consumers.
   Resistant varieties  and cultural control methods,
 including selective planting and harvesting dates and
 destruction or removal of cultivated crop residue, are
 an important part of pest control on  vegetables.

  Pesticide application equipment most  often used
on vegetables includes:
     • fixed- and movable-head air blast sprayers,
     • high-  and low-pressure boom sprayers,
     • dusters,
     • granular applicators, and
     • aircraft.

 Specialty Crops

 Crop Characteristics
   Specialty crops include cotton, soybeans, tobacco,
 sugar beets, sugar cane,  and  peanuts. Most are row
 seeded  and managed  much  the same as the  feed
 grains and small grains. Some of these crops,  such
 as  cotton  and soybeans, require extensive use  of
 pesticides for successful production.  Other specialty
 crops, such as sugar beets and  sugar cane, can be
 produced almost without the  use of pesticides.

  Pesticide application equipment most often used
 on  these crops is low-pressure boom sprayers  and
 aircraft-mounted  sprayers.


    The first step  in solving any problem is to under-
 stand what is causing it. So the first step in your job
 is to recognize the pests you  need to control.
    We favor certain plants and animals that provide
 us food and fiber. But we also provide good growing
 conditions for other  plants  and animals  that harm
 them. These living things that compete with us for
 food and fiber, or attack us  directly, are pests. The
 living plant or animal a pest  depends on for survival
 is called the host.
    Pests can be put into five main groups:
      •  insects (plus mites, ticks, and spiders),
      •  plant disease agents,
      •  snails and slugs,
      • weeds, and
      •  vertebrates.
   Most applicators know most of the pests they see
 on the job. But sometimes unfamiliar pests may ap-
 pear. You can get identification aids, publications,
 and pictures to help find out  what they are.  But the
 best thing to do is to contact local experts. Ask the
 Cooperative Extension Service or a competent  con-
 sultant to help you.

Insects  and  Mites
  The large  number of insects,  mites,  and related
animals can be divided  into three categories accord-
ing to their importance  to man:
     • species which are of only minor importance
       —About 99 percent of all species are  in this
       category. They  simply "take up space" and
       supply food for birds, fish, mammals, reptiles,
       amphibians, and other insects. Some have es-
       thetic value.
     • beneficial insects and mites—In this small but
       important group are the predators and para-
       sites that feed on destructive insects,  mites,
       and weeds. Examples are lady  beetles, some
       bugs, ground beetles, tachinid flies, many tiny
       parasitic wasps,  and predaceous mites. Also
       in this  category are  the  pollinating insects,
       such as bumblebees and honeybees,  some
       moths,  butterflies, and beetles.  Without pol-
       linators, many fruits, vegetables, and  forage
       crops could not  be produced.
     • destructive insects and mites—Although this
       is the category which usually comes to mind
       when insects are mentioned, it  includes the
       smallest number of species. In this  category
       are certain  species of thrips,  grasshoppers,
       true bugs, aphids, leafhoppers,  scales,  white-
       flies, moths, beetles, flies,  sawflies, and mites
       that feed upon food and fiber crops.

                 Insect Damage
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                                                        Four Wings
                                                   Thrips  are  thin,  tiny insects  with four  narrow
                                                 fringed wings  in the adult  stage. During their life
                                                 cycle they change gradually in size and  slightly in
                                                 form from egg  through several  wingless nymphal
                                                 stages to winged adults. Several generations are pro-
                                                 duced each year. Both nymphs and adults have tube-
                                                 like mouthparts  and feed on plants by rasping the
                                                 surface tissue  of tender buds, flowers,  fruits,  and
                                                 leaves,  then sucking the plant juices (sap).
                                                   Injury to plants is  characterized by discolored and
                                                 distorted flowers and buds or grey speckled areas on
                                                 fruit and foliage. Thrips may attack  every type of
                                                 agricultural crop. Common  species are:
                                                     •  bean thrips on legumes,
                                                     *  citrus thrips,
                                                     •  flower  thrips on  grasses,  vegetables,  and
                                                     •  onion thrips on  onion and other vegetables,
                                                     •  tobacco thrips.
                                                                  GLADIOLUS THRIPS

 Grasshoppers  and  Crickets
   Grasshoppers and crickets are large-bodied insects
 with hind legs adapted for jumping. During their life
 cycle they change gradually in size and  slightly in
 form from egg through several wingless nymphal
 stages to winged or wingless adults. Usually there is
 only one generation produced each year. The eggs
 overwinter in the soil. Both nymphs and adults have
 toothed (chewing) mouthparts which they use to cut
 small sections from leaves and stems of plants.
   Injury is characterized by ragged holes in foliage
 and  stems.  In  large  numbers,  grasshoppers and
 crickets may consume all of a plant or plants in an
 area. Grasshoppers and crickets may attack  every
 type  of agricultural crop.  Common species include
 Mormon cricket, mole cricket, field cricket, migra-
 tory grasshopper, and two-striped grasshopper.

 True   Bugs
   Pest  species of  true bugs in the adult form have
 two pairs of wings. The  first pair is leathery at the
 base  and nearly transparent  at the tip. At rest, the
 wings lie flat across the thorax and abdomen with
 the transparent tips overlapping. During their life
 cycle true bugs change gradually in size and slightly
 in form from egg through several wingless nymphal
 stages to winged adults.  One to several generations
 are produced each year. Both nymphs and adults
 have tubelike (piercing-sucking) mouthparts and feed
 on plants by puncturing seeds, stems, foliage, flowers,
 or fruit and sucking the  sap. Some true bugs may
 inject a toxin into the plant which  causes further
  Injury to plants is characterized by  mottled grey
 spots  on foliage, deformed  buds or fruit (catfacing),
loss of  vitality, wilting, and—in severe infestations
—death. Some plant disease agents are carried  by
these  insects. True bugs  may attack many kinds of
fruit,  vegetable and grain crops.

 Common species include:
   • chinch bug—corn and grain crops,
   • harlequin bug—crucifers,
   • stinkbug—vegetable crops,
   • squash bug—vine crops, and
   •  tarnished plant bug—vegetables and fruits.
                           HARLEQUIN  BUG
                         ADULT  AND NYMPH
Aphids  and  Psyllids
   Aphids and psyllids, called plant lice and jumping
plant lice, are small, soft-bodied insects usually less
than V4 inch long. In the adult form they usually have
transparent wings which are held vertically over the
body when at rest. During their life cycle they change
gradually in size  and  slightly  in  form from egg
through several wingless nymphal stages to winged
and  wingless  adult  stages.  Many  generations are
produced each year. Both nymphs  and  adults have
tubelike mouthparts and feed on plants by puncturing
tender plant parts and sucking the sap.
   Injury to the plant is characterized by loss of plant
vigor, stunted and deformed buds  and flowers, or
curled and puckered foliage. Plant lice and jumping
plant lice secrete honeydew which attracts ants and
upon which unsightly sooty mold grows. Aphids also
transmit some viral, bacterial, and other plant disease

   Common aphid species include:
     • grape phylloxera,
     • the greenbug—grains,
     • green peach aphid—tobacco, peaches, pota-
        toes, spinach,
     • melon aphid—melons, cotton, fruits, vegeta-
     • potato aphid—potato, tomato, and
     • apple aphids.
   Common psyllids are:
     • potato psyllid—potato and tomato, and
     • pear psyllid.

 Leafhoppers,  Spittlebugs
 (Froghoppers)  and  Treehoppers
   Leafhoppers, spittlebugs and treehoppers are small
 (usually not over 1A  inch long), soft-bodied insects
 with hind legs adapted for jumping. The adults have
 two pairs of transparent wings held in a rooflike posi-
 tion  when at rest. During the life cycle they change
 gradually  in  size  and slightly in form  from egg
 through several wingless nymphal stages to winged
 adults. Many generations are produced each year.
 Both nymphs and  adults have tubelike mouthparts
 and feed on plants by  piercing leaves and stems and
 sucking the sap.
   Injury to the plant is characterized by mottled, dis-
colored, and  curled leaves,  and stunted  or wilted
 stems. 'Spittlebug nymphs are easily identified by the
 foamy  spittle mass which surrounds  and protects
 them during feeding. All these hoppers may transmit
plant disease agents, especially those agents causing
 yellows, stunt, and curlytop.
   Some  leafhoppers secrete  honeydew,  which at-
tracts ants and supports the growth of unsightly sooty
mold. Other leafhoppers inject a toxin  into the plant
during feeding, causing a browning  of leaves called
"hopper  burn." Treehoppers damage plants by slit-
ting the bark or stem to deposit their eggs.
   Common species include:
     • buffalo treehopper—tree fruits,
     • alfalfa hopper,
     • meadow  spittlebug—strawberries,  legumes,
       forage crops,
     • aster leafhopper—lettuce, celery, other vege-
       tables, grains,
     • potato leafhopper—potato, legumes, apples.

