United States
Department of
Agriculture
Animal and
Plant Health
Inspection
Service
Environmental
Protection
Agency
proceedings of the
Symposium on the Imported Fire Ant
June 7-10, 1982
Atlanta, Georgia
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This publication is the result of a Symposium called and sponsored by the
U. S. Environmental Protection Agency and the U. S. Department of
Agriculture, Animal and Plant Health Inspection Service. The opinions,
conclusions and recommendations are those of the participants and are
advisory to the two agencies. The papers published herein have been
printed as submitted and have not been subjected to review by either
agency prior to publication; therefore, the views expressed do not
necessarily reflect those of EPA or USDA, and no official endorsement
should be inferred.
Trade and company names are used in this publication solely to provide
specific, information. Mention of a trade or company name does not
constitute a warranty or an endorsement by the U. S. Department of
Ariculture to the exclusion of other products or organizations not
mentioned.
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PROCEEDINGS OF THE
SYMPOSIUM ON THE IMPORTED FIRE ANT
June 7 -10, 1982
ATLANTA AMERICAN HOTEL
ATLANTA, GEORGIA
SYMPOSIUM COORDINATOR:
Fred H. Tschirley
EDITOR:
Susan L. Battenfield
ORGANIZED AND MANAGED BY:
Jhter-Society Consortium far Plant Protection
SPONSORED BY:
Environmental Protection Agency
USD A, Animal, Plant Health Inspection Service
September 1982
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ACKNOWLEDGEMENTS
There are always many who contribute
to the success of any endeavor. That is
especially true for the Imported Fire Ant
Symposium because its conception, gesta-
tion, and birth occurred in such a short
time. Labor pains were particularly intense
for panel chairmen. They were first con-
tacted during the last full week in March.
That they agreed readily to devote time to
an important public issue commends their
professionalism and their sense of responsi-
bility to society. We are grateful for their
efforts. Equal dedication was exhibited by
panel members. The Symposium would not
have been possible without the time and
talent they contributed so unstintingly. All
chairmen and members of panels are listed
in the appropriate panel reports. We owe
each a debt of gratitude.
The unsung heroes of any large meeting
are always those who arrange the amenities
most of us take for granted. Travel ar-
rangements, hotel accomodations, meeting
rooms, and a host of other details don't
simply happen. They were provided by the
untiring efforts of the business office of the
Inter-Society Consortium for Plant Protec-
tion, in the persons of Raymond Tarleton
and his able, ever pleasant assistant, Dottie
Ginsburg. A principal factor in keeping the
Coordinator coordinated was my secretary,
Doreen Kebler. Her assistance was invalu-
able.
Attention to numerous details during the
Symposium, editing, and processing this re-
port required the sure touch of Susan Bat-
tenfield. Panel reports written rapidly and
under stress during the course of the Sympo-
sium necessarily required editorial skill.
The results of Susan's efforts are apparent.
Her assistance was invaluable.
Lastly, the genesis and support of the
Imported Fire Ant Symposium came from
the Environmental Protection Agency and
the Animal Plant Health Inspection Service
of the U.S. Department of Agriculture.
That they recognized the fire ant and its
management as a serious scientific, social,
and political issue was expected. That they
joined forces to host a Symposium at which
the many diverse attitudes and points of
view relating to management of the fire ant
could be discussed openly was not expected.
Their willingness to risk criticism in an open
forum signifies a maturity of judgment and
an awareness of social responsibility that
augers well for the resolution of honest
disputes in the future. We commend their
action and hope that other agencies, organi-
zations, and groups, whether they be gov-
ernmental, the federal, state or local level,
or in the private sector, will recognize the
ii
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value of open discussion of differences in a
spirit of resolving disputes rather than per-
petuating them through an adversarial pro-
cess.
Many others contributed importantly to
the success of the Symposium. Failure to
mention their contributions does not reflect
insensitivity to their help, rather a con-
straint of time and space. We are indeed
grateful to all.
Fred H. Tschirley
Coordinator
ill
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TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY 1
OPENING REMARKS
Charles Jeter, EPA 9
John Ferris, ISCPP 10
John Todhunter, EPA 11
Jim Lee, USDA 13
Walter R. Tschinkel, Florida State University 16
Reagan Brown, Commissioner of Agric., Texas 36
Carolyn Carr, Sierra Club 40
PANEL REPORTS
I. Socio-Economic Factors Relating to the IFA and its
Management(J. Charles Headley, Chairman) 41
II. The Theory of Population Dynamics (Dean L. Haynes,
Chairman) 51
III. Population Dynamics of the IFA (Fowden G. Maxwell,
Chairman) 67
IV. Environmental Toxicology (Robert L. Metcalf, Chairman) . . 75
V. Management of Established vs. Introduced Pests (Harold T.
Reynolds, Chairman) 82
VI. IFA Management Strategies (Richard J. Sauer, Chairman) . . 91
LIST OF REGISTRANTS
APPENDICES
A. Chemistry and Properties of Fire Ant Venoms (Murray S.
Blum) 116
B. The Medical Aspects of the Imported Fire Ant (William H.
Schmid, Allergist) 119
C. A Brief History of Chemical Control of the Imported Fire
Ant (R. L. Metcalf) 122
D. Impact of the Imported Fire Ant Control Programs on
Wildlife and Quality of the Environment (Maureen K.
Hinkle) 130
E. Ferriamicide: A Toxicological Summary (Earl L. Alley) . . . 144
F. A Brief Overview of the Requirements for Pesticide
Registration (D. J. Severn) 154
iv
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Table of Contents (continued)
Page
G. Environmental Toxicology of Pesticide Application
Programs (H. N. Nigg) 157
H. Models for Decision-Making (John Wood) 159
I. Chemicals Currently Under Investigation for Possible IF A
Use (Panel IV) 161
J. Comments on Ferriamicide and the IFA Problem (Mississip-
pi Department of Agriculture and Commerce) 187
K. Fire Ant Fact Sheet (EPA) 190
L. Eradication: An Assessment of Concept and Practice (Ed-
ward N. Smith) 201
M. Biological Control: Its Historical Use vs. Prospective Value
to Control the Imported Fire Ant (Frank E. Gilstrap)... 214
N. Impact and Management of Introduced Pests in Agriculture
(Marcos Kogan) 226
O. Some Considerations for the Eradication and Management
of Introduced Insect Pests in Urban Environments
(Gordon W. Frankie, Raymond Gill, Carlton S. Koehler,
Donald Dilly, Jan O. Washborn, Philip Ham man) 237
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Executive Summary
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EXECUTIVE SUMMARY
Fred H. Tschirley
INTRODUCTION
The imported fire ants (IFA), SoZenopsis
richteri Forel and Solenopsis invicta Buren
were introduced from South America into
the United States in the early 1900's and the
late 1930's, respectively, at the port of
Mobile, Alabama. Their area of infestation
has expanded dramatically since introduc-
tion. In the late 1940's and early 1950's,
they were present from Miami, Florida,
west to San Antonio, Texas, and north to
Memphis, Tennessee, and eastern North
Carolina. Today, they are found on about
240 million acres in 10 states. S. invicta,
the red fire ant, occupies over 95% of the
infested area; S. richteri, the black fire ant,
is found in northern Mississippi and Ala-
bama. The spread of the IFA has occurred
despite extensive state and federal pro-
grams designed for its control.
The potential future distribution of the
IFA is open to some question. There is
general agreement that northward extension
of the present area of infestation has
reached its limit, although some extension
may occur along the eastern coast. West-
ward spread cannot be accurately predicted
because all of the biotic and abiotic factors
influencing establishment are not known.
Warm rains, which occur in New Mexico and
Arizona, are necessary to trigger mating
flights and ensure nest excavation. South-
ern California lacks summer rains, but has
extensive irrigation acreage that may
trigger mating flights. Thus, expansion of
the IFA range westward to California and
then northward along the coast through
Oregon and Washington is not certain, but
neither is it improbable.
NATURE OF THE PROBLEM
IFA infestations occur in many habitats:
field and vegetable crops, nurseries,
orchards, hay fields, forests, and unmanaged
wildlands. That the IFA is a pest is unques-
tioned; that it is truly an economic pest of
agriculture has not been adequately docu-
mented.
Data concerning the agricultural impact
of the IFA do not support a conclusion of its
being an economic pest, although reports
indicate livestock losses from IFA stings.
Other reports document reductions in hay
yield and quality, and yield reductions for
field crops (soybeans) where ants are abun-
dant or where seed has not been well
covered at planting. Damage to equipment
and conversion to alternate harvesting
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equipment (hay, for example) due to IFA
mounds are unquestioned adverse economic
impacts. The IFA are a nuisance for crops
that are hand-harvested, but no studies have
documented the economic impact of this
factor. On the other hand, the IFA is
considered to be a key predator of Heliothis
species in cotton production, is an excellent
predator of the sugarcane borer (saving
growers one or two insecticide applications
per season), preys on the banded cucumber
beetle and sweet potato weevil in sweet
potatoes, and is an important predator of
many detrimental insects in soybeans. The
IFA is also an excellent predator of ticks,
hornflies, and stable flies. In many areas
IFA predation has reduced lone star tick
populations to the point where they are no
longer considered to be an economic pest.
Although costs and benefits of IFA in
agriculture have been documented, the
available data base is too limited to permit
a conclusive cost/benefit analysis. An eco-
nomic analysis of one county in Florida
established a cost/benefit ratio of 5.6:1, but
the extent to which that study can be
extrapolated to other agricultural areas is
unknown.
Young birds and other forms of wildlife
that nest on or in the ground are vulnerable
to IFA attack during their early hours of
life. There are documented cases of young
quail and newly born rabbits being killed by
the IFA, but there is no indication that
populations of those species have been
reduced.
Human health consequences may be the
most important adverse effect of IFA infes-
tations. Because urban as well as rural
areas are infested, about 40 million people
are in potential conflict with the IFA. The
IFA was so named because the venom
induces a painful, fiery sensation. The ant
grips the skin with its mandibles and may
sting its victim multiple times in a circular
pattern around the point of mandible
attachment. The aggressive nature of the
ant when a mound is disturbed commonly
results in attack by numerous ants so that
10 to 30 stings are common. Many people
experience only local reaction and tempor-
ary discomfort. In others a sterile pustule
develops within 24 hours, which is clinically
diagnostic. Although the venom is bacteri-
cidal, secondary infections as a result of
scratching may occur. A small percentage
of persons stung, probably 1% or less, exper-
ience a systemic anaphylactic reaction of
variable severity. Some such individuals
may require hospitilization, and the reaction
may be life threatening. One author cites
17 deaths due to fire ant venom. Hypersen-
sitive individuals can be desensitized.
The perceived severity of the IFA as a
nuisance or public health pest problem was
delineated in two telephone surveys con-
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ducted by the American Cyanamid Corpora-
tion in 1980 and 1981. The surveys indi-
cated that about one million households
treated with insecticides for IFA control;
the balance (22%) were using gasoline, boil-
ing water, or cultural methods; 73% of the
respondents treated lawns, 58% gardens,
54% pastures, 19% row crops, and 4%
woods. The higher percentages recorded for
lawn and garden treatment suggest that
nuisance and public health reasons are the
primary motivations for treatment because
an economic return would not be expected
for those habitats, especially lawns.
PESTICIDES FOR IFA CONTROL
Large-scale eradication programs for the
IFA were initiated in 1958. Heptachlor and
dieldrin were applied at a rate of 2 Ib. per
acre (later reduced to 1.25 Ib. per acre) to
about 20 million acres over a 5-year period.
Effects on wildlife species were disastrous
and were a significant reason for public dis-
enchantment with the use of pesticides.
Despite the massive eradication attempt,
the area infested by the IFA increased from
90 to 126 million acres during the 5-year
period.
Mirex, applied in a bait, represented a
decided improvement over the previous
treatments because the rate of the active
ingredient could be reduced to 1.7 grams per
acre (0.00374 Ib. per acre) without reducing
IFA control. A massive eradication pro-
gram, over a 12-year period, on the entire
126 million acre area of infestation was
planned at a cost of $200 million. Problems
arose, however, when mirex was found to be
persistent in the environment, bioaccumula-
tive, and later shown to cause hepatocarcin-
omas in mice. Subsequently, the use of
mirex was lessened until 1978 when all in-
secticidal uses were cancelled.
Ten insecticides are currently registered
for IFA control by broadcast application on
non-agricultural crops, for mound treat-
ment, and for treatment of nursery stock;
several have conditional registration or have
registration pending. In addition, five insect
growth regulators are being developed for
possible use as IFA control agents. More
detail for the products is provided in Appen-
dix I. The toxicant of greatest concern is
ferriamicide. Mirex is the active ingredient
in ferriamicide, but the formulation
contains amine and ferrous chloride
components to reduce environmental persis-
tence and propylene glycol to suppress the
production of chlordecone, a degradation
product. Ferriamicide does indeed have a
shorter environmental half life; however,
the presence of chlordecone in shelf samples
and the discovery that photomirex is a
degradation product of ferriamicide
immediately caused concern. Both chlorde-
cone and photomirex are highly toxic and
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carcinogenic in test animals.
CURRENT MANAGEMENT OPTIONS
The technology now available for manag-
ing the IFA in a variety of habitats is
limited. Insecticides are the primary man-
agement tool; 16 are now registered for one
or more uses of which two have state
registrations under Section 24(c) of the
FIFRA, and 3 have experimental use
permits. Seven have a registration or a
request for an experimental use permit
pending. Boiling water is appropriate for
some limited situations. Mound leveling can
be effective, but the necessity for timing
the treatment just before freezing
temperatures occur limits the effectiveness
of the method severely.
There is agreement that an educational
program needs to be conducted to ensure
that necessary and accurate information
about the IFA is available to the public.
The need is dictated by the fact that the
IFA is an emotional issue; therefore, accur-
ate, objective, and unsensationalized infor-
mation assumes even greater importance.
In all educational efforts, a distinction
should be made between perceived problems
and demonstrable effects.
THE ENIGMA
The red fire ant has been in the U.S. for
about 50 years. Serious efforts to control or
eradicate the pest have occured during the
last 25 years. Despite the passage of time
and the expenditure of more than $100 mil-
lion of local, state, and federal funds to
control the IFA, the area of infestation is
larger than ever before and is growing.
Moreover, the magnitude of the IFA prob-
lem cannot be defined with any degree of
precision. There are both costs and benefits
to agriculture associated with the presence
of the IFA. In urban situations, where there
is a greater probability of IF A/human con-
tact (and therefore conflict), the IFA has no
demonstrated benefits, but the costs in
terms of public health considerations are
not inconsequential. Some half dozen chem-
icals used for IFA control have been
cancelled, others are currently registered
for specific situations, and still others are in
the developmental process with hope of
eventual registration. Biological control of
the IFA is not now possible; physical and
cultural manipulation, once thought to deter
colony establishment, now appear to be
generally ineffective; flooding and burning
do not destroy or kill IFA colonies. Inte-
grated pest management, defined as the use
of a variety of management methods, can
only be applied intellectually because only
chemicals have given temporary relief.
Nevertheless, logic dictates that some non-
chemical control is operating. Mound
density varies within the range of infesta-
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tion, even in disturbed areas that are known
to be more readily invaded. Present knowl-
edge, however, cannot identify the opera-
tive factors.
In terms of information presented, the
IF A Symposium was more notable for its
exposition of what is not known but needs to
be known, than for what is known—a
humbling comment on the wisdom of
humans. Consider if you will (1) Panel I's
two-plus pages listing the types of data
needed to estimate the costs and benefits
associated with the IF A; (2) twelve specific
research recommendations in Panel in for
developing information that must be known
before informed management strategies can
be applied in a diverse set of habitats; (3)
seven specific recommendations by Panel IV
to elucidate toxicologic questions relating
to the IFA venom and to insecticides used
for control; and (4) another seven recom-
mendations from Panel VI, which quickly
discovered that chemicals are the only
proven technology available for manage-
ment! Adding the recommendations of
Panels n and V, whose subject matter was
much broader than just the IFA, completes
the litany of the unknown. How can one
avoid being impressed, annoyed, frustrated,
and dumbfounded by such a comprehensive
exposition of our ignorance?
The litany of the unknown should not
cast a shadow of reproach on research that
has been done on the chemistry of the toxin,
the biology of the IFA, and methods for its
control. The literature on the IFA contains
numerous papers describing exemplary
research, which forms the basis for what we
know about the IFA today. In addition,
carefully crafted research programs have
been recently initiated that have promise of
soon answering many of the questions that
remain unresolved. A valid criticism of past
efforts is that research lagged far behind
action programs. Even today, many states
within the area of infestation do not have an
active IFA research program. Only recently
has there been a comprehensive review of
IFA research, which forms the basis for a
research effort that is broader in scope and
addresses critically important areas of
knowledge that are now wanting.
FUTURE DECISION-MAKING
A message coming through clearly from
the symposium is that population and com-
munity dynamics of a pest, whether native
or introduced, involve an extremely complex
interaction of biotic and abiotic compo-
nents. Any program designed to deal with a
pest, whether it be doing nothing on one
extreme to eradication attempts on the
other extreme, carries an element of uncer-
tainty and may result in failure. The proba-
bility of failure necessitates conducting an
integrated research program concurrent
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with the earliest management programs.
The management program must be flexible
in the sense of changing strategies as knowl-
edge of the pest and its interactions with its
environment evolves.