Scales and  Mealybugs
   Scales  and mealybugs are small, oval insects which
resemble reptile scales or tiny  bits of wax or wool.
They may be mistaken for parts of  the plant itself.
Mealybugs  are soft-bodied scales covered with white
powder and often with cottony fibers. Scales may be
soft-bodied or armored  with  a crusty shell. Adult
females are wingless and usually stationary, but adult
males resemble tiny flies with a single pair of wings.
   During the life cycle they change gradually in size
and slightly in form from egg through  several wing-
less nymphal stages and a pupalike  stage  to adults.
Many generations  are produced each year. Adult
males do not have mouthparts and do  not feed.
Nymphs  and  adult females have very long, slender,
tubelike mouthparts. They feed on plants by sucking
sap from plant stems, leaves, and branches.
                                                         San Jose Scale: (A) Adult Female Scale; (B) Male Scale;
                                                         (C) Young Scales; (0) Nymph (Crawler)

   Injury  is characterized  by  stunted,  yellowed,
 wilted,  and often deformed growth.  Scales  and
 mealybugs also  transmit some plant disease agents
 and secrete large  amounts of honeydew,  which at-
 tracts ants and supports unsightly sooty mold. Large
 quantities of sooty mold on crops usually indicates
 an aphid  or scale  infestation. Mealybugs and scales
 may attack many kinds of fruit, vegetable, and espe-
 cially greenhouse crops.
   Common species include:
                         itrus  fruits,  greenhouse

                             otton,   greenhouse
citrus  mealybug
Mexican   mealybug
red scales—citrus fruits, other tree  fruits,
San Jose scale—tree fruits,
brown  soft scale—tree fruits, ornamentals,
black scale—citrus.
   Whiteflies  are  tiny, soft-bodied  insects covered
with white, waxy powder. The adults have two pairs
of broad wings and resemble tiny white moths. Dur-
ing the  life cycle  they change  gradually in size and
form  from egg through  several wingless,  scalelike
nymphal stages and  a pupalike stage  to  winged
adults. Several generations are produced each year.
   Both nymphs and adults have long, slender tube-
like mouthparts and feed on plants by sucking plant
juices. They also secrete honeydew. Whiteflies attack
greenhouse crops in the North and a wide variety of
outdoor agricultural crops in the South.
   Common species include:
     » citrus whitefly,
     • greenhouse whitefly.
Moths  and  Butterflies
  Moth and butterfly adults have  a dense covering
of tiny scales and hairs on their wings and bodies
which gives the body a soft, fuzzy  appearance. The
adults have two  pairs of fairly large  wings  which
are usually brightly colored in butterfly species and
dull, neutral-colored in moth species.
  During  their life cycle they change  completely in
size and form from egg to wingless wormlike larva
to immobile  pupa to winged adult. One to  several
generations  are produced each year.  Adults have
long  tubelike mouthparts and feed on plants  by
sucking or siphoning plant nectar. They do not harm
plants; however, their presence around crops or in
pheromone or light traps may indicate potential pest
problems.  The adults lay eggs that hatch into poten-
tially  harmful larvae.

          Four  Stage  Life Cycle
                                                     The  larvae, called caterpillars, are long,  fleshy,
                                                   and soft-bodied with three or more pairs of  legs.
                                                   They have well-developed, toothed jaws and feed on
                                                   plants by cutting and tearing leaves, stems, and other
                                                   plant parts. Different kinds of caterpillars feed on
                                                   all parts of herbaceous and woody plants including
                                                   roots, stems, foliage, buds, flowers, fruits, and seed.
                                                   Injury to plants is characterized by  tears, tunnels,
                                                   and ragged holes in the affected plant part.


                                                     Budworms are medium-sized caterpillars that feed
                                                   in or on opening buds. Common species include:
                                                       • pecan budworm,
                                                       • tobacco budworm—tobacco, cotton.

Several  other destructive caterpillars, such  as  the
corn earworm, fall armyworm, and European corn
borer, may feed on or in developing buds. Although
these are not true budworms,  the injury they cause
is often called "budworm injury."


   Armyworms occur in large numbers, and may des-
troy every plant in their path. They will eat any part
of a herbaceous plant, especially stems,  leaves, and
fruits. Common species are the  fall armyworm and
true armyworm,  both  of which  attack grasses and
cereal grains.
       ARMYWORM:   (1)  EGG MASS;
       (4) LARVA; (6) ADULT

  Cutworms usually  feed near the soil surface by
cutting  through  succulent stems of young  plants.
Some cutworms can climb up stems and trunks to
feed on buds, leaves, and fruit and are called climb-
ing  cutworms. Different species of cutworms  may
attack many kinds of agricultural crops. Black cut-
worm is a common  surface-feeding caterpillar on
many vegetables and grain  crops. Variegated  cut-
worm will feed on the  soil surface and also act as
a  climbing  cutworm  attacking herbaceous  and
woody tissues.on fruits and vegetables.
   Borers are caterpillars  which bore  into and feed
on stems, woody tissues, and roots. Some other insect
larvae are also borers. They may attack young fruit
and nut trees and row crops. Common species in-
    • common stalk borer—corn,  potato, tomato,
       other stem plants,
    • European corn borer—corn, beans, peppers,
    • peach tree borer—stone fruits,
    • potato tuberworm—Irish potatoes,
    • citrus borer.
      (LEFT);  PUPA (TOP  RIGHT);

  Fruitworms  and some other caterpillars bore into
and feed on the fruits of plants. The caterpillar of
one moth species may be called the  corn earworm,
tomato fruitworm, or cotton bollworm, depending on
where it  is  feeding. These caterpillars also  bore in
and feed  on beans, cabbage, peanuts,  grasses, grains,
and other crop plants. Other common  species in-
       oriental fruit moth—tree fruits,
       codling moth—tree fruits,
       green fruitworm—tree fruits,
       tomato pinworm—tomato, potato.

   Foliage Feeders
  Foliage feeders are by far the largest group of cat-
erpillars. They may feed on the leaves of every type
of agricultural crop.

   Webworms and Tent Caterpillars are caterpillars
that build a nest or "tent" of silk. Webworms feed
entirely within the web, which is built around the foli-
age and is extended as the enclosed leaves are con-
sumed. Tent caterpillars build tentlike nests in the
crotch of a  tree and leave the nest to feed on the
foliage. Common species include:
     • eastern tent caterpillar—apples,
     • fall webworm—tree fruits, nuts,
     • garden webworm—grass, cereal grains, vege-
  Hornworms are very  large, foliage-feeding cater-
pillars with a hornlike projection at the end of the
body. Two comjnon species are tobacco and tomato
homworms, both of which attack tobacco, tomatoes,
potatoes, and peppers.
  Loopers, Cankerworms, and Spanworms are foli-
age-feeding caterpillars which move by drawing the
abdomen to thorax to form a loop and then extend-
ing again. They often drop down and dangle on a
long silken thread when disturbed. Common species
     • fall  and  spring  cankerworms—tree fruits,
     • cabbage looper—cole crops,  lettuce, other
     • currant spanworm—currants, gooseberries.
   Other Foliage-Feeding  Caterpillars include such
species as:
     •  redhumped caterpillar—fruits, nuts,
     •  imported cabbageworm—cole crops,
     •  parsley worm—many vegetables.
  In addition, there are several pest species  with
common names that describe how they attack and in-
jure leaves. For example:
    •  leaf crumplers crumple new leaves together
       with a silken thread and feed on new leaves
       and buds of some fruit crops,
    •  leaffolders feed  inside folded leaves of some
       small fruit crops,
    •  leafminers mine in and feed between the sur-
       faces of leaves of many fruit and vegetable

       leafrollers feed within the  rolled up  leaves
       of many fruit  and vegetable crops,
       leaj skeletonizers skeletonize leaves of some
       fruits, vegetables, and specialty crops by eat-
       ing everything but the veins and outer  layer.
       leaftiers tie together and feed on the  leaves
       of some small fruit crops.
   Beetles are the largest group of insects. They make
 up about 40 percent of known insect species. Adults
 are easily identified by the pair of hardened, opaque
 wings that meet in a straight  line down the thorax
 and abdomen and the folded  second pair of trans-
 parent wings.
   During their life cycle, beetles change completely
 in size and form from egg to wingless, wormlike larva
 to immobile pupa to winged adult. One generation
 may be produced every 2 to 5 years or several gen-
 erations may be produced each year. Both the larvae,
 some of which are called grubs, and the adults have
 distinct, hard, capsulelike  heads with toothed jaws.

 They feed on plants by biting and tearing the food.
 Many adult beetles feed on plant foliage or fleshy
 stems.  Larvae may  feed  on roots, stems, foliage,
 buds,  seeds, fruits, or woody tissue. Injury to the
 plant is characterized by tears and ragged holes in
 the affected plant part. In some species both the adult
 and the larva are pests. In other  species only one
 stage causes damage.
                  MA* JUNE JULY  AUG.  SEPT.  OCT.  NOV. DEC.
                     BEETLIS FEEC On FOLIM* ANC FRUIT

    Rootfeeding  Larvae

    These include wireworms, rootworms, and other
 beetles. The root-eating larvae feed on and burrow
 in roots and underground  stems. Wireworms also at-
 tack seeds.

    Wireworms are shiny, slender, hard-bodied, wire-
 like, yellow to dark brown larvae. They may be
 found at all times of the year in almost any soil.  The
 adults, which are not important pests, are called click
 beetles because they  right themselves with a sharp
 click if held or disturbed. Many species are pests.
 They may attack all agricultural  crops, especially
 corn, grasses,  tobacco, cotton,  and root vegetable
  Rootworms are small, curved, white, soft-bodied,
wormlike grubs.  The adult  beetles  are leaf-feeders
and may attack the foliage of entirely different plant
species than the crops injured by the grubs. For ex-
ample, the clover rootworm, which feeds on pasture,
hay,  and grain  crops, becomes  the grape  colapsis
beetle, which feeds  on  small fruit and vegetable
crops. The southern corn  rootworm, which feeds on
corn   and  beans,  becomes  the  spotted  cucumber
beetle, which feeds on legumes and cucurbits. Other
common species include:
    • northern corn rootworm,
    • strawberry  rootworm—small   fruits,   tree
       fruits, nuts.

  Other beetles with root-feeding larvae also include
species in which the adults feed  on different hosts
than the grubs do. Japanese beetle adults feed on all
fruits and on corn and soybean foliage, but the grubs
feed on grass roots. May and June beetle adults feed
on foliage of ornamental trees  and shrubs, but the
grubs feed on roots of hay, pasture, grain, and vege-
table crops. The striped cucumber beetle adults feed
on foliage of cucurbits, legumes,  and corn, but the
larvae feed only on cucurbit roots.

   Stem-Eating Larvae or Borers
  Stem-eating larvae tunnel in and  feed on stems
and woody tissues.  The adult  beetles  often  cause

 damage by carving holes in stems and bark to insert
 eggs, as well as by eating foliage. Borers are partic-
 ularly destructive to newly set or weakened fruit and
 nut trees  and young herbaceous  crops.  Common
 species are:
     • potato stalk borer—potatoes, tomatoes,
     • cane borers—small fruits,
     • shot hole borer—fruits, nuts,
     • round headed and flat headed borers—tree
        fruits, nuts.

    Fruit- and Foliage-Eating Larvae
   This group  includes  snout  beetles  and  other
beetles. In many species  of beetles, both larvae and
adults feed on foliage and fruit.
   Snout Beetles (Curculios, Bilibugs, and Weevils)—
The head of the adult snout  beetle is shaped  in a
long, curved snout  with  toothed mouthparts at the
tip. The larvae are  white, thick, soft-bodied,  legless
grubs. The grubs commonly feed within the plant;
the adults feed from the outside. The snout  of the
adult beetle is used to cut a hole in stems, nuts, buds,
fruits,  or vegetables into  which the eggs are depos-
ited. The hatching grubs eat and bore their  way fur-
ther into or along the stem or fruit.
   Snout beetles  which feed on hay, pasture, grain,
and soybean crops are commonly called  billbugs.
Common species are:
     • southern  corn billbug—corn, rice,  peanuts,
     • maize billbug.
    Snout beetles which feed on fruits and nuts may
 be called curculios. Common species include:
      • apple curculios—tree fruits,
      • plum curculios—stone fruits, apples.
    Snout beetles which attack vegetables and specialty
 and ornamental crops are often called weevils. Com-
 mon species are:
      • alfalfa weevil,
      • cotton boll weevil,
      * bean weevil—bean seeds,
      * pea weevil—pea seeds.
                            ALFALFA WEEVIL
  Other Fruit- and Foliage-Feeding Larvae are not
snout beetles. The larvae of these beetles usually feed
on  the  outside of the plant along with  the  adult
beetles.  The adults usually deposit the eggs on the
leaf or stem surface rather than into the plant. Com-
mon species include:
     • flea beetles—vegetables,
     • Colorado potato beetle—potatoes, tomatoes,
     • Mexican bean beetle.
                       FLEA BEETLE
    Non-Plant-Eating  Larvae
   The larvae of some pest beetles do not eat plants
but prey on insects, mites, and other animals. The
adults are called blister beetles because they contain
a chemical which may blister human skin. The adult
blister beetles chew on foliage and fruits and may be
very destructive to agricultural crops. The larvae of
blister beetles  are  parasitic  on  grasshopper  eggs.
Numerous species feed on vegetables, flowers, young
trees, and vines.

 Flies,  Gnats, and  Midges
   Flies,  gnats, and midges are  the major types  of
insects with only one pair of wings. During their life
cycle they change  completely from egg  to wingless,
wormlike larva  to immobile pupa to  winged adult.
The pupal stage of most  pest flies is buried in the
soil and  adults emerge from the soil to feed. Several
generations are produced each year.

   Adults have piercing-sucking or sponging mouth-
parts. Many adults feed upon nectar  and pollen of
flowers. Others feed upon liquid organic matter from
decomposing plant or animal bodies. Others dissolve
solid  substances in their saliva and sponge up the
solution.  A number of adults suck  juices from other
insects and animals, including man.
   Sawflies belong to the  group of insects that in-
cludes bees, wasps, and ants. Sawfly larvae resemble
caterpillars. The adults have two pair of transparent
wings hooked together. During their life cycle  they
change  completely from  egg to wingless wormlike
larva to immobile pupa to winged adult. One  to a
few generations are produced each year.
   Larvae  and adults have toothed jaws and feed on
plants by  tearing  soft stems and foliage. The  adults
damage plants mainly by  sawing into leaves  to de-
posit eggs. The larvae are the most destructive stage.
They bore into and feed on stems and leaves, often
by burrowing between the surfaces of a leaf as leaf-
miners do.
  Injury to plants is  characterized by slits in leaves;
lumpy, wilted foliage; and stunted growth.
  Common  species include:
     •  stem sawflies—grasses,  cereal grains,
     • cherry fruit sawfly—tree fruits,
     •  imported  currantworm—currants, gooseber-
                 HESSIAN FLY
   The larvae, called maggots, are usually soft, thick,
white, and legless with a head which is not well de-
fined. Maggots have well-developed, parallel hooked
jaws. They feed on plants by burrowing in  and feed-
ing on roots, stems, and fruit. The maggots are us-
ually the most destructive stage.
   Injury to plants is characterized by wormy or de-
cayed seeds, stems,  fruits, and roots; wilted foliage;
stunted growth; or death of the plant. These insects
may also transmit some plant disease agents, espe-
cially those causing soft rot.

   Common species include:
     • apple, cabbage, pepper, and onion  maggots,
     • seed corn maggot—vegetable  seeds,
     • melon fly—cucurbits,
     • Hessian fly—wheat,
     • sorghum midge—grasses, cereal grains,
     • fruit flies.

   Mites are minute, soft-bodied, wingless pests which
 closely resemble insects but have eight legs. Nymphs
 and adults  have  sucking mouthparts. They usually
 are so tiny  that they are  discovered only after  the
 damage to the plant appears. The life cycle includes
 both  larval  and  nymphal  stages.  The  larvae have
 three pairs of legs; the nymphs  and adults have four
 pairs. Several generations  are produced each year.
   Foliage, buds,  stems, and  fruit of infested plants
 may become red, bronze, rust,  yellow, white,  or
 brown or may wither and fall off.  Spider mites spin
 light, delicate webs  over buds  and between leaves
 where mites are feeding. Mites attack almost al! types
 of agricultural crops.
   Common species include:
     •  spider mites—fruit trees, citrus,  small fruits,
       legumes, greenhouse crops,

     • clover mite—grasses, cereal grains,
     • red mites—tree fruits, citrus, nuts.
Plant  Disease  Agents

  Both living organisms and  nonliving agents often
cause diseases or other undesirable effects on plants.
     • Living organisms include fungi, bacteria, vir-
       uses and mycoplasmas, nematodes, and para-
       sitic seed plants.
     • Nonliving agents include unbalanced soil fer-
       tility,  toxic  chemicals, air pollution, frost,
       drought, sunburn, wind, and hail.