This does not imply that decision-makers
should or will have the luxury of doing
nothing until adequate knowledge is devel-
oped to permit an adequately informed
course of action. It does mean that deci-
sion-makers should anticipate the possibility
of major modifications based on the infor-
mation developed by a concurrent research
program, rather than establishing policy (a
plan to deal with a pest) and then designing
a research program that supports the policy.
The importance of early detection of a
pest is paramount. A new pest that is
geographically restricted and numerically
limited may be handled relatively easily.
There are notable examples of successful
pest eradications while the pest's geographic
range of infestation was still limited. The
failure of eradication efforts against pests
that were widely established are equally
notable. In that context, the fact that
about 84% of newly-detected homopterans
in California originated from urban infesta-
tions is a matter of prime importance (Ap-
pendix O). It begs the question of whether
monitoring efforts for new pests should be
concentrated in urban areas. If data for
homopterans can be extrapolated to other
pests species, we must also consider that
eradication will be more difficult in densely
populated areas. Moreover, by the time a
serious pest is detected in an agricultural
area, the population may already be suffi-
ciently large and geographically extensive
to severely limit management options.
Our society has a reputation of being
overly enamored with "quick-fix technol-
ogy." Define the mouse and we'll build a
better mousetrap. That sort of engineering
approach to resolving problems is fraught
with many difficulties when applied to the
biological realm. The quick-fix is, however,
an important component of our society's
consciousness. Its power as a driving force
must be recognized. Persons affected by a
perceived threat, whether relief from a nui-
sance or protection from an economic or
public health threat, demand action. Those
who provide funding at the local, state, and
federal levels to support programs in re-
sponse to public demands are mightily
attracted by quick-fix technology because it
promises to solve the problem quickly. Even
if the problem is not resolved, the overt
show of force that characterizes quick-fix
solutions demonstrates a responsiveness to
public concerns.
Modifying the quick-fix response by pub-
lic decision-makers will not be easy. Single-
issue politics is a potent force in our
society. Would public decision-makers in
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the early and mid 1950's have survived a
decision to allocate funds equitably between
an action program and a comprehensive
research program on the IFA? The question
is rhetorical, but important. The wisdom of
hindsight permits the conclusion that, had
an equitable allocation of funds between
research and eradication occurred in the
1950's, the IFA would probably still be a
problem, but most likely it would not be the
pervasive scientific-social-political issue
that it is today.
Because so much is yet unknown about
the IFA, a decision on fund allocation now is
not substantially different than it would
have been in the 1950's. We, however, do
have the advantage of knowing that the
eradication attempt was not successful.
Yet the problem of the IFA remains and
its geographic range of infestation will
probably spread beyond its current limits.
What an ideal opportunity, having the IFA
Symposium for support, to develop an
action-education-research program designed
by the best minds available from the scien-
tific, educational, social, and political sec-
tors. A good beginning has been made
toward establishing communication among
the various sectors of society involved in
the fire ant issue. If that communication is
now aborted, the IFA Symposium will have
been just another meeting of concerned citi-
zens without any perceivable impact on the
affairs of humans.
One looks to the future and wonders
what and how decisions will be made about
the inevitable serious pest we will have to
deal with in the years ahead. The agencies
that supported the IFA Symposium have a
stake in the unknown pest scenario of the
future. While EPA's primary responsibility
relating to pests is the registration of pesti-
cides, the agency also has a responsibility to
comment on environmental impact state-
ments. It cannot do so intelligently without
an acute awareness and appreciation for
biology and all its complexities—the data
needs and the correct questions to be asked
for informed decision-making. USDA has
broad responsibilities for research and edu-
cation relating to pests, and it is directly
involved in conducting quarantine, pest
management, and eradication programs.
The decisions USDA must make are difficult
scientifically, socially, and politically.
Decisions must be based on sound knowledge
of biological and ecological components.
Both agencies can benefit from drawing on
the large and diverse body of expertise
resident in the land-grant college system
and other academic institutions. Decisions
made in isolation are breeding grounds for
dispute. Decisions based on a broad founda-
tion of knowledge are much more likely to
avoid dispute.
The process of direct communication
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among those with different opinions on how
to manage the fire ant, which was the
guiding principle of the IFA Symposium,
provided encouraging indicators that dis-
putes can be resolved through discussion of
differences in a non-adversarial setting.
Occasional sharp exchanges among those
with differing points of view were welcome
events. Such exchanges must occur before
understanding of a different position and
then resolution of differences are possible.
Clearly, neither broad scale eradication at-
tempts by using insecticides nor a complete
cessation of chemical control are tenable
management options for the IFA. That a
single symposium will heal the wounds
inflicted over many years of adversarial
strife is a vain and overly sanguine expecta-
tion, however. Dialogue among disputants
must continue and expand if the success of
the IFA Symposium is to have lasting
impact.
Guidelines for decision-making relating
to the IFA, to other current pests, and those
of the future are contained as recommenda-
tions in the panel reports of the IFA Sympo-
sium. I commend to you those recommenda-
tions. The broader issue, implicitly
addressed by the Symposium, is a method-
ology for dispute resolution. Dispute cannot
and should not be avoided; our ability to
resolve dispute must be at the top of soci-
ety's priority list. To that end, the IFA
Symposium has been a hopeful beginning.
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Opening Remarks
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WELCOMING REMARKS
Charles R. Jeter
EPA Regional Administrator
Atlanta, Georgia
Welcome to Atlanta, the fire ant capital
of the world, at least for this week. Seri-
ously, the Intersociety Consortium has put
together a very impressive program. It is
my hope that we will end the week with
some answers on how to deal with the
imported fire ant problem. The experts are
here. It should be a productive week.
I will not take much of your time, but I
would like to take this opportunity to re-
mind you that the overriding mission of the
Environmental Protection Agency is to safe-
guard the health of the American people and
to protect our natural environment. This is
the mission for which EPA was founded and
the cause to which this Administration is
dedicated. Good science is one of the
Agency's goals. That, along with regulatory
reform, improved management, elimination
of backlogs and strengthened partnerships
with state and local governments, will help
us fulfill our mission.
Good science is a key element. We
believe that there cannot be good regulation
without good science. Without adequate
scientific understanding, steps necessary for
the protection of human health might never
be taken.
Our concern for better application of
science has led to a more comprehensive in-
volvement of EPA's science advisory board
in the development of new regulations. This
body of eminent American scientists will be
asked to review the scientific adequacy of
Agency regulations and generally become
more involved in Agency activities. As part
of this new approach to the better use of
information we are aggressively seeking
peer review of Agency scientific reports.
Other actions in this area include the
preparation of health assessments for seven
chemical solvents. The information will be
submitted to the Science Advisory Board for
public and peer review. Several other pro-
jects that influence the Agency's approach
to health and risk assessment are in varying
stages of completion.
We've made significant gains in the other
areas mentioned earlier, but there's no time
to elaborate. I wanted especially to men-
tion our attempts to improve the quality of
our science and to underscore that EPA now
insists that any proposed regulation whose
rationale depends on scientific assumptions
is subjected to a thorough peer review by
knowledgeable scientists to test the validity
of those assumptions.
Again, welcome to Atlanta. Come visit
the regional office while you're here. And
have a good meeting. Thank you.
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OPENING REMARKS
John Ferris
President
InterSociety Consortium for Plant Protection
I am here this morning by virtue of my
position as chairman of the Executive Coun-
cil of the InterSociety Consortium for Plant
Protection (ISCPP). The Consortium is
made up of representatives from the four
main U.S. plant protection societies: Ento-
mological Society of America, American
Phytopathological Society, Society of Ne-
matologists, and Weed Science Society of
America. Each of these societies is repre-
sented on the Executive Council by their
Vice-President (or President-elect), Presi-
dent, and immediate past President. The
Executive Council of the ISCPP meets two
or three times each year in Washington,
D.C. One of our objectives is to "provide
sound scientific advice to organizations and
agencies concerned with establishing poli-
cies, regulations and improved methods for
plant protection." And this is our role, our
involvement, in organizing this Imported
Fire Ant Symposium.
The subject matter of the panels has
been selected with the intention of covering
all aspects of the IF A problem. Dr. Fred
Tschirley, symposium coordinator, will go
into detail with you about the topics as-
signed to each panel, and how the
symposium is to proceed. What I wish to
emphasize now is that many of the panel
members, who are also members of one or
more ISCPP constituent societies, are here
as agricultural research scientists. You can
expect to hear from them what they believe
to be the latest facts about the fire ant.
However, there are two caveats you
should be aware of: the first is that a given
set of scientific facts can be used to support
divergent conclusions by twisting, distor-
tion, or selected emphasis of these facts.
The second is that what seems to be scienti-
fically true today may no longer seem to be
true at some future time because of new
evidence or better interpretation of existing
data.
What this symposium is striving for is an
unbiased presentation of the scientific
facts, as we now perceive them. These
facts can then be used to determine what
additional information is needed to solve the
fire ant problem on a long-term basis. And
this will probably require a lot of additional
research to provide some very specific bits
of information. A more immediate goal of
this symposium is to provide decision mak-
ers with the information necessary to deal
with the IFA on a daily basis until a holistic
approach to control this pest can be
developed.
10
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OPENING REMARKS
John A. Todhunter
Environmental Protection Agency
It's a pleasure to be here with you in
Atlanta this morning. I must confess,
though, that not being from this region, I
was reminded of the story of the Yankee
fisherman who, fancying himself the com-
plete angler, journeyed south of the Mason-
Dixon to test his skills in your lakes and
rivers. He had for a guide a Senior Southern
Gentleman named Homer who knew better
than anyone what was biting and where.
After a few outings and major successes,
our Yankee angler, not crediting Homer
with contributing to any of his success,
struck off for a stream that Homer knew
had no fish. The Yankee cast out into the
current which quickly took his line down-
stream. The angler began to reel in and met
resistance. Quickly he pulled to set the
hook and cried out to Homer "I got it, I got
it! And Lord is it strong!" Well, old Homer
stepped out into the stream and saw that
the line was snagged around a submerged
boulder that had been there since the Ice
Age. Homer yelled, "You got it, all right,"
to the Yankee fisherman. "You got old
Dixie and a helluva git you got1"
I guess that story has several morals, but
the one I had in mind is the one that teaches
us that for all our experience and expertise,
we can still learn more. That is why I
congratulate Charles Jeter, John Ferris,
Harry Mussman, Walt Tschinkel, Reagan
Brown, Carolyn Carr, Fred Tschirley and all
of you for making this symposium on the
imported fire ant a reality.
The imported fire ant, as Jim Buck Ross
once observed, is just what it is: imported—
the black ant variety from Uruguay, and the
red ant from Brazil. They have been around
since the twenties and thirties, and by the
fifties they began to move beyond their
point of entry around Mobile to nine south-
ern states and Puerto Rico. The fire ant,
imported or not, has become a major prob-
lem for the people of the South. Over 230
million acres are now infested. Their sting
has been felt by humans and livestock in the
thousands. Millions of dollars in crop losses,
medical expenses and in means to combat
them have been incurred.
With apologies to Pogo, we have met the
enemy and this time, they aren't us. So why
this symposium? You may recall that last
February, I announced that EPA and USD A
would sponsor a Symposium on the Imported
Fire Ant. This decision was prompted by
the State of Mississippi's application for
conditional registration of the insecticide
11
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12
Ferriamicide. It became clear to me at that
time that we could not evaluate the Ferri-
amicide application in isolation from all of
the many issues that surround the control of
the fire ant. What we needed then and need
now is information. And we expect we will
receive that information from the partici-
pants of this Symposium. In essence, what
we have today assembled is a multi-disci-
plinary task force of experts. Their task,
over the next four days, is to examine the
fire ant and the best possible method to rid
ourselves of its harmful effects.
This is no simple charge, as we are all
aware. Because there is no simple, risk-free
solution to this problem that we know of.
But try we must. Because our efforts here
will affect the decisions of the EPA and
USDA in this matter.
As you begin your deliberations, I ask
you to consider a number of things. First,
keep in mind that FIFRA is a risk benefit
statute not a zero-risk statute.
Second, remember that regulatory deci-
sions in the final analysis are subjective.
There are a number of considerations that
affect them—not the least is the level of
risk that our citizenry is willing to accept.
Third, consider the impact of science on
the regulatory process. Simply put, it is not
possible to make a good regulatory decision
that is based on bad science.
I am not asking you for unanimity, I
know better than that.
What I am asking you for is your best
scientific effort, leaving behind partisanship
and past disagreements. Because what we
produce by way of information at this Sym-
posium will not only play a powerful role in
the decisions of EPA and the USDA, but will
affect for many years to come the environ-
ment of the South and the lives of its
inhabitants.
I wish to thank you all for your partici-
pation and anticipate your guidance in this
matter.
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INTRODUCTION BY THE ANIMAL AND PLANT HEALTH
INSPECTION SERVICE, CO-SPONSOR OF THE SYMPOSIUM
ON THE IMPORTED FIRE ANT
James O. Lee
Associate Administrator
VSDA, APHIS
Good morning! We are pleased to be co-
sponsoring the Symposium on the Imported
Fire Ant here in Atlanta this week. Dr.
Mussman sends his regrets for being unable
to be with you today and sends his best
wishes for the Symposium.
Two species of imported fire ants were
brought to the United States about 40 to 60
years ago, and they have become a pest of
agriculture, a health hazard, and a nuisance
to those persons in infested areas. The U.S.
Department of Agriculture (USDA), Animal
and Plant Health Inspection Service
(APHIS), and Plant Protection and Quaran-
tine (PPQ), are responsible for program ac-
tions designed to locate the ants through
survey activities, to prevent or retard long
distance spread through the application of
regulatory procedures, and to reduce popu-
lations by applying control treatments, me-
thods development, and environmental mo-
nitoring.
The imported fire ant can cause eco-
nomic losses to agricultural lands as well as
nuisance and health effects to humans. Ag-
ricultural economic losses due to fire ant
damage are based on surveys and from ex-
trapolation of data. The agricultural losses
attributable to the imported fire ant have
been documented for most of the affected
states. In Florida, Georgia, and North
Carolina, losses due to reduced efficiency of
mechanical reaping of soybeans and damage
to equipment have been reported.
Estimates of losses ranged from $2.43 to
$4.70 per acre, when the yield of infested
fields was compared with that of uninfested
fields. Reports of other crop damage
include destruction of corn in Mississippi,
Alabama, and Florida; okra in Florida; and
peanuts and other crops in Alabama. In
addition to the direct damage to plants and
equipment, the presence of the imported
fire ants in a field reduces worker producti-
vity.
Individual adverse human health effects
occur from the imported fire ant by: (1)
causing discomfort, irritation, and the for-
mation of a pustule at the site of the sting;
(2) secondary infections that may occur at
the site of the pustule and that may lead to
gangrene and subsequent amputation of the
affected appendage; (3) mortality in certain
hypersensitive individuals; and (4) limiting
normal work and recreational activities in
heavily infested areas. Individual responses
to stings range from very mild localized
reactions of redness and tiny pustule for-
13
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14
mations, to severe systemic reactions that
require hospitalization and medical treat-
ment. These responses depend on the initial
sensitivity of the individual to imported fire
ant venom and to increased sensitivity that
may develop as a result of multiple sting
episodes.
Several sets of alternatives for control
of the imported fire ant have been consi-
dered, including alternative control agents,
alternative methods of application, admini-
strative alternatives, and alternative fund-
ing sources. The control of imported fire
ants may be achieved by the use of chemi-
cals, by biological means, or by other me-
thods. To date, greatest emphasis has been
placed on the development and testing of
chemical control insecticides. Chemical
toxicants may be classified as: (1) proven
agents, the use of which have been restrict-
ed or banned; and (2) new agents that have
not been applied on a large scale. Unfortu-
nately, there is no in-between at the present
time.
The imported fire ant control program
may be administered in several alternative
ways: a federal program, a joint
federal/state initiative, or independent
state programs. A program administered
exclusively by federal agencies is thought to
be undesirable. On the other hand, a series
of independent state programs would
probably not yield optimum results. State
boundaries are man-made and are not
recognized by the imported fire ant. The
optimum administrative approach therefore
would be a federal program involving state
governments and agencies. In this way, the
wishes of individual states may be respected
while the resources of all are pooled to
formulate a cohesive overall control
program.
The statutory authorities vested in the
U.S. Department of Agriculture pertaining
to program actions concerning the imported
fire ant include the following:
- Organic Act of the Department of
Agriculture, September 21, 1944, as
amended (Title 7, USC, section 147a);
- Plant Quarantine Act of August 20,
1912, as amended (Title 7, USC, sections
151-165, 167); and
- Federal Plant Pest Act of May 23, 1957,
as amended (Title 7, USC, sections
150aa-150JJ).
The imported fire ant control program
may be funded by the federal government,
state governments, or private citizens
(farmers and householders). Historically,
funding of programs has been shared
between states and the federal government.
Based on an analysis of alternatives, the
preferred alternative for control of the
imported fire ant is one that uses an
available and environmentally safe material
applied by an effective yet comparatively
inexpensive method. The aim of the
cooperative imported fire ant program is to
locate infestations of imported fire ants
through visual surveys, to retard the spread
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15
of imported fire ants by regulating specified
articles that are known to present a risk of
spread, to reduce the likelihood of other
areas becoming infested, and to control the
ant population in areas already infested.
Remaining issues and concerns identified
are; concern for human health and well-
being resulting from increasing ant
populations, that agency program actions
should have total eradication of imported
fire ants as the objective rather than
control, restrictions on the use of pesticides
to their fullest potential reduces the
likelihood of complete control, a need for
continued federal/state cooperative im-
ported fire ant program, concern for the
environmental effects of using a pesticide,
and concern about long-term effects of
using an insecticide that has not been fully
tested.