Disorders caused by nonliving agents often resemble
the symptoms of injury caused  by living organisms.
For  example, certain  types of chemical injury can
look like some of  the leafspots caused by fungi or

  Symptoms and signs are  the keys to identifying
plant disease. A symptom of a disease is the reaction
of the host  plant to the living organism or to the
nonliving agent. Symptoms include  such things as
spots on  the leaves, wilting,  and galls on the roots.
A sign is physical evidence of the presence of a dis-
ease agent. Signs include, for example, the visible
growth of fungi (mold) or fungal spores, or bacterial
ooze issuing from a wound.

  Some  living organisms cause   entirely  different
symptoms on different kinds  of plants. Cedar  apple
rust on cedar appears as gall-like  swellings on twigs,
but on apple it appears as small,  rustlike spots. Dis-
eases  caused  by nematodes may have no visible
above-ground symptoms if soil moisture is adequate.
Root knot nematode injury on peanuts is an example.
A plant  may be infected by two or more disease
agents at the same  time.

  Fungi are plants that lack chlorophyll and cannot
make their own food. They get food by living on
other organisms. Most fungi reproduce by  spores,
which function about the same way seeds do. Locat-
ing and recognizing the spores may be a key to iden-
tifying a fungus as the cause of a plant disease. Fungi
may  attack  crops  both  above and below  the  soil
surface. Fungal disease agents may be  spread from
plant to plant and crop to crop by such things as
wind, rain, insects, birds, machinery, soil, and con-
laminated seed  stock.
   Leaf  Diseases

  Although the fungi causing these diseases occur
primarily  on leaves, some may also occur on stems,
roots, or  fruits. Fungi that cause leaf diseases pro-
duce several types of symptoms. Other plant disease
agents may produce similar symptoms.

  Leaf  Spots—Leaf spots (other  names—anthrac-
nose,  scab,  leaf blotch,  shot hole)  are usually def-
inite spots of varying sizes, shapes, and colors. Each
spot usually has  a distinct margin, sometimes sur-
rounded by a yellow halo. Usually there  is  a fungal
growth such as tiny, black, pimplelike structures or a
moldy growth.  It is  often necessary to use a hand
lens to see these signs. If the spots are numerous or
close  together,  affected  areas may join together to
form  irregular  areas,
often called "blotches".
Leaf spots are  common on
fruits, vegetables, and some
hay and pasture crops.

   The common names of leaf spot diseases may be
general (peanut leaf spot), descriptive  (zonate  leaf
spot), or  named after  the fungus  (Septoria  leaf

   Leal Blights—Leaf blights look somewhat like  leaf
spots but generally cause larger and more irregularly
shaped diseased areas. Blights are common  on al-
most all food and  feed  crops. The common name
usually includes  the  word  "blight" (southern  leaf
blight, early blight).

   Rusts—Rust  fungi often  produce  "pustules,"
which look like leaf spots.  Rust pustules are  masses
of bright yellow, orange-red, reddish brown, or black
spores being  pushed through the  leaf surface. With
severe infections, the leaf withers and dies rapidly.
Some types of rust also occur on stems.
   Rusts are most common on grains, pasture grasses,
and  tree  fruit crops. The common name usually in-
cludes the  name of the crop affected and the word
"rust" (stem rust of grains and grasses, leaf and cane
rust of raspberry).

   Powdery Mildew—Powdery mildew is a white to
light gray,  powdery or dusty  growth on leaves. It
may also occur on stems, fruits, and flowers. Affected
leaves usually turn yellow, wither, and die.  Powdery
mildew is common  on curcurbits, small grains, and

  Downy Mildew—Downy  mildew is a light gray,
moldy growth on the underside of the leaf. It  causes
a pale green  to yellow area on the upper leaf sur-
face. Downy  mildew fungi are important disease
agents on some vegetables such as pepper, cabbage
and soybeans.
 Symptoms of Diseases
'" Powdery
•  Mildew
    Wilts, Root Rots,  and Crown  Rots
   These  three  distinct  groups  of  fungal  disease
 agents are usually soilborne. The fungi  can  survive
 for long periods  of time in the soil. These organisms
 produce similar general symptoms (wilting and death
 of the plant). Close examination of  a wilting plant
 will nearly always allow you to determine  if it  is
 caused by wilt, root rot, or a crown rot.

   Wilts—Most wilt  diseases are  caused  by fungi
 (Fusarium and Verticillium), although bacteria may
 produce  similar  symptoms.  These parasites cause
 wilts on a wide range of crops. Wilt disease agents
 usually enter the plant through the roots. Some of
 the roots may be black and rot in the early stages of
 the  disease.  Extensive  root rotting does not occur
 until after the plant is dead. A light-  to dark-brown
 streaking can usually be seen in  the  stem of an in-
 fected plant.
   Crown Rots—These disease agents usually attack
 the plant at or near the soil line. Affected plants are
 generally unthrifty  with  leaves  smaller  or  lighter
 green than normal.  Leaves usually turn yellow.  In
 advanced stages of disease, the plant  wilts and dies.
 The crown or base of the  stem will be water-soaked,
 discolored, or decayed. A moldy growth with var-
 ious colored fruiting bodies often forms in the dis-
 eased area. Crown rot can be important on some
 vegetable crops.  Common names may include  the
 words crown rot, collar rot, stem blight, stalk rot,
 or southern blight.
   Root Rots—Some plants may wilt and die rapidly;
 others may be slow-growing, yellow, or stunted and
 may not die  for some time after  the  symptoms ap-
 pear. Roots are generally shortened,  soft, and light
 brown to black. The outer portion  of the root may
 slough off, leaving a stringlike center core.  Every
 type of agricultural  crop may be affected by root

   Stem Cankers
   Stem cankers  occur as well-defined,  discolored
 areas on main stems or branches. These areas may
 be irregular or oval; they may be sunken or swollen.
 Some cankers crack  open and expose the wood un-
derneath.  The foliage on  stems with  cankers is us-
 ually  slow-growing,  light  green to  yellow, and  re-
duced in size. Infected stems often start growth later
in the  spring. The tips of infected stems may die
back. Infected branches and plants  may not die for

 several months or even years after the disease first
 develops. Stem cankers are  very important on tree
 fruit and nut crops.

    Fruit Rots

   Fruit rots are caused by many different kinds of
 fungi. All types of fruit are susceptible to rots. The
 symptoms vary from a superficial fungal  growth on
 the external surface to a mushy, soft, watery rot. Rot
 may  occur while the fruit is on the plant or  after
 harvest. Some rots  begin as a small spot sunken be-
 low  the surface, containing spores  or other fruiting
 bodies of the fungi. Some rots may cause a shriveling
 or a  "dry  rotting" of  the fruit. Many rot-causing
 fungi occur only on one type of fruit; others  may
 occur on different  fruits.
    Seed  and Seedling Diseases

   Seedling diseases are caused by soilborne fungi.
 They usually occur during the period from germina-
 tion until  shortly  after emergence. If infection oc-
 curs  before emergence,  the  seedling  may  never
 emerge.  After emergence,  seedling stems  may  be
 attacked at or slightly below the soil line.
   Symptoms  include  brown  to reddish-brown  or
 black cankers at the soil line which may girdle the
 stem. A second type of symptom is a soft, watery,
 rotted spot at the soil line. Seedling and seed diseases
 are most common  in cool, wet soils. Any  agricultural
 crop grown from seeds or seedlings may  be affected.
 Among the common names for these fungal diseases
 are damping-off and seed rot.

   Bacteria are  microscopic, one-celled  organisms.
They usually reproduce by dividing in half. Bacterial
numbers can build up fast under  ideal conditions
such  as warm,  humid weather. Bacterial disease
agenls can be identified by the symptoms they pro-
duce in plants or by signs of the bacteria's presence.
Bacteria may attack any part of a plant both above
and below the soil  surface. Bacterial  disease agents
are spread from plant  to plant  and  crop to crop by
infected  seed, man, insects, and other animal life
including birds, snails, slugs, and worms, and by con-
taminated rain,  irrigation water, equipment, tools,
    Bacterial  Wilts

   Bacteria which attack the water-conducting vessels
 of plants generally  cause  the same  plant  disease
 symptom—wilting.  The  water-conducting  tissues
 may become so filled with bacteria that water can
 no longer be supplied to the  foliage  and the  plant
 wilts. Often if the stems of infected plants are cut, a
 whitish bacterial ooze may form at the ends of the
 water-conducting vessels. Often the stem of the in-
 vaded plant is stained brown or black. Bacterial wilt
 may affect many types of agricultural  plants,  espe-
 cially cucumbers, tomatoes, and cabbage.
                           AND TO OTHER VINES
   Bacterial Blights,  Leaf Spots, and Rots
   Bacteria may attack the soft or succulent plant tis-
sues and cause death of the affected areas. On leaves
the symptoms are very similar to leaf spot and blights
caused by fungal agents. Typically, the first symptom
on the leaves appears as water-soaked spots, which
finally turn to brown or "dead" areas. The rot  of
many fleshy  roots, stems, rhizomes, and fruits is a

 rapid, soft, wet, bacterial rot.
 •  Bacterial blights, leaf spots, and rots may be dis-
 tinguished from similar fungal diseases by presence
 or absence of spores  (indicating fungus), or by the
 host which is affected. Often a microscopic examina-
 tion is needed. Common diseases in this category in-
 clude fire blight of apple and pear, angular leaf spot
 on cucurbits and  tobacco, and soft rot of vegetables
 such  as potatoes  and  onion.