USDA/APHIS continues to have a great
concern for the impact of the imported fire
ant. The future of any operational control
program remains in the hands of all of us.
Thank you for your time and good luck for
the rest of the week.
-------
HISTORY AND BIOLOGY OF FIRE ANTS
Walter R. Tschinkel
Florida State University
In the time available, it is not possible to
summarize fire ant biology in detail, and
even if it were, such detail would probably
defeat the purpose of this keynote address.
Instead, I have chosen to make a more
conceptual interpretation of the available
facts about fire ants and to use these facts
to paint a general picture of the biological
nature and function of fire ants. The inter-
pretation is not an exclusive one, even
starting from the facts available. Consider-
ing the number and size of our gaps of
knowledge, the future may very well see
changes of interpretation.
The facts upon which I base my talk are
the results of the work of many people over
more than three decades. Complete attri-
bution is impossible in such a short review,
and to those who feel inadequatedly cited, I
apologize.
Because there are many non-biologists in
the audience, let me begin with a brief
description of the individual and colony life
cycles. Fire ants belong to the insect order
Hymenoptera, which also includes the bees
and wasps. As a result, the three groups
share most of the major life cycle charac-
teristics. Most importantly, fire ants, like
other Hymenoptera, are holometabolous;
that is, they develop through a complete
metamorphosis. The individual begins life
as an egg, which hatches into a legless,
grublike larval stage. The larva is a stage
specialized for feeding and growing, and
almost all growth occurs during this period.
As in all insects, growth is accomplished by
periodic molting, or shedding of the cuticle
(skin). Having reached its final size, the
larva undergoes a metamorphic molt and
becomes a pupa in which various adult
structures, such as legs and possibly wings,
become apparent for the first time. The
pupal stage is transitional between the larva
and the adult that emerges during the final
molt. In insects in general, the adult stage
is specialized for reproduction and dispersal,
but with ants only some adult individuals are
capable of reproduction (queens and males),
the remainder are a sterile worker caste. In
all hymenopteran societies, all socially
functional individuals are genetically
female, with males serving only to in-
seminate females on mating flights.
The social unit of fire ants is the colony,
and colonies, like individuals, pass through a
characteristic life cycle with phases analo-
gous to birth, growth, reproduction, and
death. Fire ants are very typical of ants in
general with regard to their life cycle.
Briefly, it is as follows. In addition to
workers and a queen, mature colonies con-
tain winged males and females capable of
16
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17
flight and reproduction. These are termed
variously the alates, sexuals, OP reproduc-
tives. On a warm day following a rainy day,
the workers open holes in the nest through
which the alates exit on the mating flight.
Mating takes place 300 to 800 feet in the
air. Mated females descend to the ground,
break off their wings and proceed to search
for a place to dig the founding nest. In this
founding nest, a vertical tunnel 2 to 5 inches
deep, they seal themselves in order to rear
their first brood of workers. They do this
entirely without feeding by utilizing re-
serves stored in their bodies in the form of
fat bodies, wing muscles, and food stored in
the crop. The first worker brood takes
about a month to develop and are the small-
est individuals (minims) in the entire colony
cycle. They open the nest, begin to forage
for food, rear more workers, and care for
the queen. Hereafter, the queen essentially
becomes an egg-laying machine.
The colony grows rapidly by the produc-
tion of workers who gradually enlarge the
original vertical tunnel into multiple pas-
sages and chambers and eventually into the
familiar large mound of spongelike, convolu-
ted passages. Colony maturity is attained
when sexuals are once again produced.
When these sexuals leave on mating flights,
the colony cycle is closed. Mature colonies
of fire ants consist of an average of about
60,000 workers, weighing 70 to 80 grams,
but colonies of up to 150,000 or more have
been reported.
In 1972, Buren recognized that what was
previously considered a single species of fire
ant actually consisted of two species, both
introduced to the USA from South America.
The first was Solenopsis richteri Forel and,
the second was an undescribed species,
which Buren, with characteristic whimsy,
named Solenopsis invicta Buren. This sec-
ond ant is greatly predominant and has been
given the unfortunate common name of the
red imported fire ant. Logic would require
that, in its homeland in Brazil, this ant
would have to be called the "exported fire
ant." I suggest that we not defeat Linnaeus
and his wonderful Latin binomial system.
Let us call it simply the fire ant, S. invicta.
Solenopsis invicta is at home in an ex-
tensive, seasonally flooded plain forming the
headwaters of two rivers in southern Brazil,
an area called the Pantanal. Solenopsis
richteri is at home in Uruguay, parts of
Argentina, and Brazil (Fig. 1). Both were
introduced to the United States by unknown
means at Mobile, Alabama. Solenopsis
richteri was first recorded in 1918 and
spread slowly northward into Mississippi and
Alabama. Sometime between 1933 and
1945, perhaps around 1940, S. invicta ap-
peared in the Mobile harbor area and
proceeded to spread more rapidly, displacing
S. richteri from most of its range. Spread
of both species was both by natural mating
flights and man-aided through the transport
of nursery stock. Thus, by 1953, the range
of the fire ants (remember the two species
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18
Homeland Areas of Fire Ants
-r
i. m ».,. o
82:113-124).
ss
-------
19
were not yet distinguished in these early
reports) consisted of a continuous area from
the Gulf coast to central Alabama and Mis-
sissippi and a large number of incipient
populations associated with nurseries
throughout the Southeast (Fig. 2). Appear-
ance of such incipient populations ceased
after the fire ant quarantine of 1956 was
imposed. By the mid-70's, these incipient
populations had coalesced, and the fire ants
occupied most of the warmer parts of the
Southeast as far west as Texas and as far
south as Corpus Christi (Fig. 3). Most of
this range is that of S. invicta, S. richteri
being presently restricted to parts of
northern Mississippi and Alabama.
There has been much speculation on fu-
ture spread and the ultimate range of fire
ants. Climate is one of the primary limiting
factors to the ranges of many insect spe-
cies, and the study of Pimm and Bartell
(1980) is interesting from this point of view.
These authors studied the climatic charac-
teristics of the areas into which the fire
ant, S. invicta, spread between 1965 and
1976. They created composite climatic va-
riables describing a region's temperature
(Factor 1) and wetness (Factor 2). From
Fig. 4, it can be seen that during this period
the fire ant spread mainly into climatic
zones that were warmer and drier, mostly in
Texas. There was some small spread into
warmer, wetter regions, implying that
. northward spread has reached its limit. Fi-
nally, there is no occupation at all of re-
gions that are cold and dry.
There is other evidence that the nor-
thern range limit has been reached. Morrill
(1977) reports great winter kill of fire ant
colonies in piedmont Georgia during the
winter of 1976-77. Colonies in unprotected
locations suffered 94% mortality in pied-
mont Georgia, while comparable colonies in
southern Georgia showed only 20% mortali-
ty. Clearly, winter harshness must be more
and more limiting to fire ant populations as
they proceed northward. The period for
successful colony establishment also be-
comes shorter as one proceeds north, fur-
ther limiting northward spread. All evi-
dence thus indicates that S. invicta will not
spread significantly further north.
On the other hand, some continued west-
ward spread seems to be occurring, but its
limits are not yet clear. Pimm and Bartell
suggest that parts of Texas will eventually
be occupied but that the ant will not pro-
ceed north of the 0°F isoline. A number of
people have suggested that the ant could
spread all the way across the Southwest to
California and the West Coast, but these
judgements are based almost exclusively on
temperature and sometimes the total rain-
fall characteristics of these areas. An as
yet undiscussed factor is the necessity of
summer rains for fire ant reproduction.
Mating flights normally occur only on warm
days after rain, the rain being necessary not
only to trigger mating flights but to ensure
successful excavation of the founding nest
-------
,5s*-"
Fig. 2. The range of S. invicta and S. rich-
teri in the USA in 1953. The two
species were not yet distinguished
at this time. The broken circles
represent secondary populations,
mostly centered at and limited to
commercial nurseries (from Wilson,
E. O., and W. L. Brown. 1958. Evo-
lution 12:211-218).
Fig. 3.
The ranges of S. invicta
and S. richteri in the
USA in 1974. Solenopsis
richteri is represented
by the darker shading
(from Buren et al. 1974.
J. N.Y. Entomol. Soc.
82:113-124).
1965 IKWitionil
1966
1968
1970
I97J
i'i/.t
I97C
1978
S
u
Distribution of Imported Fire Ants
FACTOR 2 Fig. 4. The "climate space" occupied by S.
invicta in 1965 (cross-hatched) and
1976 (shaded). Factor 1 is a com-
posite climatic variable
representing temperature, and
Factor 2 wetness. The numbers
represent counties in Texas into
which the ant will probably spread
(from Pimm, S. L., and D. P.
Bartell). 1980. Environ. Entomol.
9:653-659).
20
-------
21
and survival through the founding period.
No study has yet considered the timing of
rain as a possible range-limiting factor.
How frequent must warm rain be for main-
tenance and spread of populations? Can the
fire ant reproduce in regions such as Cali-
fornia that get almost exclusively cold win-
ter rains, followed by rainless summers? A
careful study of such factors will probably
show that the potential range of S. invicta
is considerably less than many have suggest-
ed.
All studies of future range have dwelt
almost exclusively on abiotic factors. Bi-
otic factors limiting spread are almost to-
tally arcane. As the ant spreads toward
subtropical Texas and Mexico, it encounters
an ever richer ant fauna, possibly containing
components with habits similar to its own.
How will such interactions with other ants,
or for that matter, any other biotic commu-
nity, influence its success in these regions?
There are essentially no data.
Overall then, we can summarize range
information by concluding that the ant has
reached its nothern range-limit and is still
spreading westward. The ultimate western
and southern range-limits cannot yet be
predicted because we lack so much biotic
and abiotic information.
ECOLOGICAL NATURE
Let us turn now to the ecological nature
of S. invicta. 1 want to develop the case
here that S. invicta, ecologically speaking,
is a weed species, and as such, shows many
of the biological properties of weeds in
general. Weeds are animal or plant species
that are adapted for the opportunistic ex-
ploitation of ecologically disturbed habitats.
Naturally, these are created by flood, fire,
and storm, and consist of new sandbanks,
slumps and landslides, burns, and windfalls.
Man however, creates vast stretches of such
disturbed habitat by clearing forests for
agriculture, domestic, and other uses. The
plant and animal communities that occupy
such disturbed habitats are called early
secondary or early succession communities,
because, left alone, all such areas will
gradually revert to the dominant climax
communities, mostly deciduous forest in the
Southeast. Because such early succession
communities are ephemeral, and because
they are, to a large degree, underexploited
and understocked, the weed species utilizing
these habitats are adapted for very rapid,
scramble-type of exploitation with an em-
phasis on high reproductive rates and effi-
cient dispersal rather than competition with
other members of the community.
Let me discuss each of the weed-like
properties of the fire ant in turn. First, the
fire ant is clearly and dramatically associa-
ted with ecologically disturbed habitat,
most of it created by man. Thus, S. invicta
is abundant in old fields, pastures, lawns,
roadsides, and any other open, sunny habi-
tat. It shares these habitats with many
other weedy plant and animal species, from
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22
human crops to lawn and pasture grasses,
goldenrods, and dog-fennel. Humans are the
fire ant's greatest friend, even though the
sentiment may not be returned.
On the other hand, the fire ant is absent
or rare in late succession or climax commu-
nities such as mature deciduous or pine
forest. When it is found in these communi-
ties, it is usually associated with local dis-
turbance such as windfalls and roads.
Although the fire ant's need for open sun
has often been suggested as the primary
cause of this pattern of occurrence, in reali-
ty this is only one of many correlated fac-
tors, and we must admit to having almost no
hard knowledge of the biotic and abiotic
causes of its distribution. Suffice it to say,
S. invicta, like other weeds, is associated
with open, disturbed habitats.
A second weedy property is the high
reproductive rate that has evolved in re-
sponse to the spotty, rather unpredictable
and ephemeral availability of suitable habi-
tat (in the absence of man-made disturb-
ance). Success in such a situation goes to
the animals and plants that "git thar the
fustest with the mostest," with little atten-
tion paid to competition within the commu-
nity. Fire ants, like other weeds, achieve a
high reproductive rate in part by very high
investment of resources in reproductives.
From the meager data available, I estimate
that S. invicta allocates 30 to 40% of its
annual production in sexuals. This is quite
similar to the allocation to seeds found in
weedy species of goldenrod, and much high-
er than non-weedy goldenrods adapted for
competition in late-succession communities
(Fig. 5). Thus, the average fire ant colony
in north Florida produces about 4,500 sex-
uals per year. Although very little informa-
tion is available for comparison, this seems
quite on the high side for ants in general and
is almost certainly an adaptation to its
weedy habits.
0.5^
0.44 -
0.36 -
L«
O
« 0.28
o
>
1 0.20
g
I °-16
0.08
0
S. nemoralis
S. speciosai
/'^l N\ /S. speciosa
,'/ P\ r
S. canadensis
S. nigosa
S. rugosa
0.5 0 0.5 1.0 1.5
log dry weight of aerial tissue (g)
Fig. 5. Reproductive effort (proportion of
production invested in seeds or sex-
uals) in relation to size of organism
for goldenrods and fire ants (large
black circle). Each enclosed area is
represented by the individuals of a
single population on a dry site (en-
closed in dotted curve), a wet site
(with horizontal shading), or a hard-
wood site (vertical shading) (modi-
fied from Ito, Y. 1980. Compara-
tive Ecology, Cambridge Univ.
Press).
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23
A third weedy property is effectiveness
of dispersal and colonization. In the ab-
sence of man-made disturbance, secondary
habitat is scattered and unpredictable. Its
exploitation depends on the ability to
scatter propagules (sexuals or seeds) over
wide areas on the chance that a few will
find their way to an appropriate site and
colonize it. The fire ant achieves this end
by producing a large number of dispersing
sexuals, as already mentioned. The sexuals
are released from the colonies to take part
in high-altitude, dispersive mating flights
occurring throughout a large portion of the
year (Fig. 6). The queens often fly or are
wind-carried 1/4 to 1/2 mile or more before
settling to the ground, although most settle
at shorter distances. Although data are
mostly unavailable, my impression is that
the newly mated queens settle preferential-
ly in disturbed, partly vegetated habitats,
effectively colonizing them.
The ecological disturbance on which fire
ants depend may not need to be gross, but
can be rather a specific disturbance of the
ant community only. This phenomenon was
first observed by Summerlin, Hung and Vin-
son (1977), who treated with mirex an ant
community in which S. invicta was a minor
component. The mirex killed almost all of
the ground-nesting ants, but after recoloni-
zation, S. invicta and another weedy spe-
cies, Cononryrma tnsana, had greatly
increased dominance over all species (Fig.
7). Many of the native species did not
reappear in the course of this study. Be-
cause the fire ant has such a great advan-
tage over other ants in colonizing, removal
of the native ants resulted in a community
consisting mostly of fire ants and another
weedy ant species.
These results were recently experimen-
tally confirmed by Buren and Stimac (per-
sonal communication), who treated one set
of plots with mirex, one with Amdro and
left one untreated as a control. Plots
treated with either insecticide showed a
reduction in all ant species, but were recol-
onized to much higher levels and greater
dominance by fire ants. Untreated plots
showed either no change or decline in fire
ants. Clearly, the specific ecological stress
or disturbance of the ant community with
insecticide allowed the fire ant to increase
its size and dominance over native ants.
Buren et al. (in press) have provided a
computer-simulation model of how this
takeover might proceed. They reasoned
that there are a limited number of sites
available for ants in a habitat, and these
sites can be occupied by fire ants or other
ants. In a fully stocked habitat, an ant of
any species can appear in an area only if a
site becomes available through death of a
resident colony or appearance of a new site.
The probability that a particular species will
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£
;
;
.
i
Fig. 6. Occurrence and size of
mating flights throughout
the year in N. Florid*
(from NJorrill, W. L. 1974-
Environ. Entomol. 3:265--
271).
Fig. 7. Changes in an ant commu-
nity after treatment with
^. Ten other species
are lumped together. The
two weed species, S. (nvic-
ta and Conomyrma fnsana,
• town separately (from
Summerlin et al. 1977.
ron. Entomol. 6:193-
197).
f \
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SKClO
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-------
succeed in occupying fin available site will
depend upon its relative ability to colonize,
an ability in which we know the fire ant
holds a many-fold advantage over most na-
tive ants because of the large number of
sexuals it produces. Because colonization
by any species depends on the availability of
sites, the rate at which sites become avail-
able, in combination with the colonizing
advantage of the fire ant, will determine
the rate at which the fire ant will increase
its dominance in an area. Whether the sites
are made available by natural colony mor-
tality or by insecticide treatment is imma-
terial. Buren et al. showed that imposition
of 95% annual mortality through insecticide
treatment would cause a population consist-
ing of 1% fire ants and 99% other ants to
convert to one consisting of 99% fire ants
and 1% other ants in only four or five years.
Lower annual mortality rates lead to an
exponential increase in the time it takes
fire ants to reach the same level of domi-
nance. Thus, simple as this model is, it
explains the basic experimental findings of
Buren and Stimac, and is supported by much
biological information on fire ants.
The implications of these studies are
clear: Large-scale, unspecific control pro-
grams such as those utilizing mirex or
Amdro actually aid rather than hinder the
establishment and spread of the fire ant and
accentuate its dominance over native ants.