   Bacterial  Galls and  Overgrowth

   Bacteria may cause abnormal  cell division in  a
 portion of a plant, causing tumors, galls, or witches-
 brooms. Often the symptoms are easily seen with the
 naked eye. These diseases may attack a wide variety
 of agricultural crops and are especially important on
 tree  fruits and nut crops. Two  common diseases in
 this group are crown gall and hairy root of apple.

 Viruses  and Mycoplasmas

   Viruses and mycoplasmas are so small that they
 cannot be seen with an ordinary  microscope. They
 are generally recognized by their effects on plants.
   Viruses depend on other living organisms for food
 and to reproduce. They  cannot complete their life
 cycle  independently. They are transmitted by insects
 (usually aphids or leaf hoppers), by infected  plants,
 pollen, fungi, nematodes, or contaminated machinery
 and men.
   Mycoplasmas are the smallest  known  independ-
 ently  living organisms. They can reproduce and exist
 apart  from other living organisms. They obtain their
 food from plants.  Most known mycoplasma diseases
 are transmitted by leafhoppers. Yellows diseases and
 some  stunts are caused by mycoplasmas. Often it is
difficult  to distinguish between  diseases caused by
 viruses and mycoplasmas and those caused by other
plant  disease agents.
  Common symptoms of both virus-caused and my-
coplasma-caused diseases include:
    • mosaic—light  green to yellow areas  of the
      leaf,  usually accompanied  by abnormal leaf
    • vein banding—a  light green  to yellow band
      along leaf  veins, which may later turn  dark.
    • ring spot—alternating rings of light green or
      yellow and normal green of  the leaf.
    * yellows—the entire plant or  some parts are
      uniformly yellow.
     • stunting—some or all parts of the plant are
       abnormally  small.  Stunting may  occur  in
       combination with all of the previous symp-
     • rugose—leaves are crinkled and deformed.
   Every type of agricultural crop may be affected by
virus and  mycoplasma diseases.


   Nematodes are small, usually microscopic, round-
worms.  All  nematodes that are parasitic on plants
have a hollow feeding spear (stylet). They use it to
puncture plant cells and feed  on the  cell contents.
Their life  cycle includes an egg, four larval stages,
and  an adult. In adverse conditions, some nematodes
can  assume  an inactive form called  a  cyst which is
difficult to penetrate or kill.
   Nematodes may feed on plant roots, stems, leaves,
and  flowers. The most damaging root-feeding nema-
todes directly interfere with water and nutrient up-
take. Nematode damage often goes unrecognized or
is  blamed  on something else. Typical above-ground
symptoms include stunting, yellowing,  loss of vigor,
and  general  decline.
   Nematode injury in the field is  rarely uniform.
Damage often occurs in scattered areas of a field.
Symptoms of injury become more obvious when soil
moisture and fertility are low. Injury to the plant by
nematodes may appear as galls, knots, stubby roots,
and damage  to or loss of feeder roots. Nematode in-
festations  may  be determined  by having  the  still-
living plant  roots  and surrounding soil examined in
a diagnostic laboratory.  There are  many different
species of nematodes which attack every type of ag-
ricultural crop.
           Nematode Damage
 Actual Lengft Equals V50 to V25 Inch

 Parasitic  Seed  Plants

   Dodders, broomrape, and witchweed are parasitic
 seed plants which are important disease agents on
 agricultural crops.
   Dodders  are  leafless, orange  to  yellow  twining
 vines. They do not have chlorophyll and must obtain
 their food  from other living  plants.  Dodder germi-
 nates in the soil  and produces a slender, yellowish
 thread.  When it touches the host, it twines around its
 stem  and puts out  little  suckers. As  soon  as the
 suckers are established on the host plant, the roots
 of the dodder shrivel and the connection to the soil
 dries  up.  Successful  dodder parasites twine  and
 spread from one plant to the next. They often appear
 as a tangle of matted orange hairs. Dodders  parasit-
 ize clover,  alfalfa, and flax and are becoming more
 important on some vegetables.
   Broomrape is a leafless herb which appears above
ground  as a clump of  whitish, yellowish, brownish,
or purplish stems. It germinates from seed in the soil
 and produces a slender stem. The slender stem grows
downward into the ground and penetrates the crown
 or root  of the  host plant. Upon contacting the host,
 the bfoomrape forms  a  tuberous enlargement and
 draws its food from  the host. The flowering shoots
 appear above ground and  a new generation of seeds
are formed. Broomrape attacks  tomatoes,  lettuce,
 and other vegetables  and may live on weeds between
 crop plantings.
   Witchweed,   as  it  appears above ground,  has
bright-green fuzzy  stems and leaves  and  small,
brightly colored flowers in red, yellow, or white. It
germinates from  seed  only when  a  favorable host
plant is  present. The  witchweed rootlet grows down-
ward to the root of the host plant, penetrates the host
root and feeds on the juices,  plant foods,  and min-
erals from the  host. The flowers are produced above
ground. Seeds mature  and lie dormant in the soil
until chemicals given  off by a suitable host  plant
stimulate  germination.  Witchweed attacks  grasses
and sedges  including corn,  sorghum,  wheat, oats,
and barley.

Snails  and  Slugs

   Upland snails and slugs are members of  a large
group of animals including oysters, clams, and other
shellfish called mollusks. All mollusks have soft, un-
segmented bodies and are often protected by a hard
shell.  Snails and  slugs have  two pair  of  antennae
or feelers. Their bodies are smooth and elongate with
a slimelike mucous coating.
   Snails  have  a spiral-shaped shell into which they
can completely withdraw  when disturbed or when
weather conditions are unfavorable. They are usually
grey, but their shells vary from nearly white through
brown to black and are often decorated with stripes
or spots of contrasting colors.
   Slugs do not have a true shell and must seek pro-
 tection in damp places during daylight hours.  Like
 snails, they emerge at night to feed. They range in
 length from V* inch to 8 to 10 inches, and may be
 whitish-yellow to black, usually with mottled spots
 or stripes.
   Snails and slugs feed on plants by tearing holes in
 foliage, fruits, and soft stems, using a rasplike tongue.
 They may eat entire seedlings. Injury to  plants is
 characterized  by jagged holes  in foliage, stems, and
 fruit. Snails and slugs also leave a trail of mucus on
 the surfaces which  dries into  silvery streaks. These
 silvery streaks may be undesirable on floral and or-
 namental crops and on those portions of crops to be
 sold for human food.
   Snails and slugs deposit eggs in moist, dark places.
 The young mature in a year or more, depending on
 the species. Adults  may live for several years. They
 overwinter in  sheltered areas in colder regions of the
 United States. They are active year-round in warm
 regions and in greenhouses. They may attack many
 different  agricultural  crops.  Common  species in-
        spotted garden  slug (8 inches),
        tawny garden slug (4 inches),
        grey or true garden slug (1 inch),
        brown garden snail,
        banded wood snail,
        white  garden snail,
        subulina snail.


   Knowledge of the characteristics and life cycles of
 the weed species and the agricultural crops to be

protected is necessary for a successful weed control
program. Weeds harm desirable plants by:
     • competing for  water,  nutrients, light,  and
     • contaminating the product at harvest,
     • harboring pest insects, mites, vertebrates, or
       plant disease agents, or
     • releasing toxins in the soil which inhibit crop

Development  Stages

  All plants have four stages of development:
     • seedling—small, vulnerable plantlets;
     • vegetative—rapid growth and production of
       stems, roots, and foliage. Uptake and move-
       ment of water and nutrients  is rapid  and
     • seed  production—energy  directed  toward
       production of seed. Uptake and movement of
       water and nutrients slow and directed mainly
       to flower, fruit, and seed structures;
     • maturity—little or no energy  production or
       movement of water and nutrients in plant.
  Annual plants complete all four stages of growth
in one year. Common annual weeds include: foxtail,
pigweed, lambsquarters,  cheat, henbit, and cockle-
                               MATURITY (ANNUALS)

   Biennial plants complete the seedling and vegeta-
 tive stages of growth in the first year and the seed
 production and maturity stages in  the  second year.
 Common biennial weeds include: mullein, burdock.
 bull thistle, and wild carrot.
                FLOWERING  (PERENNIALS)
               MATURITY (PERENNIALS)
  Perennial plants may complete all four  stages in
the first year  and then repeat the  vegetative,  seed
production, and maturity stages for several following
years. Or the  seed production and  maturity stages
may be delayed  for several  years. Some  perennial
plants die back  in the maturity stage each  winter;
others, such as trees, may lose their leaves  but  do
not die back to the  ground. Common  perennial
weeds include: Johnson grass, field  bindweed, wild
garlic, dandelion, and sumac.