The reversal of this dominance appears to
be very slow and is poorly understood at
present. Clearly, the relationship of the
fire ant to other native ants in its communi-
ty is an area of utmost importance about
which we know very little. No program to
manage fire ants can hope to succeed with-
out such knowledge.
The fourth and fifth weedy properties of
S. invicta are rapid growth and early repro-
duction. Fire ants achieve rapid growth by
an emphasis on cooperation rather than
competition during the founding and incipi-
ent colony period. Thus, a number of newly
mated queens may share excavation of the
founding nest and rearing of the first brood
of minims. This cooperation, called pleome-
trosis, increases the chances of surviving
the founding period and results in incipient
colonies with about three times as many
minim workers as colonies founded by a
single queen (haplometrosis). Because of
the nature of exponential growth, this initial
boost is maintained throughout the early
growth period, so that after 1/3 of a year,
pleometrotically founded colonies are still
three times as large as haplometrotic ones
(Fig. 8), a clear advantage in competition
and survival of winter or drought.
Once past the incipient period, colony
growth is rapid, requiring about three years
to reach upper colony size limits, and repro-
duction is early (Fig. 9). At the end of two
-------
1000,
g 100 ^
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o
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10
19 OUEENJ ( «>BI
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-------
27
desperately needs attention.
An interesting aspect of fire ant colonies
as they grow is that they change from being
rather poor competitors, in fact from co-
operators, to being rather good competitors.
The most obvious aspect of this change is
that colonies become territorial as they
grow. That is, they defend a plot of ground
against all other fire ant colonies, and pos-
sibly to some unknown extent against some
other ant species as well. The size of these
colony territories is proportional to the
number of workers in the colony, and a
consequence of territorial behavior is that
fire ant populations reach an upper limit
determined by the territory size of mature
colonies. A typical figure for pasture land
seems to be about 20 to 25 colonies per
acre. Establishment of new fire ant colo-
nies within territories occupied by mature
colonies is probably impossible, for the resi-
dent workers kill newly mated queens that
land in their territory.
A final, brief point concerning the ecolo-
gical nature of the fire ant is its seasonali-
ty. Solenopsis invicta is a tropical ant
lacking a true hibernation, yet it shows
strong seasonal!ty in many aspects of colony
life. Most evidence indicates that this sea-
sonality is probably imposed upon a basically
unseasonal life cycle by seasonal fluctua-
tions in temperature and, to some degree,
rainfall. The influence of temperature on
ecology and life cycle may be one more
underappreciated factor in fire ant biology.
We are accustomed to thinking of the ef-
fects of temperature on the rates of various
processes, but there are ample hints for fire
ants that temperature effects are often in
the nature of thresholds or triggers. Ex-
amples of processes whose occurrence as
well as rate is controlled by temperature
would be worker brood production, alate
brood production, mating flights, and suc-
cessful colony founding. Such knowledge is
of obvious importance to our understanding
of the potential and realized ecological
range of the fire ant.
Summing up the ecological nature of S.
invicta, we conclude that it is an opportun-
istic, weed species depending on ecological
disturbance for its continued existence and
success.
COLONY FUNCTION
By colony function, I mean simply the
general internal workings and social rela-
tionships within the colony, including beha-
vioral, physiological, and morphological as-
pects. A useful organizing principle for my
remarks is to consider colony life from the
point of view of production. Organisms (and
colonies) carry out the production of new
biomass in such a way as to maximize
reproductive success, this being merely a
restatement of the principles of natural
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28
selection. Production of any kind requires
some degree of control, as any factory own-
er knows, so let us look at colony function
from the points of view of production and
its control.
By production, I mean the obtainment of
raw material in the form of food, water, and
air and their conversion into new biomass.
There are two primary localities for the
production of new biomass in the colony: (1)
the queen produces new biomass in the form
of eggs. A queen in a large colony is
capable of producing her own weight in eggs
every 24 hours or less. (2) The larvae
produce new biomass as they grow to be-
come new individuals, either workers or
sexuals. Under some conditions, colonies
are capable of tripling their biomass (mainly
workers) in a month.
Under the heading of control, I would
place a variety of behavioral and physiologi-
cal phenomena, many of which have re-
ceived substantial research attention. As
related to production, control deals with
problems of the routing of materials (where
does it go, and when?), rates of production
(how fast?), and allocation of resources,
including labor (how much to each subcom-
ponent?).
A partial list of control mechanisms
would include: (1) pheromones (chemical sig-
nals); (2) various behavioral interactions; (3)
trophic relations (food flow and use); and (4)
therm ©regulation. This list is not complete,
but will suffice for this general discussion.
Pheromones have received a good deal of
attention and a number of effects have been
attributed to pheromonal action. Because
the queen is the only reproductive individual
in the colony, there is widespread belief
that she must also be the center of much of
colony coordination. At least three biologi-
cal characteristics of queens have been at-
tributed to pheromones presumably secreted
by her. The first and most obvious queen
attribute is her attractiveness to her work-
ers. In a normal colony, the queen is always
mobbed by a dense retinue of workers who
cluster around her, groom her, feed her, and
whisk away any eggs she may lay. A number
of workers (human) have shown that the
attractiveness of the queen appears to be
the result of a pheromone secreted by her
and extractable from her body. More re-
cently, Vandermeer and others (1980) have
shown that the contents of the queen's poi-
son sac are similarly attractive to workers,
and it is possible, though not yet certain,
that this is the same attractant described by
earlier workers.
A second and third attribute of the
queen is that her presence prevents winged
female sexuals (alates) from breaking off
their wings (de-alation) and undergoing ova-
rian development. Fletcher and Blum (1981)
have recently presented evidence that both
-------
29
of these effects are caused by pheromones
produced by the queen. Whether all three of
these effects are caused by a single chemi-
cal compound or by several is, at present,
unknown. If the fire ant parallels the
honeybee, there are probably several phero-
mones with complex actions and interac-
tions, and the unraveling of this chemical
annd biological Gordian knot will occupy
years to come.
A number of other pheromones also aid
in colony control. Let me list them briefly,
pointing out that many additional phero-
mones probably still await discovery. (1)
Larvae and pupae are coated with a surface
pheromone that causes workers to recognize
them and presumably to respond appropri-
ately to them by feeding them, grooming
them, and transporting them to favorable
locations within the nest. This chemical
signal acts only upon contact, and its nature
is not yet known. (2) Workers recognize
dead ants by chemical signals that the latter
emit, and respond by removing the dead
from the nest. While this case stretches the
definition of pheromones somewhat, the
death signals are, at least in part, chemical
and appear within an hour of death. (3) I
have mentioned the territorial nature of fire
ant colonies. Although little hard evidence
has ever been advanced, it has long been
believed that recognition of colony member-
ship is mediated by a characteristic colony
odor shared by all members of a colony and
different from that of members of other
colonies. (4) Recruitment of food and new
nest-sites is mediated by a trail-pheromone
produced in the Dufour's gland in the gaster
of workers. In the early sixties, Wilson
(1962) showed that a fire ant forager return-
ing from a food find applies a pheromonal
trail to the substrate using the sting. Nest-
mates follow this trail outward to find the
food, and may in their turn reinforce the
trail upon their own return to the nest.
Each worker's contribution is both attrac-
tive and ephemeral, lasting perhaps 20 min-
utes or so, so that the relative rates of trail
reinforcement and loss determine the level
of pheromone in the trail, and this in turn
determines how many workers are recruited
to the food. This chemical recruitment
system regulates the mass response of the
colony to the food (or nest-site) and is
capable of quite fine adjustments to varying
quantity, quality and distance of food.
While on the subject of recruitment and
foraging, I should mention that fire ant
foragers do not generally sally forth directly
from the nest. Rather, the entire territory
is underlain by an anastamosing system of
underground foraging tunnels. Recruitment
probably actually takes place from the exits
of these foraging tunnels throughout the
foraging territory.
Behaviorally and morphologically, colony
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30
function is dominated by an intricate divi-
sion of labor based upon caste (queen or
worker) and worker size and age. The basic
division of labor, as in all social insects, is
that of reproduction—the queen lays all the
eggs and the workers do all the work. With-
in the worker caste, however, labor is fur-
ther subdivided on the basis of worker size
and age (Fig. 10). In a mature colony,
workers range in size such that the largest
weigh about 10 times as much as the small-
est. Colonies begin life with only small
workers but as they grow, the proportion
and size of larger workers gradually increas-
es, and there is no indication that this trend
ever stops. This phenonemon adds a develop-
mental-time dimension to any discussion of
division of labor by size that has heretofore
not been recognized. In any case, several
general differences in behavior are apparent
between large and small workers—large
workers carry and handle larger particles
and brood, they are more likely to cut up
insect prey, less likely to feed on liquid
food, and less likely to function in brood and
queen care.
Large workers live much longer than do
small workers, but all workers pass through
a series of changes in the labor they carry
out as they grow older. These age-related
changes are superimposed upon and modified
by the division of labor by size already
discussed. Early in their adult lives, work-
Fig. 10. Division of labor by worker size
and age in S. invicta. Top: Sixe-
frequency distribution of worker
size in colonies during growth and
maturity (after Wood and Tschinkel
1981. Insectes Soc. 28:117-128).
Middle: Age, size, task, and loca-
tion in nest. Age on vertical axis,
size (head width) on horizontal axis
(data from Miranda, J., and S. B.
Vinson 1981. Anim. Behaviour 29:
410-420). Bottom: Size of particle
carried by worker in relation to
worker size. Note log scale (data
from Wilson, E. O. 1978. J. Kan-
sas Entom. Soc. 51:615-636).
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31
ers act as nurses, taking care of the queen
and brood, and are thus found mostly in the
brood area. Small workers spend a larger
proportion of their lives as nurses than do
large workers, the largest essentially not
functioning as nurses. As the workers age,
they leave the brood area and move to the
peripheral nest areas to take up their roles
as reserves, for want of a better name. As
such, they receive food from foragers re-
turning to the nest, transfer it to the nurses,
and take part in the many other nest func-
tions such as construction, sanitation, de-
fense, and others. During this period, large
workers are more likely to store liquid food
in their crops for longer periods than are
small workers. Only during the last 25 to
40% of their lives do workers ever leave the
nest to forage. During this final period,
small workers are more likely to forage on
liquids and larger workers on solids and
insects.
It should be noted that none of these
behavioral differences with age and size are
sharp, and that there appears to be a good
deal of flexibility of roles built into the
system. We should also not forget that
these patterns have been worked out for
small colonies, and that there may be both
quantitative and qualitative changes in them
as the colony grows and ages.
Let's turn now to the flow of the food
throughout the colony, the so-called trophic
relationships. Most of the fire ant's natural
diet is insects and other small invertebrates,
although carrion, honeydew, and some plant
material are also taken. Only about 10 to
20% of the colony acts as foragers at any
given time, so that the food they collect
must be shared with the other 80 to 90% of
the colony. Workers themselves utilize only
a small proportion of the colony's food, and
what they do utilize is primarily carbohy-
drates and sugars. The bulk of utilization is
by the two most important producers in the
colony, the queen and the larvae, both of
which get the lion's share of the protein as
well. Once foragers have brought the food
back to the nest, it enters a subtle complex
web of exchanges, conversions, and process-
es (Fig. 11), that we are finally beginning to
unravel, thanks to the work of such
researchers as Howard, Sorenson, and
others. Foragers pass the food to a group of
younger workers called reserves, who in turn
transport it from the nest periphery to the
brood and queen area where they share it
with the nurse workers. Nurses are the
youngest class of workers, who carry out the
functions of brood and queen care and hence
are usually found in the brood area. Nurses
probably convert some of the food to gland-
ular secretions, and they pass both these and
liquid food to the second and third stage
larvae and to the queen, all of whom subsist
entirely on a liquid diet. Solid food is
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32
IARVU I
LARVAE II, III
FOOD
Fig. 11. Trophic relationships within col-
onies of S. invicta. Arrows indi-
cate the direction of food flow.
passed to the fourth stage larvae, who pro-
cess it, utilize part, and probably pass some
of it back to the workers in partly digested
form. They may also pass back glandular
secretions of an unknown nature as well as
excreted material. The queen may also pass
back excreted or secreted material, but she
obviously produces eggs from what she eats.
Many of the eggs hatch, which is what eggs
should do, but there is evidence that some
may be eaten by the newly hatched, first-
stage larvae, an added complexity in trophic
relations. We have recently found that
larvae are needed for continued egg-laying
by the queen.
The image that is emerging with respect
to the flow and use of food is that the
various members of the colony are all pieces
of a whole metabolic system where each
plays a distinct metabolic behavioral role
and all are interdependent. As yet, we have
only a dim idea of how this metabolic labor
is subdivided and specialized among colony
members, but we know enough to see the
beauty and sophistication of it.
IMPORTANT UNANSWERED QUESTIONS
There are many important unanswered
questions concerning the biology of S. in-
victa, and their discussion could occupy
whole conferences. Let me deal with a
sampling of some questions I feel are impor-
tant or interesting.
I. Certainly one of the largest holes in
the fabric of our knowledge of fire ants is in
the area of the population dynamics of colo-
nies. In Fig. 12, I present a hypothetical
survivorship curve based upon my impres-
sions and very sketchy data. The curve
incorporates the following characteristics:
(a) very high mortality during the mating
flight and colony founding period, with per-
haps as little as 0.1% survival; (b) reduced
but still substantial and steady colony mor-
tality during the growth phase; and (c) rela-
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33
I-
I
(WINS FLIDIT MO CLAUSTOAL KK|OI
1016 CO OKIES, WHY «tmmOII
. (MURE COLOtlM
OUP comics
TVm« -»
Fig. 12. Hypothetical survivorship curve for
colonies of S. invicta. Note that
the proportion surviving is on a log
scale.
lively low mortality during the colony matu-
rity stage. We have absolutely no idea of
what happens to colonies when they get old,
so I have entered this phase as a dotted line.
Is there increased mortality during this peri-
od? While this survivorship curve may turn
out to be more or less correct in its out-
lines, we have no quantitative data on age-
specific mortality during any of the life
cycle phases. This kind of "life-table" infor-
mation is absolutely necessary for an ecolo-
gical understanding of the fire ant, let alone
a management program. Ultimately, if we
are to manage it intelligently, we will need
this kind of information for each of the
different environments that the fire ant
occupies.
II. The relationship to native ants has
already been mentioned. Although an ex-
otic, the fire ant is a member of a biological
community, relating in some manner to
other members of that community. I have
already provided compelling evidence that
its relation to other ants is a key component
in our understanding of fire ant ecology, yet
only scattered, generally unquantitative in-
formation is available.
HI. While we know generally what fire
ants eat, we have only poor quantitative
knowledge of the impact of their feeding on
the community in which they live. Further-
more, individual colonies show idiosyncratic
food preferences whose meaning and origin
we do not understand. Surely, this is an
important aspect of any bait-based fire ant
control method.
IV. The process of colonization of avail-
able habitat is poorly understood. How
much control do queens exercise over the
sites in which they settle after a mating
flight? How are these sites selected?
Which site and other physical characteris-
tics influence success of colony foundation
and how much? The founding period is
obviously one of the most vulnerable stages
of colony life, so that, from the manage-
ment point of view, knowledge of this period
seems imperative.
V. The number of mated queens during
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34
various parts of the life cycle is emerging as
an important question. I have mentioned
that colonies are often founded by groups of
mated queens in cooperation, and we have
some dim idea of what might be the advan-
tages of such behavior, though none are as
yet quantitatively characterized. We know
that, during the post-founding period, the
workers kill all but one queen, so that the
colony enters the growth phase with a single
queen. It is therefore interesting that ma-
ture colonies often have more than one
inseminated queen, capable, under the right
conditions, of laying eggs. In most of the
fire ant's range, these extra queens are
inhibited from laying eggs, but can take the
place of the colony queen-mother if she is
lost or dies. In some of the western parts of
its range, all of the mated queens in a
colony may lay eggs (polygyny), and a colony
may contain hundreds or even thousands of
laying queens. What brought about this
profound change, and why? What is the
effect of queen number during various parts
of the colony cycle on the ant's ecology, and
possibly on its potential range? What is the
source of these multiple mated queens? Are
they adopted after mating flights? If so,
why are they not killed? Does mating take
place in the nest? If so, what is the genetic
importance, and what effect does it have on
the westward spread? If mating flights are
unnecessary in polygynous colonies, can the
ant survive in areas where there is no sum-
mer rain, such as California?
VI. Finally, the fact that, in comparison
with those of Brazil, the fire ants in the
USA are all much more closely related to
one another because they are descended
from a single pair or small number of indi-
viduals has received practically no atten-
tion. According to kinship selection theory
and plain com mon sense, this situation could
bring about major differences between the
biology of the fire ant in the USA and its
biology in Brazil. For example, it might
affect the degree of cooperation and thus
success during the founding period, it might
affect the degree of colony distinctness and
competition, and it might even affect the
mode of reproduction.
SUMMARY AND FINAL REMARKS
In closing, the fire ant is a weed species
whose continued existence is favored by
human ecological meddling. Its success as a
weed is based on high reproductive rate,
excellent dispersal and colonizing ability,
rapid colony growth, and early reproduction.
What we do not know about its ecology can
indeed hurt us, as is becoming clear with
respect to large-scale, insecticide-based
control programs. Colony life is dominated
by a complex and subtle division of labor
and an intricate set of trophic relationships.
These and various behavioral control mech-
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35
anisms regulate colony function to maxi-
mize reproductive success.
Seen from the biologist's point of view,
without the rancor and heat characteristic
of the political arena, the fire ant repre-
sents a wonderful research opportunity al-
most unique in the history of myremecology.
The ant's abundance, ease of maintenance,
and general habits make it an outstanding
subject for research, while our society's
relatively high need for knowledge of this
ant gives us the opportunity to carry out
this research. This potential knowledge may
some day more than repay us for the real
and imagined damage and aggravation the
fire ant caused along the way.
Whatever we, as a society, decide to do
about the fire ant, whether it be to fool
with it or leave it alone, we are obligated to
do it intelligently, with a sound foundation
of biological knowledge. If the decision is
to "do something" about the fire ant, even if
only in certain situations, we must know a
great deal more of the fire ant's secrets
before we can ever hope for success.
Fletcher, D. J. C., and M. S. Blum. 1981.
Pheromonal control of de-alation and
oogenesis in virgin queen fire ants.
Science 212:73-75.
Morrill, W. L. 1977. Overwinter survival of
the red imported fire ant in central
Georgia. Environ. Entomol. 6:50-52.
Pimm, S. L., and D. P. Bartell. 1980. Sta-
tistical model for predicting range ex-
pansion of the red imported fire ant,
SoZenopsis invicta, in Texas. Environ.
Entomol. 9:653-658.
Summerlin, J. W., A. C. F. Hung, and S. B.
Vinson. 1977. Residues in non-target
ants, species simplification and recovery
of populations following aerial applica-
tions of mirex. Environ. Entomol.
6:193-197.
Vandermeer, R. K., B. M. Glancey, C. S.
Lofgren, A. Glover, J. H. Tumlinson, and
J. Rocca. 1980. The poison sac of the
red imported fire ant, Solenopsis invicta,
queens: source of a pheromone attract-
ant. Ann. Entomol. Soc. Amer. 73:609-
612.
Wilson, E. O. 1962. Chemical communi-
cation among workers of the fire ant,
Solenopsis saevissima (Fr. Smith). I.
Organization of mass-foraging. Anim.
Behaviour 10:134-149.
REFERENCES
Buren, W. F. 1972. Revisionary studies on
the taxonomy of the imported fire ants.
J. Ga. Entomol. Soc. 7:1-27.
Buren, W. F., J. L. Stimac, and F. G. Max-
well. 1982. A model of imported fire ant
populations: implications for a difficult
problem. Science : .
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THE STATE PERSPECTIVE OF THE IMPORTED FIRE ANT
Reagan V. Brown
Commissioner
Texas Department of Agriculture
For many years, the imported fire ant
was considered a rural problem. It repre-
sented a headache for the farmer, rancher,
and rural landowner, but was of little con-
cern to urban residents, and therefore to
urban legislators.
Today, the situation has changed dra-
matically. No longer are our urban parks
and playgrounds free from this damaging
and dangerous pest. The appearance of fire
ant mounds on football fields, in city parks,
and on urban lawns has brought into sharp
focus the fact that the fire ant is a concern
of all citizens.
The imported fire ant now totally infests
several southern states, and threatens to
overrun several others. Texas, Alabama,
Arkansas, Florida, South Carolina, North
Carolina, Mississippi, Louisiana, and Georgia
all report infestations, and Puerto Rico has
just recently been added to the list. In the
south a total of 230 million acres are infest-
ed. In Texas alone, the fire ant now infests
45 to 50 million acres, and the number
grows each day.
The fire ant is marching like Sherman's
army throughout the South, and it is safe to
say that the threat is no longer of infesta-
tion, but of invasion.
There is a very real need today to ad-
dress the fire ant problem in a calm, ration-
al manner, especially in light of the sensa-
tionalism surrounding the issue. This con-
ference will do a great deal to fulfill this
need. But the fact remains that the fire ant
is one of the most damaging and insidious
pests to come down the pike in a long while.
Consider these facts:
1. Each month, two-and-a-half million
Americans are stung by the imported fire
ant. Some 4,000 of these victims experi-
ence allergic reactions. In Texas, two
deaths have been officially attributed to
fire ant stings. Deaths also have been
reported in Georgia, Florida, Alabama, Mis-
sissippi, and North Carolina.
2. Productive farm and ranch land is
being abandoned because of fire ant in-
festations. Infested counties in Texas aver-
age 80 to 90 mounds per acre. However, we
have seen up to 600 mounds per acre in very
severe cases. From a purely economic
viewpoint, the question must be raised as to
what effect this will have on property val-
ues in both rural and urban areas.
3. While the economic impact on
stockraisers can be fairly easily determined,
an unknown factor at the present time is the
extent of damage to wildlife. Fire ants will
viciously attack new born calves, but they
36
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37
also will kill quail, ground squirrels, young
deer, and even earthworms.
4. So far, the imported fire ant has not
moved into the colder states, nor farther
west than Texas. However, the fire ant is a
notorious "hitchhiker." Every state is vul-
nerable as long as the possibility exists that
the fire ant could accidentally be introduced
through interstate movement of vehicles
and products.
5. Preliminary studies show that fire
ant infestations can definitely decrease
yields in some crops. One study documents
a 5.6 bushel-per-acre decline in soybean
yields in infested fields. Yield damage also
has been seen in corn crops. The spread of
the fire ant into major citrus and vegetable
producing areas of the nation—such as the
Lower Rio Grande Valley of Texas, where
much harvesting is done by hand—could pre-
sent serious danger to workers who harvest
these crops. A point could be reached at
which it would not be possible for workers
to even enter the fields.
6. Definitive economic impact studies
have not been conducted recently. How-
ever, in 1977 it was estimated that the nine
infested southern states suffered crop losses
and pastureland damage of over $50 million.
That amount is certainly greater today.
The magnitude of the fire ant infestation
in the South is alarming. But equally worri-
some is the speed at which this pest has
spread. Texas, one of the most seriously
affected southern states, offers a good ex-
ample. In 1973, 57 of 254 counties in Texas
reported fire ant infestations. By 1975, the
number rose to 71, and by 1977 the total
stood at 91. As of this month, the list
includes 110 Texas counties, some in the
western-most areas of the state. Several
scientists at a recent meeting in Texas
pointed out that control pesticides with long
residual qualities, now banned, are still in
the soil and are helping keep down insect
populations. As these chemicals degrade,
we could see even more rapid growth in
populations of several damaging insects, in-
cluding the fire ant.
The following reports from individual
states give some indication of the scope of
the problem:
From the Alabama Division of Plant In-
dustry: At the present time, only three of
Alabama's 67 counties remain free of the
fire ant. The greatest number of complaints
come from forage farmers, but calls also
are received from nurserymen, homeowners,
school officials, and others.
The Arkansas State Plant Board reports
that population density has increased dra-
matically over the past two or three years
as no control program has been in existence.
Every land acre in the state of Florida is
infested with the imported fire ant, accord-
ing to the director of the Florida Imported
Fire Ant Program. He reports a sharp
increase in the number of fire ant stings
among workers in citrus groves, as well as
damage to young citrus trees caused
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38
by ants girdling the trees.
Increases in fire ant populations on new-
ly-developed apartment, condominium, and
business sections has focused the problem in
many of South Carolina's urban areas, ac-
cording to state entomologists.
North Carolina reports a somewhat less
severe infestation problem than most other
southern states. Because of the limited
problem, state entomologists report that
they are in a position to successfully control
the spread. Officials, however, underscore
the continued need for a control material
that is inexpensive, effective, and can be
applied during most of the spring, summer,
and fall months.
Mississippi reports that the ant is rapidly
moving into northern portions of the state
that formerly were fire ant free. State
officials report serious problems caused by
the fire ant undermining levees used for
flood control. In addition, the number of
pine seedlings destroyed by the ant is
increasing.
In Louisiana, it has become necessary to
cancel recesses at some schools due to fire
ant infestations on playgrounds. Pest con-
trol officials report that since June of 1978,
population density of the imported fire ant
has increased by 75 percent.
Officials of the Georgia Department of
Agriculture indicate that the fire ant, after
being eradicated from much of the state
with mirex, reappeared after the chemical
was restricted, and its use banned.
In my own state, the House Select Com-
mittee on Fire Ants said, and I quote, "The
problem has passed the serious level and
reached the critical stage." The situation
was deemed serious enough that the Gover-
nor this spring released an additional
$500,000 in emergency contingency funds to
fight the fire ant, an amount that was
matched by the Texas Department of Agri-
culture's own contingency funds.
As you can see, the magnitude of the
problem facing these southern states is im-
mense. Most officials concede that the
imported fire ant will never be eradicated in
this country, but only controlled. Because
of the threat to human lives and property, I
cannot emphasize strongly enough the need
for a nationwide mobilization to stave off
this invasion. There is virtual across-the-
board agreement that the following steps
must be undertaken if we are to achieve the
control that is so desperately needed:
1. The U.S. Environmental Protection
Agency must make speedier decisions in
granting experimental use permits for new
control chemicals, so that effectiveness and
environmental safety can be more rapidly
determined for promising new control
agents.
2. In many cases, state funding for fire
ant research is nearly as great as federal
funding levels, and we feel this is inequit-
able since the fire ant is a national problem.
We must renew our commitment to discov-
ering new biological controls, as well as
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39
effective, safe chemical controls, and the
federal government must bear a greater
share of the load.
3. U.S. Department of Agriculture fund-
ing for fire ant control currently stands at
$5.9 million, to be divided among nine states
and one commonwealth. This amount could
easily be utilized in Texas alone. Federal
funding levels for fire ant control should be
increased and maintained until effective
control is achieved.
4. Two weeks ago, the Southern Legisla-
tive Conference of State Legislators ap-
proved a resolution urging each member to
support the allocation of state funds for
imported fire ant research and control. The
resolution also supported several of the
needed steps that I detailed previously. This
action should serve as a model for
legislators at the national level.
5. Perhaps most important, we must
reach a national consensus among all con-
cerned on how to best achieve the goal of
fire ant control. This includes environmen-
tal groups, researchers, government agen-
cies, and all others. Only through co-
operation can this be achieved. Control of
the imported fire ant is in the interest of,
and not contrary to, environmental protec-
tion.
I hope that I have shed some light on the
seriousness of this problem and of the diffi-
culties facing those states that must deal
with it. I feel this summit meeting is a
giant step forward in the process of gaining
the consensus and understanding that I men-
tioned, but it is only the beginning.
The situation damands action. Let us
work together to make this conference a
success and, ultimately, to achieve victory
in the fight against the imported fire ant.
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THE ENVIRONMENTAL PERSPECTIVE OF THE IMPORTED FIRE ANT
Carolyn Carr
Vice President
Gulf Coast Region, Sierra Club
(Report not available at time of symposium completion)
40
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Panel Reports
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PANEL I
SOCIO-ECONOMIC FACTORS RELATING TO THE EPA AND ITS MANAGEMENT
J. Charles Headley, Chairman
University of Missouri
Arnold Aspelin, Reporter, OPP-EPA
Washington, D.C.
C.T. Adams, USDA
Gainesville, Florida
Ted Brooks
Mississippi State University
Ralph E. Brown
Florida Department of Agriculture
Gerald A. Carlson
North Carolina State University
Carolyn Carr, Vice President
Gulf Coast Region of the Sierra Club
Auburn, Alabama
Frank James, M.D.
San Antonio, Texas
Quentin Jenkins
Louisiana State University
John Schaub, NRED-ERS
Washington, D.C.
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INTRODUCTION
It is important to evaluate the socio-
economic aspects of the imported fire ant
(IFA) to assure that the benefits and costs
of alternative actions that could be taken
toward the ant are considered. It is also
important to consider the effects of the ant
on people and their lives such as people's
perception of the pest and the effects it
may have on their health and happiness.
This report evaluates the benefits of
controlling the ant, costs of large scale
treatment programs, and the role of and
need for education, information, and re-
search in support of cost effective manage-
ment of the IF A.
EVALUATION OF BENEFITS AND COSTS
Benefits of IFA Control on Agricultural
Sites
Benefits from IFA treatment vary among
different sites. Generally, the benefits of
control on non-agricultural sites are higher
than on agricultural sites. The data are not
complete enough to support the assertion
that the IFA is truly an economic pest in
terms of agricultural losses. The IFA seems
to be primarily a nuisance and human health
pest rather than a pest that causes signifi-
cant actual losses on large numbers of farms
in the southeastern United States. IFA
control in agriculture, however, can be ben-
eficial in some situations. Areas that might
benefit most from treatment are (1) live-
stock production sites, (2) hay production
land, (3) soybeans, and (4) fruit, vegetable,
and nursery crops. Studies report losses in
hay yields, quality of hay, soybean yields,
and damage to equipment from IFA. Other
studies report livestock losses from IFA
stings.
Studies by Lofgren and Adams (1981)
showed an average decrease of 14.5% in
soybean yields for eight paired fields with
infestation rates of 49 to 176 mounds per
ha. These losses are primarily due to har-
vesting difficulties caused by the ant. Lof-
gren and Adams are continuing these studies
in an attempt to cover more of the infested
area. At present one cannot generalize
from these findings as to the significance of
soybean losses across the infested area in
the southeast U.S.
The IFA also causes discomfort and
health problems to humans conducting agri-
cultural activities. For example, ants tend
to accumulate in hay bales left on the
ground and create problems for workers
cultivating and harvesting fruit and vege-
tables. Nursery workers also have problems.
Additionally, nurseries that have IFA cannot
ship plants to non-infested areas.
- A detailed analysis was made of agricul-
tural benefits and costs of IFA controls for
one county in Florida covering the year
1973. The county has a broad range of agri-
41
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42
cultural and non-agricultural activities
and a well-established IF A infestation. The
analysis, completed as a Master's thesis in
1975 (James D. Wilson), indicated that
treatment of 15,931 acres in Washington
County, Florida, resulted in agricultural
benefits totaling $2,128. Total operational
and administrative costs for mirex treat-
ment in the county were $11,947; for every
dollar of agricultural benefits received,
$5.61 were spent. The agricultural benefit
averaged $0.13 per treated acre compared
to the average treatment cost of $0.75 per
acre for aerial applications. It is not known
the extent to which these results can be
extrapolated to other counties in Florida or
the total nine-state area where the IF A is
an agricultural pest.
In conclusion, given available data on
agricultural losses and treatment costs,
broad-scale control programs are not war-
ranted. However, treatment may be justi-
fied where losses to crops or damage to
machinery occurs and/or where IFA impair
the effectiveness and safety of agricultural
workers.
Health Effects of IFA and Its Control
IFA causes discomfort, a certain amount
of serious reactions and infections, and a
smaller number of deaths due to stings.
Information on the size of the population
and the characteristics of individuals at
greatest risk from IFA is inadequate. To
determine an economic rationale for IFA
control, reliable estimates of the number of
persons at risk due to sensitivity are needed.
The Florida study by Wilson (1975) in-
cluded an analysis of non-agricultural bene-
fits of IFA control. The analysis indicated
that the probability of a household exper-
iencing stings during a year was 0.76. The
probability of a household experiencing
stings and incurring professional medical
costs was 0.048, and the probability of a
household experiencing stings and incurring
home medical costs was 0.734. Professional
medical costs averaged $15.75, whereas
home medical costs averaged $4.36. Anoth-
er study (Triplett 1971) reported an average
cost per person for professional medical
care of $28.50. Wilson projected total home
and professional medical costs in the county
studied to be $9,154, with expected costs of
$0.51 per household for professional medical
care for stings and $2.40 for home medical
care.
By far the most concern for human
health associated with IFA is with hypersen-
sitivity to stings. Rhoades et al. (1977)
recorded allergy systematic reactions as re-
ported to allergists in Jacksonville, Florida.
They found an incidence rate of 3.8 per
100,000 population. Rhoades et al. (1977)
believe that this is a minimal estimate since
patients who went to emergency rooms and
those who were not diagnosed were not
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A3
counted. While the data on health effects,
including secondary infections, is very epi-
sodal, it is clear that the health effects of
the pests cannot be ignored.
Individuals who are allergic to the IF A
toxins may incur considerable medical costs.
These costs may include desensitization pro-
grams and/or hospitalization. There are
also several well-documented cases of
deaths resulting from IF A stings.
Further information on costs and bene-
fits of control are available from large
consumer surveys. In 1980 and 1981, the
American Cyanamid Corporation conducted
two large telephone surveys on the willing-
ness of households to expend resources to
obtain ant-free conditions. Approximately
82% of those who said they "had a fire ant
problem" indicated they would treat the
problem. Seventy-eight percent of those
who would treat would do so with an insecti-
cide. The surveys indicated that about one
million households were treating for IF A
with insecticides in 1981, with the balance
(22%) using gasoline, boiling water, or a
cultural practice. The areas treated by
farmers were: lawns, 73%; gardens, 58%;
pastures, 54%; row crops, 19%; and woods,
4%. The most frequently used insecticides
were chlordane and diazinon. Seventy-five
percent said they would pay at least $7.50
for complete control of up to one acre. The
retail lawn and garden market price of Am-
dro* is $7.00 to $15.00 per pound.
There is considerable concern about pos-
sible short-term and long-term human
health effects from insecticides used to
control the IF A. The short-term problem
centers on poisoning due to direct contact
with the pesticides. In 1975, the EPA
estimated approximately 200 deaths from
pesticides in 1975 (EPA 1976). Work by
Hayes and Vaughn (1977) suggests that about
50 were deaths in which accident could not
be ruled out while the remainder were in-
tentional, i.e., murder or suicide. Data do
not permit estimates of deaths due to
chronic disease induced by pesticides.