         Annuals, Biennials, and Perennials
 Weed  Classification

   Most pest plants are either grasses or broadleaves.
 The sedges, such as the nutsedges, are not classified
 as either grasses or broadleaves. However, they have
 similar characteristics to grasses and are often listed
 under grasses on the pesticide label. Grasses, sedges,

 and broadleaves contain species with annual, bien-
 nial, and perennial life cycles.


   Grass seedlings have only one leaf as they emerge
from the seed. Their leaves are generally narrow and
upright with parallel veins.  Most grasses have fibrous
root systems. The growing  point on seedling grasses
is  sheathed and located below the soil surface. Ex-
amples of grass weed  species are: foxtail,  Johnson

           Grasses and Broadleaf Plants
tact herbicide sprays.

   Broadleaf  seedlings  have  two  leaves  as  they
emerge from the seed.  Their  leaves are generally
broad with netted veins.  Broadleaves usually have a
taproot and a relatively  coarse root system. All ac-
tively growing broadleaf plants have exposed grow-
ing points at the end of  each stem and in each leaf
axil. Perennial broadleaf plants may also have grow-
ing points on roots and  stems below the surface of
the soil. Examples of broadleaf weed species include:
pigweed, mullein, dandelion, plantain, sumac, poison

Factors  Affecting  Control

   In planning a weed control program,  differences
between  weeds  and the  crop species,  such as life
cycles, foliar characteristics,  and herbicide suscep-
tibility must be  exploited. Generally the more simi-
lar the crop and weed species are to one another, the
more difficult weed control becomes. Plants differ
in susceptibility due to:

   Growing Points—Those that are sheathed  or lo-
cated below the soil surface are not reached by con-
          ,:W     4
             T   ID
                                                           SEEDLING   ANNUAL
  Leaf Shape—Herbicides tend to bounce or run off
narrow upright leaves. Broad, flat leaves tend to hold
the herbicide longer.

  Wax and Cuticle—Foliar sprays may be prevented
from entering the leaf  by a thick wax  and cuticle
layer. The waxy surface also tends to cause a spray
solution to form droplets  and run off the leaves.
  Dense  Layer of Leaf Hairs—This holds the her-
bicide droplets away from the leaf surface.

  Thin Layer of Leaf Hairs—This causes the chemi-
cal to stay on the leaf surface longer than normal.

  Size and Age—Young, rapidly growing plants are
more susceptible to herbicides than larger, more ma-
ture plants.

   Deactivation—Certain plants can deactivate herbi-
cides and are less susceptible to injury from these
chemicals. Such plants may dominate over a period
of time if similar herbicides are used repeatedly.
   Stage in Life Cycle—Seedlings are very susceptible
to herbicides and to most other weed control prac-
tices. Plants in the vegetative and early bud stages
are  very susceptible  to  translocated  herbicides.
Plants with  seeds  or  in  the maturity stage are  the
least susceptible to weed control practices.
   Timing of Stages in the Life Cycle—Plants that
germinate and  develop at different times  than  the
crop species may be  susceptible to carefully timed
herbicide applications.

Determining  the  Weed  Problem

   In cultivated crops, the weeds that are favored by
crop production practices do best. The crop produc-
tion method, especially the use or nonuse of cultiva-
                                                         tion, is often more important in determining the size
                                                         and kind of weed problem than is  the crop species
                                                            Weeds with physical characteristics; growth habits;
                                                         soil, water, nutrient, and light requirements; and  life
                                                         cycles that closely resemble crop habits and require-
                                                         ments are usually the most  serious competitors  to
                                                         crop species. Broadleaf weeds are often difficult to
                                                         control  in broadleaved  crops, and  grass weeds  are
                                                         often difficult to control in grass crops, because of the
                                                         close physical resemblance and growth requirements.
                                                         There are exceptions, however. Broadleaf weeds may
                                                         be serious in grass crops and vice versa.
 Weed Control  Methods

   Choose the weed control method which takes into
 account the differences between the crop and weed
 species. Be sure that the crop you are trying to pro-
 tect  is not susceptible to  the weed control  method
 that you choose. Read the herbicide label.
   Cultivation—This is  a  traditional and often-used
 method to kill or control weeds in row crops. How-
 ever, cultivation may bring buried seeds to the sur-
 face where they can  either germinate and compete
 with the newly-planted crop or be spread to  nearby
 fields. Cultivation may also increase soil erosion and
 may help to spread established  plant diseases to un-
 infected areas of the field.
   Planting Timing—Fall-planted crops compete well
 against  summer  annual  weeds.  Spring-planted crops
 compete well against winter annual  weeds.  Some-
 times the  crop planting date can be delayed until
 after weeds  have sprouted and have been removed
 by cultivation or by herbicides.

   Nurse Crops—Plant species  (usually annuals)
 which germinate quickly and grow rapidly are some-
times planted with a perennial crop  to compete with
weeds and  allow the  major crop to become estab-
lished. The nurse crop is then removed or harvested
to allow the  perennial  crop to take over. For ex-
ample, oats are  sometimes used as  a  nurse crop to
 aid in establishing a crop of alfalfa or  red clover.

   Fire—Fire may be used to control limited  infesta-
tions of annual or biennial weeds. Fire usually des-
troys  only the tops of  weeds  and  is not effective
against perennial weeds.
   Mulching—Mulching  is  used to prevent light from

 reaching  seedling  weeds,  thus  preventing  weed
 growth  between  crop rows or  around  trees and
   Mowing—Mowing  may be  used  to reduce com-
 petition and prevent flowering and seeding of annual
 or biennial weeds. Mowing is often used in orchards
 to control weeds and prevent soil erosion.

   Flooding—Flooding has long been used for weed
 control  in  certain crops such  as rice. The water
 covers the entire weed, killing it by suffocation.

 Vertebrate  Pests

   Vertebrate animals  may damage or destroy agri-
 cultural  crops and equipment either in the field or
 in storage. Some pests, such as birds, rodents,  rac-
 coons, deer, or coyotes, may damage crops or live-
 stock in  the  field.  Beavers may flood  low-lying
 cropland by building dams in creeks  flowing through
the area.  Birds and rodents  often contaminate and
ruin more food in storage than  they consume.
   Barriers, trapping, repellents,  and  pesticides  all
help to control  vertebrate pests.  Pesticides cannot
be used unless the specific pest can  be legally con-
trolled with pesticides under  State and  Federal laws.
Always check with local  authorities  before using
pesticides to control vertebrate  animals. Local  and
State laws may prohibit the killing of some vertebrate
animals such as birds,  coyotes,  and beavers.

             Vertebrate Pest Animals


   Insecticides are chemicals used to control insects.
Insecticides such as malathion or parathion kill the
insect by touching it (contact poison).  Insecticides
such as lead arsenate and Paris green have  to  be
swallowed to be effective (stomach poison).  Insec-
ticides called systemics, such as dimethoate or aldi-
carb,  are absorbed,  injected, or fed into the plant
to be protected. When the insect feeds  on a plant
protected by a systemic insecticide, it eats the chem-
ical and is killed. Some insecticides, such as demeton
or aldicarb,  have all three properties. They can kill
either by contact or if eaten, and they are systemic.
                Ways Pesticides
                  Attack Pests
   Contact Poison
                   Stomach Poison
                                    Systemic Poison
   Insecticides vary in the number of different kinds
of insects that  they kill. Some insecticides, such as
methoxychlor or carbaryl, are highly selective  and
kill only certain kinds of insects. Sometimes you can
choose insecticides that will kill only the pest insect
and not  harm  beneficial insects in the area.  Many
insecticides, such as parathion or pyrethrins, are non-
selective and kill  most kinds of insects. Every  in-
secticide is different.  One  that is highly  effective
against one pest may not be effective against another
   Insecticides also vary in how long they last as a
killing agent after they have  been  applied.  Some
chemicals,  such as chlordane, are persistent, remain-
ing active  for weeks  or months. These  insecticides
are often used when control over an extended period
of time is needed. Other insecticides, such as carbaryl
or pyrethrins,  are nonpersistent  and break  down
quickly (several hours to a few days) into byprod-
   Read each insecticide label carefully to determine
the insects  it will control and how to use it properly.
Always choose the safest insecticide for your situa-