The possible long-term problems concern
occupational exposure of some individuals
and the risk to the general population from
widespread use of IF A pesticides. The ma-
jor pesticides (dieldrin, heptachlor, and mir-
ex), formerly used for broadcast or aerial
application in IFA control, have been can-
celled due to possible human health and
environmental risks. The compounds were
found to be carcinogenic or teratogenic.
Little research data are presently avail-
able on possible health effects of the two
pesticides now being considered for IFA
control. Amdro, a new compound, is only
conditionally registered. Ferriamicide,
which is not registered, is a new formulation
of mirex. While little is known about ferri-
amicide, mirex was cancelled because of its
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44
teratogenic and carcinogenic properties and
because of the dangers posed by its degra-
dates, which include kepone and photomirex.
EVALUATION OF ALTERNATIVE LARGE-
SCALE TREATMENTS
The purpose of this section is to identify
possible alternative large-scale IF A treat-
ment programs or scenarios and to consider
their costs and operational feasibilities.
Decisions must be made about chemical
registration for aerial and/or ground broad-
cast application. Also, decisions must be
made on the extent of financial and institu-
tional support for pesticide application pro-
grams, primarily large-scale aerial broad-
cast programs:
Tables 1 through 4 outline four alterna-
tive programs including approximate treat-
ment acreages, treatment costs, and indica-
tions of operational feasibility and limita-
tions. The particulars presented in these
tables should not be taken as projections of
actual outcomes, but rather as indicative of
a possible range of outcomes. Key aspects
in the design of the four sample programs
are as follows:
A. Chemicals assumed to be registered
for use (aerial, ground broadcast, and
mound-to-mound): Amdro and ferriamicide.
B. Level of involvement/support by
state/federal government units: (1) state/-
federal eradication, totally funded and sup-
ported by public funds; (2) federal/state/-
local government support and funding of
aerial suppression program, with cost shar-
ing in line with traditional formulas; (3)
federal/state subsidization of aerial relief
program with landowners paying a signifi-
cant share of treatment costs, e.g., 1/3 (for
Amdro $1.66 of $5.00 per acre of $0.83 of
$2.50 per acre for ferriamicide); and (4) free
market treatment by landowners, where
they incur all chemical and application
costs. Government roles in research and
educational/extension.
Each alternative assumes the availability
of Amdro or ferriamicide for purchase by
landowners in addition to whatever treat-
ment would be provided by the publicly
supported programs.
For the three state/federal alternatives,
the cost per acre of broadcast treatment
o
was estimated as:
Amdro Ferriamicide
Pesticide
Application,
guidance,
overhead
$2.65
$2.35
$5.00
$0.35
$2.15
$2.50
For the non-subsidized relief approach,
costs per treated acre were estimated as:
Amdro Ferriamicide
Pesticide
Application,
guidance,
overhead
$6.00
$1.00
$7.00
$1.25
$1.00
$2.25
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45
Table 5 summarizes the evaluation and
outlines the key aspects of the four ap-
proaches. The eradication and suppression
alternatives are not considered prudent or
advisable, as they would cost more than the
benefits derived. Funds would be better
utilized in other pursuits. The subsidized
relief type program haspotential in line
with the approach now being used in several
states. Subsidy levels could be adjusted to
influence the scope of the program desired
and/or availability of matching funds. The
non-subsidized market approach appears
most feasible and would offer maximum
opportunity to tailor treatment costs to user
benefits.
Before any funds are committed, the
merits of the alternative approaches must
be compared to the other public programs
with claims on federal funds. An evaluation
of the merits of large-scale treatment pro-
grams relative to other non-IFA programs
has not been made. Also, when considering
alternative treatment programs, decision
makers should be cognizant of the possibil-
ity of legal action being brought against the
use of ferriamicide. Since ferriamicide is a
formulation of mirex, environmental organ-
izations will probably challenge any regi-
stration of ferriamicide, even registration
under Section 18, emergency exemptions,
since there may be no documented agricul-
tural emergency.
Data for Estimating Benefits and Costs
The current data are limited in their
usefulness to assess the costs and benefits
of the IFA in agricultural crops, livestock,
property, forestry, human health, recrea-
tion, and wildlife. Consequently, the bene-
fits and costs of various IFA control options
cannot be fully evaluated. The following
information represents the types of data
that should be developed to estimate the
costs and benefits associated with the IFA.
A. Costs
1. Crop production
a) Extent and unit value of direct
losses from IFA feeding by crop
and level of infestation
b) Extent and unit value of crop a-
bandonment as a result of mounds
or incomplete harvesting by crop
and level of infestation
c) Unit value of reduced efficiency
of cultivation and harvesting, by
crop and level of infestation, for
equipment and labor, including
cost of machine damage and re-
pair, time to perform activities,
wage rates, and quality of har-
vested product
2. Livestock production
a) Number and value of death losses
by type of animal and level of
infestation
b) Veterinary costs by type of ani-
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46
mal, frequency of occurrence, and
infestation level
c) Value of reduced rates of gain or
level of milk production by type
of animal, frequency of occur-
rence, and level of infestation
3. Forestry
a) Extent and value of losses by tree
type and level of infestation
b) Extent and cost of replanting by
tree type and level of infestation
c) Increased labor costs of planting
and harvesting by tree type, level
of infestation, and frequency of
occurrence
4. Human health
a) Number of deaths from IF A stings
b) Treatment costs resulting from
IF A stings
c) Days and value of work lost from
IF A stings
d) Proportion of the population with
systemic sensitivity
5. Recreation and wildlife
a) Extent and value of loss of visitor
days by type of recreation and
level of infestation
b) Number and value of death losses
by species of animal and level of
infestation
B. Benefits
1. Extent and value of IF A as a predator
by crop and infestation level: in-
cludes reduced management costs,
decreased insecticide use and appli-
cation costs, and reduced crop losses
2. Impact of IFA on beneficial insect
populations and the resultant ability
of beneficials to control economic
pests by crop and infestation level
3. Extent and value of predation on nui-
sance and injurious pests to humans
and wildlife
Data are also needed to evaluate the
benefits and costs associated with alterna-
tive levels and methods of control programs.
These information needs follow:
A. Information on the current situation:
geographical distribution, sites affected,
intensity of infestation, and effective-
ness of current control practices
B. Identification and description of controls
C. Effectiveness of controls by type and
level of infestation (include resurgence
aspect of IFA)
D. Costs associated with controls:
1. Direct private costs
2. Direct public costs
3. Indirect private and public costs as-
sociated with reduced predation, re-
surgence, human health, and environ-
mental effects
E. Benefits associated with controls:
1. Value of reduction in crop and live-
stock losses
2. Reductions in crop and livestock pro-
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47
duction costs
3. Value of reduction in human health
effects
4. Value of reduction in adverse recrea-
tional and wildlife effects
When plans are developed to collect data
for analytical purposes, consideration must
be given to the quality of the information
required, the length of time available to
collect and analyze the data, and the cost of
these activities. In the case of IFA control
and the role of various governmental units,
there are short and longer term needs. De-
cisions on pesticide registration for IFA
control are short-term, while evaluation of
the control programs is a long-term need.
Economic Effects of IFA Outside Infected
Areas
The IFA is a mobile pest, and some fear
it could spread to areas where conditions
are suitable for establishment. For ex-
ample, the climatic conditions in California
are believed to be compatible with the IFA.
Given the extensive irrigated production of
fruits and vegetables in California, the IFA,
if established, could significantly impact
such labor-intensive crops. Where the dan-
ger of such an agricultural effect is coupled
with the effect the IFA could have on
People as a nuisance and health problem, the
federal government has some responsibility.
The appropriate federal role in this case
would be operating a quarantine and inspec-
tion program to prevent the interstate
spread of IFA.
There appear to be no significant nation-
al effects of the IFA on the price of farm
products. Therefore, consumer expenditures
for food and fiber probably are not influ-
enced by the presence of IFA.
EDUCATION AND EXTENSION ACTIVITIES
Although several agencies and institu-
tions have been involved with IFA informa-
tion, more education is needed. There is (1)
a lack of reliable information on home-
owners' knowledge and perceptions about
IFA control procedures, and (2) considerable
misconception about effectiveness of var-
ious pesticides, human hazards from aerial
applications, and health effects of IFA
stings. If properly compiled and presented,
the current information on the IFA can
decrease the human health and agricultural
problems caused by the IFA.
New residents to IFA-infested areas,
young children, campers, and residents to
newly IFA-infested areas are logical educa-
tion candidates. Local television, news-
paper articles, and "welcome wagon" associ-
ations are useful media. Information on how
to avoid ants, how to control backyard
mounds, and what to do if medical help is
needed should be presented. IFA training
could be given in schools together with
training for other dangerous insects and
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48
plants.
Special care should be directed toward
individuals who are hypersensitive to IF A
stings. Information about various precau-
tionary and medical actions needs to be
made available through school nurses, 4-H
clubs, etc. Consideration should be given to
forming national information networks pre-
dicting likely victims of serious reactions to
IF A stings.
IF A control recommendations in urban
areas for individual homeowners need spe-
cial attention. Methods of control, speed of
action, rates per mound, and hazards of
pesticides need explanation. A regular ex-
tension publication to be used regionally
should be a top priority extension activity.
Radio and television programs for children
and parents of young children are needed.
Automatic telephone messages for IF A in-
formation should be tried, also.
Information on IF A should accompany
IF A bait when it is made available through
state and local programs. The current Flor-
ida information sheet is a good example.
The state departments of agriculture should
attempt to increase IF A information
through their weekly bulletins.
Schools, rights-of-way, parks, and other
public places often are treated. Managers
and users of these facilities should have
special IF A training programs through uni-
versity extension offices. Urban pest con-
trol information from extension seems lim-
ited in many IFA areas. Demonstration
projects in urban areas would be useful.
Others that should help with IFA training
are state park, public health, and military
officials.
As soon as more research is available
concerning seedling damage and soybean
harvest, the agricultural extension service
can expand its IFA control recommendations
to include crop land. This could be done by
soil type, cropping system, and coincidence
with adjacent IFA infestations. Methods to
avoid IFA damages must be included, such
as changing type of hay-handling equipment.
Information directed at farm workers
also is needed. Fruit workers, hay har-
vesters, etc., and their employers can be
shown how to avoid stings. Farmers need
information on the effect of IFA stings on
the availability and productivity of labor.
GENERAL CONCLUSIONS
Federally-supported programs aimed at
eradication or preventing the spread of IFA
have not been successful. The current data
are not complete enough to support general-
izations about the importance of IFA as an
economic pest across the currently-infested,
nine-state region. Therefore, due to uncer-
tainty of success and the widespread eco-
nomic need, a rationale for future large-
scale control programs to eradicate or pre-
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49
vent the spread of IF A cannot be defended.
Funding as well as legal and technical con-
straints work against commitment to such
efforts. A more prudent course would seem
to be to pursue smaller efforts to relieve
the pressure of the pest in localities where
it is most critical. Through the use of
market alternatives, public and private land
managers can decide to apply controls
where benefits appear to justify the costs.
The appropriate role of government,
especially federal, is to conduct research to
provide pest management information, to
operate inspection and quarantine programs,
to attempt to protect areas not already
infested, and to see that public-owned lands
are managed properly with respect to IF A.
RECOMMENDATIONS
Federal funding
1. The imported status of the IF A should
not be considered justification for fur-
ther federal involvement in control or
eradication programs. However, federal
support of and involvement in research
related to IF A should continue.
2. Preventing the spread of the IFA should
not be considered justification for fund-
ing federal control programs. Operating
inspection and quarantine programs to
protect uninfested areas is justified.
3« Treatment costs should be borne by the
direct beneficiaries such as farmers and
property owners.
Data for estimating costs and benefits
1. Immediately begin collecting informa-
tion on damages and benefits of IFA
control, relying principally on the in-
formed judgment of experts in the field.
These experts should draw on available
research information, but rely heavily on
their own field experience. Develop a
structural process for collecting and
evaluating the expert judgments. One
such method is a delphi-type approach.
This should be a joint federal/state acti-
vity.
2. Utilize the data to assess the economic
and social implications of alternative
control options following accepted anal-
ytical procedures.
3. Analyze the strengths and weaknesses of
the data and develop longer term re-
search, data collection, and monitoring
plans to improve the data. Initial atten-
tion should focus on data items that are
most critical and least reliable. A work-
shop could be held to determine and
establish research, survey, and monitor-
ing priorities.
Education, training, and extension
1. Devote new resources to IFA informa-
tion and training activities. This should
be the lead responsibility of the Cooper-
ative Extension Service, U.S.D.A., public
schools, and other agencies.
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50
Research in IF A and its management
1. Research must be done on the percep-
tions of homeowners, farmers, and other
groups as to (1) the IF A as a pest, (2)
pesticides, (3) pesticide hazards, and (4)
willingness to contribute to IFA control.
2. Conduct a detailed epidemiological study
in IFA-infested areas to estimate the
size of the human population at risk
from IFA stings, the frequency of health
effects, and their significance.
3. Better coordinate and target research
efforts on the biology and control meth-
ods of the IFA.
IFA management on federal/state lands
1. Federal/state agencies responsible for
managing lands subject to IFA infest-
ation should develop IFA management
programs that are consistent with eco-
nomic thresholds.
2. Agencies should demonstrate IFA man-
agement practices that can be emulated
by private land managers on similar type
sites.
3. State/federal management demonstra-
tion projects should be coordinated with
research and extension programs.
REFERENCES
Hayes, W.J. and W.K. Vaughn. 1977. Mor-
tality from pesticides in the United
States in 1973 and 1974. Toxicology
Appl. Pharmacology 42:235-252.
Lofgren, C.S. and C.T. Adams. 1981. Re-
duced yield of soybeans in fields infested
with red imported fire ant, Solenopsis
invicta Buren. The Florida Entomolo-
gist. 64:199-202.
Rhoades, R.B. et al. 1977. Hypersensitivity
to the imported fire ant in Florida: A
report of 104 cases. J. Fla. Med. Assoc.
64:247-254.
Triplett, R.F. 1971. Statement: Medical
Significance of the Imported Fire Ant,
and Allied Chemical Corp.: A Health
Impact, in memorandum of Allied Chem-
ical in support of opposition to cancella-
tion of mirex registration.
Environmental Protection Agency. 1976.
National Study of Hospital Admitted
Pesticide Poisonings, Epidemicologic
Studies Programs. Office of Pesticide
Programs, Washington, B.C.
Wilson, James D. 1975. Mirex: decision
making problems in pesticide programs.
Unpublished M.S. thesis, Univ. of Flor-
ida.
FOOTNOTES
1
In addition to other currently registered
pesticides.
Costs were calculated using 1982 prices,
even though costs in future years would be
higher due to inflation.
-------
TABLE 1
PROGRAM:
Aerial eradication
PROGRAM DESCRIPTION: 1. Federal/state financed program to eradicate IF A
2. Three treatments over about 18 months
3. All infested acreage treated
ACRES TREATED:
1. Slow approach
1st year 7 million
2nd year 14 million
3rd year 21 million
4-33rd years 21 million/year
Total acres = 230 million x 3 = 690 million
2. Faster approach (3x the slow approach)
11 years total
21-63 million acre applications per year
TREATMENT COSTS: 1. Slow approach Amdro
2.
1st year
2nd year
3rd year
4-33 years
Total
Cost/acre
$35.00 million
70.00 million
105.00 million
105.00 million
$5.00
Ferriamicide
$17.5 million
35.0 million
million
million
52,
52,
$ 3.45 billion $1.725 billion
$2.50
Faster Approach
Same total as above, but increases sooner, thus
saving costs of inflation.
FEASIBILITY ASPECTS/LIMITATIONS:
1. Legal problems preventing complete area coverage
essential for eradication.
2. Funding limitations—other claims on funds are likely
to have higher social priorities.
3. Speculative nature of the biological success.
4. Program management, logistical and quality control
problems due to program size.
50.1
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TABLE 2
PROGRAM:
Aerial suppression
PROGRAM DESCRIPTION: 1. Federal/state/local cooperative financing
a.
One-third
Fed
State
Local
33%
33%
33%
b.
Fed matching
Fed 50%
State/local 50%
2. Suppression to lower populations in large scale
areas.
Large area treatments are designed to decrease
resurgence. States likely to take initiative on
general areas and number of acres to be treated.
3. Open market sales of chemical for ground
broadcast and mound-to-mound treatment.
ACRES TREATED:
Principal sites
Agriculture; Pastures, hayland, f encerows,
farmsteads, hand labor crops and generally where
problems are most severe
(Some row crops)
N on-agriculture; Lawns, campgrounds, school
yards, other public outdoor meeting places,
cemeteries, etc.
Acres
10-30 million/yr., depending
state/local interest
on financing and
TREATMENT COSTS:
Amdro
Ferriamicide
$50-75 million/yr.
($5.00/acre)
$25-75 million/yr.
($2.50/acre)
FEASIBILITY ASPECTS/LIMITATIONS:
1. Funding limitations could be quite significant.
2. Some legal problems, but less severe than
eradication.
50.2
-------
TABLES
PROGRAM:
Aerial relief (subsidized)
PROGRAM DESCRIPTION: 1.
Individual landowner pays one third of total
cost of treatment ($1.66/acre for Amdro and
$0.83/acre for Ferriamicide)
Federal/state pay remaining 2/3 of cost
Temporary relief to individual property owners
with more rapid resurgence than with large scale
suppression program. Treatment lots would range
in size from 40 acre minimum
Open market sales of chemicals for ground
broadcast and mound-to mound applications
ACRES TREATED:
1. Principal sites
Agriculture; Pasture, hay, intensive labor crops
and especially farmsteads.