   Miticides are chemicals used to control mites. Us-
ually  these are contact poisons  (such as acarol,

chlorobenzilate,  or Plictran)  or systemic poisons
(such as demeton). Thorough coverage is  usually
necessary to control the pests. A few, such as Acrex,
are stomach poisons. Miticides are similar in action
to insecticides. Often the same chemical, such as car-
bofuran or parathion, kills both insects  and mites. A
miticide  may  be selective, like Plictran or  chlor-
opropylate, or nonselective, like Acrex or chlordime-
form. A  miticide may also be persistent, like acarol
or chloropropylate, or nonpersistent like Acrex or

   Fungicides are chemicals used to control the fungi
which cause plant diseases. All fungicides are  con-
tact or systemic  poisons. Most fungicides, such  as
captan or maneb, must be applied to cover all plant
surfaces in order to  control fungus organisms.  Sys-
temic fungicides such as  benomyl move in the plant
to be protected.
   There are two approaches to the use of fungicides.
One is to prevent the plant from getting the disease.
Used this way, fungicides  are called protectants. They
are applied before the disease  gets a start. This  type
of fungicide, such as  zineb, thiram or Bordeaux mix-
ture, is the  most commonly used. Some fungicides
control  the fungi after they appear on  (or in) the
plant. This use of fungicides is called "eradication."
Eradicants  are  much less common than protectants.
Benomyl  may be   used  as  both  eradicant  and
protectant in some disease control programs.

  The word "fungicide" is often used to describe all
chemicals which are used  to control plant  disease
agents. The correct term for chemicals used  to con-
trol  bacteria-caused plant  diseases  is  bactericide.
Some chemicals, such as fixed copper,  help  to con-
trol both fungi and bacteria. Others, such as strep-
tomycin, are only effective against bacteria.
  Because bactericides are contact poisons, thorough
coverage is necessary to control all the bacteria. Bac-
tericides are similar in action to fungicides and are
applied either as protectants or eradicants. Some-
times the same chemical may be both a protectant
and an eradicant.
Controlling  Viruses  and


  No chemicals are  presently used to directly con-
trol viruses or mycoplasmas that cause plant diseases.
Control of these plant disease agents may be  accom-
plished by:
     • Using disease-free plants—"certified" means
       that plants have been inspected during the
       growing  season  and  found free  of  certain
     • Using plants or seeds  resistant to  specific
       virus or mycoplasma diseases.
     • Eliminating alternate plant  hosts.
     • Using cultural practices such as crop  rota-


   Nematicides are chemicals used to control nema-
 todes. Because most nematicides are contact  poisons,
 thorough application is necessary to protect the plant
 against nematodes in an area. Most of the early ne-
 maticides were soil fumigants. These must be applied
 before  planting because they  kill most  living  or-
 ganisms in the soil. More  recently, several  contact
 nematicides have been  developed.  They kill nema-
 todes without injury to newly seeded crops or peren-
 nial plants. Some of these contact nematicides  are
 also effective insecticides. Crop rotation and the use
 of nematode-resistant plant varieties can be effective
 methods of controlling nematodes.  Some common
 nematicides are carbofuran, aldicarb, Nemacur, and

 Controlling  Parasitic  Seed  Plants

  Parasitic seed plants may be controlled through the
use of herbicides. Dodders, broomrape, and witch-
weed all may be controlled with certain herbicides.
Special attention must be paid to the type of  crop to
be protected. The same herbicide  may not be used
with every crop host. Other means of control  include
avoiding seed  that is infested with parasitic plants
and controlling the plants before seed is set for the
next season.


  Pesticides used to control snails and  slugs are

called molluscicides. They are formulated as baits,
dusts, or sprays. Baits  should  be placed in areas
where birds and other  non-target animals  cannot
reach them. Dusts and  sprays are contact  poisons
and should be directed at the surfaces which snails
and slugs may crawl  over or feed upon. Common
molluscicides include metaldehyde, arsenic, and Bay-

  Both the use of a herbicide and the way it is ap-
plied depend upon these characteristics of the active
    • foliage-absorbed or root-absorbed,
    • contact or translocated,
    • selective or nonselective,
    * persistent or nonpersistent.

         Selective vs Nonselective Herbicide
                 ;:"*  SK*  .
         Selective               Nonselective

          Preemergence and Postemergence
                                     certain plants or plant parts. There is  little or  no
                                     translocation to underground or shaded parts of the
                                     weed. Grasses and perennial broadieaved weeds with
                                     below-ground growing points will recover after treat-
                                     ment. Seedling plants and annual and biennial broad-
                                     leaved weeds  can best be  controlled with these
                                     herbicides. Examples: dinoseb, paraquat, diquat.

                                       These herbicides kill certain kinds of plants when
                                     they contact the foliage. Differences in foliar char-
                                     acteristics of crop and weeds determine the selectiv-
                                     ity.  These herbicides are most effective on seedling
                                     weeds. Established grasses and biennial and  peren-
                                     nial broadieaved weeds may regrow after the foliage
                                     is killed. These herbicides are generally not trans-
                                     located and some may have a short effective life in
                                     the  soil.  Examples: endothall, dinoseb-salts,  Stod-
                                     dard solvent.
   Preemergtnce lo ihe
    Crop and Weeds
Poslemetged Crop
Preemerged Weeds
Postemergence ID ihe
 Crop and Weeds

   These herbicides kill all foliage contacted. Because
 they are nonselective,  they must  be  applied in the
 absence  of a crop  or  as a spray directed towards

                                       These herbicides are absorbed by the foliage and
                                     translocated throughout the plant.  Since  they  are
                                     nonselective, they cannot be applied when  a crop is

present, but they can  be used before  planting or
after harvesting. Examples; TBA, glyphosate.
chloropicrin, methyl bromide, calcium cyanamide.
                                                                                         2 DAYS
 Non persistent

  These herbicides are applied to the foliage and are
absorbed and translocated throughout the living por-
tions of the plant. Their selectivity results from the
ability  of some plants to deactivate the herbicides
and therefore they can be applied over  the top of
the crop. Selective translocated herbicides are most
effective when applied during the vegetative stage of
development of the weed. Examples: 2, 4-D; 2, 4,
5-T; MCPA; silvex; dalapon.

  A small number of herbicides belong to this group.
The most widely  used are fumigants, but there are
other chemicals also. Fumigants are gases at normal
air  temperature and escape into the air if the treated
soil is not covered. Most fumigants are released un-
der a sheet of plastic or other gas-tight cover which
remains for about 24  hours.  All  weeds and other
plants, including seed, are killed. These  are always
preplant applications. Examples: carbon  bisulphide,

  These herbicides are applied to the soil before, at,
or immediately after planting. Their active residues
last less than a year. Most herbicides used for vegeta-
ble  and grain crops are in this group. Since the crop
is present at the time the herbicide is applied, or is
planted soon after application, the herbicide must be
selective. The selectivity is usually due to differences
in the internal chemistry between the crop  and weed
species. These herbicides are often  called  preemer-
gence herbicides or preplant, soil incorporated her-
bicides. Examples: CIPC, EPTC, CDAA, substituted
ureas (diiiron, linuron,  monuron),  TCA, amiben,
trifluralin,  atrazine  at low rates.

                              6-8 WEEKS

  These herbicides are used to control all plants in
noncrop situations to maintain a bare ground. They
are  used on parking lots, around warehouses, along
fences and highway guardrails, and in storage areas.
Examples: bromacil, boron,  sodium, chlorate, and

 simazine and atrazine at high rates.
                    MORE THAN 1 YEAR

  These herbicides have a  low solubility in water
and do  not leach readily, so they stay  near the soil
surface. The selectivity is often based on the inability
to reach deep-rooted crops. They may be applied to
the  foliage of the weeds, although most of the  her-
bicide is eventually absorbed through the root  sys-
tem. They persist and  will  give weed control for
more than a year. Some can be used to control weeds
in fruit  trees, nut trees,  and grapes. Examples:  ter-
bacil, picloram, diehlobenil, simazine at low rates.

                   MORE THAN  1 YEAR
Controlling  Vertebrate   Pests

   Pesticides  used to control vertebrate  pests  are
often named for the type of animal they control.
Common pesticide categories include:
     • rodenticide—rodents,
     • avicide—birds,
     • piscicide—fish, and
     * predacide—predatory animals.
Pesticides for control of vertebrates niay be fumi-
gants,  chemical repellents, reproductive inhibitors,
baits, or broadcast poisons.