Non-agriculture; Lawns, school grounds,
campgrounds and other public places
2. Acres/yr.:
Amdro Ferriamicide
3-5 million 5-10 million
ANNUAL TREATMENT COST: Amdro
Landowners
State/Fed.
Total
Ferriamicide
Landowners
State/Fed.
Total
$ 5-8.3 million
10-16.7 million
15-25.0 million
$ 4.1-8.30 million
8.4-16.75 million
12.5-25.00 million
FEASIBILITY ASPECTS/LIMITATIONS:
1. Operational and legal problems do not
appear to be critical.
2. Dependent upon availability of public funds
which may have higher priority uses.
50.3
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TABLE 4
PROGRAM: Landowner Relief (no subsidy)
PROGRAM DESCRIPTION: 1. Individual landowner pays total cost of treatment
($6.00/acre for Amdro and $2.25 for Ferriami-
cide).
2. Temporary relief to individual property owners
with more rapid resurgence than with large scale
suppression program.
3. Open market sales of chemical for aerial and
ground broadcast and mound-to-mound
applications.
ACRES TREATED: 1. Principal sites
Agriculture: Pasture, hay, intensive labor crops
and especially farmsteads.
Non-agriculture: Lawns, school grounds,
campgrounds and other public places.
2. Acres/yr.: Amdro Ferriamicide
2-4 million 4-8 million
ANNUAL TREATMENT COST: Amdro
Landowners $12-24 million/yr.
Ferriamicide
Landowners $9-18 million/yr.
FEASIBILITY ASPECTS/LIMITATIONS:
1. Operational and legal problems do not appear
to be critical.
2. Program effectiveness limited where land-
owners lack pest management information for
IF A control.
50.4
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Table 5. Summary of key findings on four sample alternative imported fire ant control program approaches.
Program Approach
Obj ective/scope
Cost
Evaluation
1. Eradication
Complete elimination of
IFA from 230 mil. acres,
over 11-33 yr. period
Amdro
a) $35-315 mil./yr
b) $3.45 billion total
Ferriamicide
a) $17.5-157.5 mil./yr
b) $1.72 billion total
Definitely not prudent due to lack of
feasibility and adequate resources;
severe legal problems. (e.g.
environmental groups and non-
cooperative landowners)
2. Suppression
(Large area)
Ul
o
3. Subsidized
relief
Sustained control with
minimum reinfestation on
priority land areas
(10-30 million acres
treated/yr.)
Temporary relief to
owners at one third
treatment cost as
requested by owners;
3-10 million acres/yr.,
lawn, school, recrea-
tional, farmstead and
priority ag. lands
Amdro
$50-75 million/yr.
Ferriamicide
$25-75 mil./yr.
Not adviseable, given the level of
benefits to be achieved relative to
costs; significant legal and funding
problems for full scale program.
Amdro
Landowners $5-8.3 mil./yr.
Government $10-16.7 mil./yr.
Total $15-25 mil./yr.
Ferriamicide
Landowners $4.1-8.3 mil./yr.
Government $8.4-16.7 mil./yr.
Total $12.5-25.0 mil./yr.
Feasible; scope depends upon
availability of funding and level
of subsidy per acre treated.
4. Non-subsidized
relief
Temporary relief at
full market price
to landowner
a) Amdro; 2-3 mil. acres
b) Ferriamieide; 4-8 mil.
acres
Amdro
$12-24 mil./yr.
Ferriamicide
$9-18 mil./yr.
Market solution feasible provided no
government subsidies or interference
in market; costs to be incurred in line
with benefits.
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PANELD
THE THEORY OF POPULATION DYNAMICS
Dean L. Haynes, Chairman
Michigan State University
Daniel P. Wojcik, Reporter, USDA-ARS
Gainesville. Florida
John C. Allen
University of Florida
Robert Campbell. USFS
Corvallis, Oregon
C. Ronald Carroll
Baylor University
Ting H. Hsiao
Utah State University
Jesse Logan
Colorado State University
Ron Stinner
North Carolina State University
-------
INTRODUCTION
When studying a group of insects, we are
often overly impressed by their presence
and number. When numbers are high, eco-
nomic entomologists usually locate the point
of highest density and count the individuals.
From this estimate, the "outbreak" is char-
acterized and control recommendations are
presented, with the underlying belief that if
sprays are applied at points of highest den-
sity, we will get the most kill for control
cost and therefore the most benefit. The
complex interactions of a pest population
with its biotic and abiotic environments
renders these assumptions and approaches to
a useless leftover from the chlorinated hy-
drocarbon era. The lack of understanding
about the interaction of individuals within a
Population leads to many, often counter-
intuitive, outcomes. For example, every
individual will die from natural causes with-
out human-imposed controls. Thus, killing a
Pest with a pesticide usually brings about
damage control through population reduc-
tion, but not population control. This fact
appears trivial, but perhaps is the most
significant point in population dynamics.
THE THEORY OF
POPULATION DYNAMICS
When considering the applied and theo-
retical aspects of insect populations, the
Organizational levels where interactions oc-
cur should be considered. Basically there
are four levels of generalized pest insect
groupings: subindividual, individual, popula-
tion, and community. Difficulty raises when
observations are made at one level and the
implications are projected to a different
level. The key to understanding most
"single-organism" populations is the popula-
tion; therefore, individuals must be counted.
This simplistic idea becomes a complex
issue with social insects or what might be
considered as "multi-organism" populations.
For the purpose of this report, we can
define "population dynamics" as a discipline
that studies the factors producing change in
the number and quality of individuals. The
term "population" as it relates to insects is
ill-defined and takes on meaning only from
the context in which it is used. As such, one
ecological definition might be: a population
is a group of individuals sharing a common
gene pool. Unfortunately, the operational
definition is usually: a population is a group
of individuals occupying an area defined by
our concern for considering it as a popula-
tion.
Thus, a crop pest becomes defined as a
population with little concern for its linkage
with other individuals outside the crop. This
operational differential may be a philosophi-
cal side effect of using pesticides. Pesti-
cides applied to the crop kill a large number
of insects present or soon to arrive. Defin-
ing the population as individuals living or
dead in the crop results in high kill statis-
51
-------
52
tics. If 1% of a population resides in a crop
and 99% are killed, it is not very impressive
to state that slightly less than 1% of the
population was destroyed.
In a community, groups of individuals
live together in some sort of natural order.
The temporal and spatial aspects of a com-
munity do not need to coincide with a
specific population. Communities are com-
plex biological, social, and ecological webs.
Managing such structures could be the most
important, and largely untapped, non-chemi-
cal control method for any species. Thus,
community structural modification research
should be a high priority.
Adding the word dynamics to population
implies a change over time. To understand
this, it is essential to realize that a popula-
tion is distributed over time and space. The
spatial distribution is normally used during
pest surveys, with results expressed as pests
per sample, pests per field, etc. The tempo-
ral aspects such as age structure and popu-
lation maturity and distribution, are seldom
addressed even though they are equally im-
portant. Both spatial and temporal aspects
of a population interact in a way that ap-
pears to be opposite or in conflict with
simple intuition.
For example, Figure 1 is a typical prob-
lem associated with sampling insect num-
bers to compare spatial differences. The
population remains relatively constant until
March, when it reproduces rapidly until
May. Natural mortality causes a decline
until November. Sampling this population
would result in densities varying from 10 to
60 on this theoretical curve. The significant
parameter represented by this graph is not
the six-fold difference in density, but the
generation index of I equal to one where I =
(density March 1, year 1) f (density March
Reproduction P«rhd Mortality Period
C
k. O-
C
a o
0
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53
gy has analyzed factors that limit or control
Population numbers, and the relative impor-
tance of abiotic and biotic components of
the habitat have been argued. Only recently
have individual populations and community
structure been linked in highly interdepen-
dent models representing natural systems.
Linkage between abiotic factors and the
biotic components of the ecosystem can be
direct and indirect, with or without time
delays. Since these linkages and interrela-
tionships are often complex, a sound theo-
retical framework is helpful for interpreting
the effects that management practices may
have on population performance and com-
munity structure.
DIFFERENCES IN PESTS
In American agriculture there appears to
be four classifications of "emergency pest
Problem," each requiring a different pest
management response:
1. Exotic pests: These are newly-intro-
duced pests whose populations rapidly ex-
Pand to high numbers before slowly adapting
to the new environment. Insects in this
category are cereal leaf beetle, gypsy moth,
imported fire ant (IFA), Japanese beetle,
winter moth, European pine sawfly, Essex
skipper, European skipper (McNeil 1975),
and alfalfa weevil.
2. Native pests with cyclic outbreaks:
Because they are so closely tied with the
environment, these pests go through perio-
dic outbreaks. Pests in this category would
include spruce budworm, grasshopper, range
caterpillar, hemlock looper, bark beetle,
etc.
3. Native species with expanded range:
This pest species exists in limited geograph-
ic areas or environmental habits and adapts
to new hosts or climate conditions. Insects
such as the Colorado potato beetle, bean
leaf beetle (Dietz et al. 1976), apple mag-
got, boll weevil, and corn rootworm belong
in this category. Included could be pests
developing additional generations in re-
sponse to agricultural production practices,
or the release of resistant varieties (e.g.,
Hessian fly). Pests developing resistance to
chemicals also could fall with this category.
4. Induced outbreak: This category in-
cludes most secondary pest insects that
build up in pesticide-impacted environments
when the pesticide is not directly applied
for their control. The category would in-
clude such pest species as spider mites,
aphids, and numerous lepidopteran pests.
The response by governments and similar
institutions to pest outbreaks needs to care-
fully consider the unique population char-
acteristics associated with each category.
An effective management response may be
very different for each situation, and a
single control option may have very differ-
ent outcomes in different classifications.
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54
ECOLOGICAL PHASES
OF INTRODUCED PESTS
In this section, we will track the ecologi-
cal progression of an introduced (exotic)
pest as it adapts to its new environment.
During a new introduction phase, the
insect rarely is adapted to or closely cou-
pled with the ecosystem. At this time, the
abiotic environment exerts several pressures
on the insect population. It determines the
physiological limits for colonization and
whether the insect will survive. Under-
standing the physiological limits will help
determine how successfully the species will
colonize. Knowing how climate affects sur-
vival and movement will help determine how
effective a pest the insect might become.
Also, understanding the abiotic effects on
the population will aid in predicting whether
the new introduction or indigenous species,
occupying the same niche, will be favored in
a competitive interaction. These predic-
tions will be useful when evaluating man-
agement tactics. For example, a broad
spectrum biocide that disrupts existing com-
munities could lead to a more successful
establishment of an introduced species.
After the new introduction phase, in-
sects go through a physiological adaptation
stage. Life table analysis of this phase
could indicate windows of vulnerability in
the pest's life system, such as periods of
stress. Exploiting these vulnerable times
could result in successful management
strategies (i.e. disrupting overwintering
sites). Included in this phase is genetic
adaptation. During colonization, insect
pests are subjected to new selective pres-
sures as a consequence of changes in the
abiotic and biotic components of the envi-
ronment. Populations that succeed in sur-
viving the genetic selection may have ac-
quired a radically altered, balanced, genetic
system. Such genetic evolution is observ-
able in terms of morphology, physiology,
behavior, and life history traits. The alter-
ations can be so drastic that the introduced
population can be considered to be a new
race or even a new species, complete with
pre- and post-mating isolating mechanisms.
In terms of pest control, this means that an
introduced species has, in its new environ-
ment, the potential to evolve in an unfore-
seen manner (Templeton 1979).
The final phase of colonization is the
successful physiological adaptation of the
insect. At this time both competitive and
predator/parasite relationships are impor-
tant, which typically results in the pest sta-
tus of the introduction being less than the
previous stage. Again, abiotic factors may
alter competitive relationships between the
pest and its natural enemies.
By knowing the effects that weather,
community structures, and their interac-
tions have on pest populations, it is possible
-------
55
to predict when and where pest populations
will occur. This information also can be
used to avoid control tactics that adversely
disrupt the system. Humans can greatly
impact the natural evolution and adaptation
of exotic species to its new environment by
stopping and, in some cases, reversing this
natural progression.
THE WORLD: A BUG'S POINT OF VIEW
Elephants and hippos do not get caught
>n water surface tension. Insects do. Un-
derstanding the needs and dynamics of a
Population requires that we imagine things
in the way that a species must see them.
The microclimate experienced by a particu-
lar species is not necessarily that reported
by the U.S. Weather Service or measured in
* weather shelter. Often that species has
evolved over millions of years to become
adapted to a particular environmental niche.
The fact that is becomes a pest may simply
be a consequence of our inadvertently ex-
panding its niche space a million-fold or so
with bulldozers and tractors or accidental
movement. When this happens, we might
consider possible ways to shrink the micro-
climate niche space. If this can be done
While still achieving system goals, then the
Pest may be reduced to non-pest levels.
Understanding the microclimate of the pest
could lead to the development of interesting
management options. The literature is re-
plete with such examples.
OPPORTUNITY IN A CRISIS
A unique opportunity exists in social
insects to research the effects of individual
quality on population dynamics. By defining
a colony of social insects as an "individual,"
the individual quality and its effects on the
population of such individuals becomes
easier to research and model. Model resolu-
tion increases. In fact, for a community of
ant species, many levels can be identified
and measured fairly easily. Levels start
with a species; within a species there is an
age of nest; within that level there is a
distribution of ant types; and within that
level there is an age distribution. This
complexity is measurable for most insect
populations only with enormous resources.
For ants, however, the within-nest dynamics
can be measured and studied fairly easily;
the direct effects of changes of within-nest
distributions (age and type) can also be
modeled. Such models will help integrate a
research program much more than is usually
possible. With increasing complexity models
become more realistic, which increases the
level of understanding of the population and
its interactions. This is particularly true
when measuring abiotic stress on within-
nest dynamics. Models that effectively
incorporate abiotic stress are difficult to
develop for non-social pest populations.
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56
POPULATION ANALYSIS
Measuring an Abstraction—Determine
Sampling Attributes
All populations share certain life pro-
cesses. For example, the development rate
of all insects is temperature-dependent.
Thus, both physiological and chronological
time scales should be used when measuring
life processes. Many processes that occur
(e.g., reproduction, mortality, movement)
are related to the density of the target
species and/or other species.
An important concern in dealing with
social insects is that different processes
affect the individual and the colony differ-
ently. Understanding the individuals' dy-
namics does not necessarily imply a knowl-
edge of colony dynamics and vice versa.
Because of this hierarchy, it is imperative
that processes be examined at the appropri-
ate level. Thus, if one is concerned with
managing a social pest and the target is the
colony, colony dynamics should be most
closely examined. Given this background,
the major sampling considerations are:
(a) selecting the sampling entity (indi-
vidual, cluster, colony),
(b) selecting the sample unit (square me-
ter, soil type, habitat, etc.),
(c) selecting the spatial and temporal
sampling intervals,
(d) determining the type of distribu-
tion^) observed and any changes
associated with other population and
habitat characters, and
(e) calculating the sampling schemes for
various specific objectives.
All sampling plans must provide error
estimates and make variance partitioning
possible. The necessary data to establish
these sampling attributes can come from
early phases of concurrent research that
includes changes in (1) the pest: numbers of
individuals and individual attributes, and (2)
the environment: physical and other or-
ganisms (plants, competitors, enemies, and
commensals). In social insects, where the
unit of study may not be the individual, nest
or colony characters have to be measured to
give the colony some specifically identifi-
able states (i.e., all colonies are not equal).
These studies should be conducted exten-
sively (coarser sampling over wide areas)
and intensively (including the extreme situa-
tions).
Population behavior of new invaders,
such as the IF A, may change dramatically
through time. Inferences drawn from the
study of invading populations along the ad-
vancing front of an infestation must be
interpreted cautiously. For example, popu-
lations of the sea lamprey virtually exploded
when the species reached the Great Lakes.
Despite aggressive control efforts, preda-
tion on lake trout devastated that fishery.
Now, however, lamprey predation is scarce-
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57
ly a factor in the booming sport fishery for aspects that have immediate management
the several salmonid species introduced applications, or (2) continuing, ad infinitum,
from the Pacific. For this reason, it is studies of relationships having no known
particularly important to encourage studies potential for management.
explicitly designed to detect and interpret
long-term changes in population behavior. ANTS AND WHAT TO LOOK FOR—
Specifically, some areas should be reserved A PARTIAL LIST
for long-range (perhaps 20 to 30 year) stud- As in all other cases, the attributes of a
ies on the population dynamics of the IF A. system are determined by the questions and
From this work, correlations can be hypotheses guiding the study. The following
found between the pest and its environment, example concerns the community dynamics
Typically, these become the basis for gen- of ants. Since the level of study has been
Bating hypotheses about cause and effect defined at the community level, measure-
relationships. These hypotheses need test- ments are restricted to processes that feed
lng. As correlations are developed, empha- into determining community dynamics.
sis should shift toward experimental studies Thus, many features may be excluded en-
designed to test these hypotheses, rather tirely and treated as a "black box." For
than to assume their validity. Initial re- example, for some purposes, the mech-
search should concern hypotheses that ap- anisms of pheromone production and distri-
Pear most crucial to conceptualizing the bution within a nest may be ignored; inte-
Pest system. Since more than two alternate gration of nest activities becomes a product
hypotheses may explain any single correla- of a "black box" hormonal system. How-
tion, the researcher should consider all hy- ever, the decision to exclude the mechanics
Potheses and design research to different!- of a process has to be chosen carefully. For
ftte among them. Once a given hypothesis is example, ignorance concerning the function-
confirmed, the general conceptualization al details of mammalian hormones may be
should be updated. acceptable when studying the interactions
At any time, both the scientist and the of ungulates, but it would be essential to
granting and/or regulatory agency can use rodent interactions where adrenal gland
this construction when making judgments on weight and activity relates to behavioral
current research or management requests, dominance. The point is to be cognizant of
However, both the researcher and involved the role of hormones/pheromones in ant
agencies should avoid (1) studying only those community dynamics and to carefully
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58
choose the level of measurement that meets
the requirements of the guiding hypotheses
and questions.