   Fumigants kill vertebrate pests in burrows, storage
bins, or other areas which can be easily sealed. The
pests cannot escape  and are  killed  by inhaling the
toxic gas. Examples are cyanide and methyl bromide.

   Chemical repellents may make treated areas unac-
ceptable to  pests by odor  or taste and thus deter
damage. In  this way, the offending animal may be
forced  to find a different location or new food source.
Examples are Mesurol, used as a repellent on seeds;
and napthalene, which repels  by odor.

   Reproductive inhibitors  that  control vertebrate
populations  show considerable promise with some
species. Research is continuing and the future may
see birth control  for pest species as an acceptable
means  of combating pest problems. An example  is
Ornitrol on  pigeons.
   Poison baits usually are in one of two  categories:
    •  multiple-dose  poisons (usually  anticoagu-
       lants), which must be eaten repeatedly during
       a period of several days to be effective.  Ex-
       amples  are Warfarin  and Pival for rodent
    •  single-dose poisons,   which  kill  quickly  if
       enough  is consumed  at one  feeding. Place
       baits so that they will  be eaten by the target
       pests but  not by other animals or  people.
       Avoid  secondary poisoning by  picking up
       carcasses  before  dogs, cats,  or protected
       predatory  animals find them. Examples are
       Avitrol for bird control, and zinc phosphide
       and Vacor for rodent  control.
                                                          POISONOUS BAITS

  Broadcast  poisons—A  few pesticides  registered
for use on vertebrate pests are formulated as wettable
powders or  emulsifiable  concentrates.  They are
sprayed on or released into the application site. The
target species present in or entering into the applica-
tion site are controlled.  Piscicides are usually in this
category. The chemical  is released into the pond or
stream and susceptible aquatic species are controlled.
Examples are endrin for rodent control and rotenone
for fish control.
  Few  pesticides are registered for use  on verte-
brates. Registered pesticides have labels which name
the offending or target species, details of application,
and precautions  to  be taken.  Poisons or  repellents
may not be used on species other than  those listed
on the label. Pay special attention to State and local
regulations, which may be more  stringent than Fed-
eral regulations.
               Pollution by Pesticides
                                  -  f -
   Many combinations  of  these  and other  factors
 may  lead  to  soil and  water problems. Use good
 judgment and seek good  professional  advice. Be
 aware that as  the risks in a given situation arise, you
 may need to consider changing time of application.
 pesticides,  or  your normal  application method.

 Soil  and  Water

   A number of factors are involved in the  risk of
 soil and water contamination.  On  crops  where re-
 peated pesticide applications are necessary, pesticides
 (especially  those that are persistent, such  as lead
 arsenate or copper) may build up in the soil.
   On row crops where tilling  is common and the
 water drains into aquatic areas, runoff  of contami-
 nated soil particles and pesticides is likely.  Do not
 apply pesticides just before predicted heavy rains or
 just before some types of  irrigation.
   Some protectant fungicide sprays should  be ap-
 plied  before and  during  a rain.  Some herbicides
 should be applied just before rain.  However, heavy
 rains  cause  runoff and tend to wash the pesticide
 away  from  the target area. The runoff can carry
 the pesticide into sensitive areas where crop injury
 may result. Runoff may also reach  farm  ponds,
 streams, and waterways, causing contamination, fish
 kills, or injury to domestic animals such as dairy

   Drift is  a  main cause of contamination of non-
 target areas.  Factors affecting drift include:
     * pesticide formulation,
     • particle size,
     • velocity and direction of wind,
     • type of application equipment used,
     • volatility of the pesticide, and
     • temperature inversions.
 A temperature inversion exists  when  cool  air  is
 trapped close to the ground by a warm layer of air.
 Particles released into the cool air layer at ground
 level have minimum upward movement. The slightest
 air movement can cause the particles to drift for
 great distances before they fall.
   In addition, the toxicity of the pesticide and the
sensitivity of  the nontarget  area  will influence the
potential damage.
   When other conditions are the same:
     •  Smaller droplets or dust particles drift farther
       than larger ones.
     •  There is more chance of drift with air blast
       sprayers than with boom sprayers.
     •  There is more chance of drift with  high-
       pressure  sprayers than  with  low-pressure
     •  Low-volume concentrates  are more likely to
       drift than high-volume dilutes.

     * ULV sprayers have one of the greatest poten-
       tials for creating drift because they produce
       very small droplets.
     • The chance of wind effect and drift increases
       as the boom or outlet is raised above the
     • Air currents which  may  cause drift  are us-
       ually greater during the  middle of the day
       than in early morning or  late afternoon.
     • High pressure  and  small  nozzle openings
       produce fine spray droplets which drift  more

Reentry ond  Prehorvesfr  Intervols

  The preharvest interval is the least number of days
allowed between the last pesticide  application and
the harvest  day. "Days to slaughter" and "days  to
grazing"  intervals  apply to livestock feeding. When-
ever these intervals are applicable, they  are listed on
the pesticide label. You should advise your customer
of the number of days involved for  each.

                 Days to Harvest
                                Al or Below
                               Tu lattice, ifie Dop]
                                Cijn be Sold far
                               'uod jrnl Feed
Deposit           Rt'biduo
       (Shading Denotes Pesticide Residue)
                  Days to Slaughter

                            Ai  Application

                                5 Days
                            After Application

                             Slaughter Day
                          At or Below Tolerance
              {Shading Denotes Pesticide Residue)
  The worker reentry period is the minimum time
between the last pesticide application and reentry of
workers into the field  without  protective clothing.
The worker reentry interval will be listed in the spe-
cial "reentry" section  on the new format pesticide
label. You should advise your customer of the num-
ber of days involved and the type of protective cloth-
ing that workers must  wear if reentry is  necessary
before the period runs out. Workers may not reenter
treated  fields without  proper protective clothing at
least until the sprays have dried or dusts have settled.
Proper (and legal)  minimum protective clothing for
early  worker reentry includes a hat or other suitable
head  covering,  a long-sleeved shirt and long-legged
trousers, shoes, and socks.
  Inform your customer of these intervals and reg-
ulations. Misunderstanding, injury, and possible lit-
igation  may result if your customer is not properly

                   Reentry Sign
                                                                              Do Not Enter

                                                                             This Area Until

                                                                           Wednesday, June 2

                                                                              Treated With

                                                                               De Pesto

   Phytotoxicity is  injury to plants which can range
from slight burning  or browning  of  leaves  to  the
death of the whole plant. Such injury to  plants by
pesticides may be the result of:
     • excessive dosage,
     • direct application to a susceptible plant,
     • drift onto the plant of spray, dust, or vapor,
     • runoff from a treated field,
     * persistent soil residues, or
     • improper formulation.
   Injury to the plant may appear as:
     • dead, burned, or scorched spots on or at the
       tip of leaves,

     • russeting of fruit,
     • misshapen fruit, leaves, or plants,
     • off-color,
     • stunting,
     • delayed development,
     • poor germination, or
     • complete death of the plant.
   Unfortunately, these signs of chemical injury often
do not appear until several days after exposure to
the pesticide. If they do appear, they are not always
clear-cut and often may be confused with other prob-
lems. It may  be necessary to call on experienced in-
dividuals to help  identify the cause.
   The likelihood of plant  injury resulting from the
use of a pesticide varies with:
     • the chemical,
     • the formulation,
     • the concentration,
     • the combination of chemicals,
     • method of application,
     • growing conditions, or
     • the growth stage or condition of the plant.
   Emulsifiable concentrates, which contain solvents,
are more likely to cause injury than wettable pow-
ders. Mixtures  of pesticides are more likely to cause
injury than the same materials applied individually.
High-pressure  applications may cause injury  when
low-pressure applications would not.
   Plants  growing under  stress conditions, such  as
those in shallow soils or wet spots, are more suscep-
tible  to injury than healthy plants. Young, tender,
fast-growing plants with much  new growth  tend  to
be more  susceptible  to injury.  Some varieties are
more sensitive than others.

Community  Problems

   Agricultural land close to urban development may
have  greater community problems than  an all-agri-
cultural area. Drift, phytotoxicity, and other nontar-
get injury can cause problems in any community, but
the denser  the human population or livestock ad-
joining treated areas, the greater the risk of injury  to
humans or domestic animals.
   When the crops on adjoining land are sensitive  to
the pesticides you are  using, be especially  careful  to
prevent drift.
   Aquatic areas, such as  ditches, ponds, or lakes,
are particularly sensitive to pesticide contamination.
Where reservoirs for community water supplies, fish-
ing, and  other  public uses are  involved, careless
pesticide  application  may cause  fish  kills or con-
taminated water supplies.
                                                                 «U.4. OOVBRMMHIT PRINTING OFFICE !  1978 0-720-335/6040