Some examples and rationales for select-
ing sampling attributes of community dy-
namics of ants include the following, very
incomplete, variables.
1. Species-specific foraging behavior:
Shifts in the time or location of foraging in
the presence or absence of other species
(e.g., McNeil et al. 1978) may indicate im-
portant competitive interactions and could,
under some circumstances, feed into the
community structure.
2. Spatial distribution of nests: For this
study, movement of workers of the same
species from nest to nest validates the use
of the nest as the sampling attribute. The
distribution of nests of each species and
their abundance through space and time is
the appropriate sampling unit to measure
the outcome of community interactions.
The distribution of foraging workers around
each nest may be the more appropriate
sampling unit for measuring the interactive
mechanisms of community change.
3. The dynamics of the community:
Change, resistance to change, and rates of
return to the original community composi-
tion are the focus. Therefore, experimen-
tally, nest distribution is appropriate. For
meaningful results, conditions must be spec-
ified (e.g., which environment, over what
time course, the initial set of populations,
etc.).
SOCIAL INSECTS:
PROBLEM OF DEFINITION AND BIOLOGY
Relative Time as a Problem
and Opportunity
For most pests in annual cropping sys-
tems, the periodicity of the habitat is long
relative to the generation time of the pest.
With many species, the reverse is true. The
lifespan of a particular crop is generally
shorter than the generation time of the
resident social insect colony. Short-genera-
tion pests that spend much or all of their
lives in a single environmental patch should
follow the environment closely (i.e., become
specialized for particular field types).
Long-generation pests and pests with low
dispersal thresholds should be relative field
generalists. Thus, habitat manipulation as a
control procedure for long-generation pests
may have limited success unless the alter-
nating habitats (in time and space) are
chosen on the basis of knowledge concerning
environmental determinants of population
dynamics.
Population Processes
Birth-death processes in social insects
are similar to other organisms, but some
important differences exist. Obviously, the
addition of sterile workers is simply indi-
vidual growth of the colony; the colony is
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59
the organism from the perspective of popu-
lation dynamics. As the colony adds or
subtracts workers and adjusts the caste
composition, the colony changes its ability
to meet the various life contingencies of
reproduction (new sexuals leaving the colo-
ny), competition, nest repair, etc. That is,
the colony has various age or stage-specific
parameters. In cases where queen substitu-
tion occurs, the colony is, in principle, im-
mortal. Concepts, such as reproductive
value, become stage-specific properties, and
'life" expectancies become the set of tran-
sitional probabilities of death associated
with each stage. The possibility of polygyny
(multiple queens) occurring in social species
means that fecundity will be highly variable
within a species; it then becomes necessary
to treat variance as a parameter in a life
system model. Death of queens in poly-
gynous colonies is treated as an effect on
reproductive value. This explanation of
birth-death processes illustrates the equiva-
lent processes in social and solitary species.
These processes, however, may be difficult
to measure.
The colony is a responsive homeostatic
system with many paths for feedback loops
and mechanisms for controlling flow rates
^ong the loops. For example, a colony has
four levels of buffering against the morbidi-
ty effects of a variable food supply.
1. The colony can store food in the nest;
therefore, foraging and harvesting rates are
not limited by the immediate metabolic
needs of the colony. Furthermore, satura-
tion curves for foraging behavior may not be
closely correlated to colony biomass but
may be limited by environmental, temporal,
and spatial patterns of food availability.
2. The ability to change foraging behav-
ior relates to the abundance and distribution
of food outside the nest. For example, an
ant colony may forage by using a few well-
defined trails when food is predictable and
clumped. When food is unpredictable and
dispersed, the colony may switch to diffused
foraging behavior without defined trails.
3. Larval secretions may be used to
feed other larvae and workers, which dis-
tributes the food within the colony to pre-
vent local shortages among some larvae.
4. Larvae may be cannibalized (actually
a form of colony catabolism) as food for
other larvae. There is considerable fine
tuning in this behavior. For example, since
eggs have received little colony investment,
they are the first stages to be used as food.
Sexual larvae are fed preferentially, thus
maintaining reproductive success.
Relatively little seems to be known
about the population dynamics of social in-
sects. Even age at death, a straightforward
attribute of individual insects, may be diffi-
cult to define for a colony or nest. While
the members of this panel had relatively
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60
little experience dealing analytically with
such unique attributes, they judged that
current analytical methods can easily be
modified to incorporate these unique fea-
tures.
GENETIC CONCERNS:
A CASE OF NEGLECT
Problem or Opportunity
Genetic systems of social and non-social
insects are similar in some respects, but
different in others. In non-social insects,
bisexual reproduction of diploids maximizes
genetic exchange and thus maintains a high
level of genetic heterogeneity in the spe-
cies. In social Hymenoptera, males develop
from fertilized eggs and are haploid; the
females, from fertilized eggs, are diploid.
This genetic system is known as haplo-
diploidy (Wilson 1971, Crozier 1977). A
connection between haplodiploidy and the
frequent occurrence of sociality in insects
has been suggested by several researchers.
This system allows considerable inbreeding
and thus maintains a high degree of homo-
geneity among social insects. Recent bio-
chemical evidence from gel electrophoresis
of isozymes reveals that the average heter-
ozygosity of social insects is considerably
lower than that of non-social insects
(Crozier 1977, Ayala 1982). Such low genet-
ic variability in social insects confirms that
there are specific differences between the
genetic systems of social and non-social
insects.
The development of social systems in-
volves many changes in the characteristics
of social species that are not found in non-
social insects. Many behavioral and ecologi-
cal interactions that are integral parts of a
social system have no parallel in non-social
insects. Regarding the reproductive poten-
tial, social insects are often thought of as
having unusually high fecundity. The task of
reproduction in social insects, however, is
carried out by one or a few reproductives; in
non-social insects, all females contribute to
the reproductive task. When comparing
populations, the reproductive potential of
the two insect.systems is probably similar.
A special feature of social insects is that
the reproductives are protected in the nest
and are seldom subjected to adverse envi-
ronmental conditions. Since most of these
species have a long generation time, they
are less affected by natural selection pres-
sures. This may be one of the reasons why
social insects appear to develop resistance
to insecticides at a much slower rate than
non-social insects.
Community Analysis
Performance of a population depends on
the combined effect of the individual attri-
butes of the population plus the total inter-
actions of other populations occupying the
same geographic region. Analysis of the
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61
nature of the interactions between popula-
tions, and the results of these interactions
in terms of stability, persistence, and domi-
nance, is the topic of community ecology.
Community ecology, therefore, can be used
in understanding the effects of complex
interactions (i.e., competition and preda-
tion) on the abundance of particular pest
populations.
For an introduced pest, which progres-
sively becomes more adapted to new ecolo-
gical associations, particular community-
level associations may be more important
during certain phases of adaptation than at
other times. For example, during the early
stages of colonization, competition with na-
tive species occupying a similar niche would
be the most important community-level as-
sociation. In later phases of adaptation,
relationships with natural enemies would be-
°o ne important.
A C VSE FOR MODELING
•ur understanding of the actual popula-
tion dynamics of organisms can be greatly
enhanced by considering the diversity of
behavior of population models. Even very
simple models of a single species can exhibit
a vast array of possible behaviors. This type
°f complexity can usually be obtained by
varying the "constants" in the model, which
18 analogous to making them functions of
tirne or space in a very general sense (to
what actually happens in the real, "non-
constant" world). That very simple models
of one or two species exhibit complex be-
havior when subjected to this type of anal-
ysis is encouraging to the population biolo-
gist. It implies two things: (1) predicting
complex behavior of the real world is within
the scope of relatively simple models, and
(2) real world complexity can be reduced to
simple components.
Simplistic population models showing
that a wide array of behavior is possible also
says something to humans about population
management—ecological communities will
not have simple responses to simple inputs.
Surprises will be the order of the day.
There are no simple rules—just exceptions.
Good management is possible, but it must be
long-range and founded on knowledge.
Given the complexity of the simplest ecolo-
gical community, ill-considered, forceful,
management attempts will simply produce
large perturbations with uncertain conse-
quences. The worst enemy is ourselves—our
haste for a quick, simple solution, rather
than a desire to understand the problem
(Stinner 1982).
HIGHER ORDERS OF INTERACTION
The environment largely determines how
a community will move through time and
space. By varying the "constants" in simple
models, very complex behavior can be ob-
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62
tained. Therefore, when these "constants"
in a community are actually environmental
functions, the environment drives the com-
munity dynamics. Even the most gross level
of dynamics (e.g., establishment of a new
species) is obviously a function of tempera-
ture, rainfall patterns, etc. Therefore, it
should not be surprising that even simple
species interaction models display remark-
ably different behaviors in response to only
one variable, like temperature. As temper-
ature changes, a pest and its natural enemy
may change in their interaction from
damped cycles to constant cycles to in-
creasing cycles to chaotic behavior. This
change in behavior could occur over the
course of an annual cycle or over the spe-
cies' geographic range in response to tem-
perature. We must understand that simplis-
tic thinking about biological responses to
environmental influences is not likely to be
correct. The rich diversity of possibilities
will not be predictable.
In agricultural systems, perhaps exclud-
ing tree crops and permanent pastures, com-
munities of pests are unlikely to be at near-
equilibrium conditions. Under these condi-
tions, much community ecology theory is
inapplicable. The appropriate development
of a theoretical basis for an agricultural
community ecology should consider the fol-
lowing:
1. Perturbation analysis with an empha-
sis on resistance and resilience.
2. Methods of analysis, e.g., loop analy-
sis as developed by R. Levins, appropriate to
complex systems where many interactions
can be expressed only in qualitative form.
3. The relationship between changes in
the connections between species and what
happens to the form of stability. This
requires an analysis of the hierarchical pat-
tern of species links within the community.
It is important to identify subsets that are
connected to the rest of the community by
single links.
4. The relationship of resource utiliza-
tion curves as a function of community
composition and local habitat. In other
words, in which habitat and for which per-
mutation of species mixtures do we find
minimum and maximum overlaps in species
resource utilization curves.
The goal is to develop procedures and
generalizations such that community level
management can systematically and pre-
dictably determine the probability of inva-
sion by a new species. With regard to the
IF A, it is frequently asserted that no natural
enemies or important competitors exist.
Since the IF A is abundant and expanding its
range, the IFA seems to be independent of
competition and predation from other spe-
cies. However, this assumption ignores the
reality of considerable local variation in
nest density and colony abundance. When
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63
the IF A is abundant it is said to lack com-
petitors and predators, but when it is
scarce, the IF A is said to be in a "poor
habitat." Thus, the possibility of biotic
controls on IF A population dynamics is se-
roantically excluded. Clearly, the proper
natural laboratory for the study of the popu-
lation dynamics and community ecology of a
Pest is across an array of habitats where the
proportional representation of the pest in
the community ranges from "frequently ab-
sent" to "usually abundant."
CONCLUSIONS
Research and Resources
As applied biologists, we often have
heard: "The problem is here now! We must
do something! We cannot wait for re-
search." If this policy of ignorance were
only words and not subsequent budget ad-
justment, there would be more hope. There
^e at least two ways to manage crisis: one
is to prepare a program of action in ignor-
ance, and the other is to prepare a program
where at least one outcome is a significant
increase in our understanding of the prob-
lem. Research does not have to be consid-
ered as a noble human endeavor conducted
outside of immediate need or, conversely,
conducted solely for the purpose of immedi-
ate application. Both approaches perpetu-
ate our initial ignorance for future consid-
epation. Neither has a high probability of
success. Our lack of basic understanding of
IFA population dynamics after more than
two decades of government response is a
specific case in point. The policy, "the only
good insect is a dead insect," has not worked
and cannot be expected to work. It should
be a given policy that, in any control re-
sponse (eradication, containment, manage-
ment), failure is possible. Thus, modest
funds should be provided for long-term study
of the population dynamics of the species at
the onset (or certainly within six months) of
eradication attempts.
Historically, there has been a strong
reluctance to provide these funds since it
admits potential failure of the present pro-
gram. If it was a general policy to provide
research funds, then the political problems
associated with an admission of potential
failure are avoided. All efforts at challeng-
ing a newly invading species should include
an initial conceptualization of the popula-
tion dynamics of the species. This construct
must be flexible and should be updated as
new information is obtained.
To blame institutional response totally
for perpetuating biological ignorance of in-
vading pests would be a gross oversimplifi-
cation of the problem. Clearly institutional
inertia and political expediency are domi-
nant factors in resource allocations for pro-
gram development. However, the lack of
resources for basic population research can-
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64
not be strongly implicated in closing minds
or the inability to conceptually interpret
existing information and theory related to
other animal populations.
Economic entomologists and pest control
specialists in particular dwell on the unique-
ness of each pest subdivided into each crop.
If, on the other hand, biologists were looking
for theoretical bases for examining appar-
ently dissimilar events, a great deal of in-
formation could be brought to bear on par-
ticular problems. The case in point is that
IF A research should look for population
principles in other pest species instead of
treating IFA characteristics as if they were
unique.
Single Factor Control
In given pest situations we tend to at-
tack the pest directly with mortality agents
whose action is often non-specific. Natural
enemies, competitors, and disease agents
may be exerting a very high, and continuing,
mortality on the pest despite its pest status.
If this complex is disrupted, the pest, usual-
ly having a high reproductive potential, is
released from much of its mortality pres-
sure. The result is the often observed pest
resurgence phenomenon; in addition, new
pests can be created by indiscriminately
removing their mortality agents. Thus,
knocking out a section of a community with-
out being sure of what will happen can
produce undesirable surprises.
Community Structure
We must understand and manage at the
community level. We are part of the com-
munity that we seek to manage, and we
cannot escape its feedback if we completely
ignore its structure and proceed in heavy-
handed ignorance. The scientist needs time
and support to obtain the basic knowledge
necessary for any intelligent management
program. Large-scale programs covering
millions of acres should never be undertaken
until a high level of understanding of the
system.has been obtained. In fact, in many
situations, once that level of understanding
is obtained, we will probably have resolved
the system into several sub-systems each
requiring a somewhat different program of
management. There are few simple solu-
tions to managing community ecosystems.
If we apply the intelligence we have to the
management of ecosystems, we probably
can be successful in many cases. If we do
not apply that intelligence, it is most likely
that the ecosystems we seek to manage will
control us.
Genetic Analysis
Genetic analysis of insect populations,
especially pest species, has been a neglected
field of research. Extensive research data
will be needed before any generalization can
be made about the genetic systems of pest
species. Since population is the basic unit
of ecology and evolution, the study of gene-
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65
tic variation should be focused at the popu-
lation level to determine the genetic com-
ponents that influence population processes.
Many fruitful approaches are available for
genetic analysis of social and non-social
insects. Techniques such as chromosomal
karyotype analysis, gel electrophoresis of
isozymes, and DNA sequence should be rou-
tinely used for genetic studies. In addition,
various ecological, physiological, and beha-
vioral traits of pest species should be moni-
tored to determine population variations.
Traditional crossbreeding experiments will
also be needed to define genetic mecha-
nisms of inheritance. Since most of these
studies require a long time, adequate dura-
tion of time and financial support must be
available for such research programs.
Evidence of high genetic variability in
insects reflects the tremendous evolutionary
Potential of pest species; control programs
should be designed with this in mind. Pro-
bably no single perfect control method
exists against an insect pest since the insect
is likely to evolve resistance. However,
evolutionary theory predicts that an insect
Pest is far less likely to evolve resistance to
a control program where many strategies
a?e used. In general, therefore, a control
Program that incorporates multiple ap-
proaches is the best type of program. In
°rder to employ multiple-approach control
strategy, basic knowledge of the ecology
and genetics of pests and related species
must be available, and only through applica-
tion of such knowledge can the control op-
tions that exist and their respective risks be
dealt with. Therefore, for the development
of a long-term control program, there is an
immediate and critical need to increase
basic research on the ecology and genetics
of pests and related species.
RECOMMENDATIONS
1. Funds should be provided for long-term
study of the population dynamics of the
pest species at the onset of any eradica-
tion trials for any pest.
2. Research on the IF A should examine the
population dynamics of other pest
species and compare them to the IF A.
3. Single-factor control should not be a
priority in control strategies, rather
emphasis should be placed on multi-
factor management strategies.
4. A conceptual framework for dealing with
the population dynamics of the IF A
needs to be developed.
5. Modern experimental design, analytic,
and measurement tools should be used to
study the population dynamics of the
IF A.
6. A workshop of researchers studying pop-
ulation dynamics of the IFA and of other
species should be held to pool knowledge
and develop a sound system for studying
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66
the population dynamics of the IF A.
REFERENCES CITED
Ayala, F. J. 1982. The genetic structure of
species, pp. 60-82 in Milkman, R. (ed.),
Perspectives on Evolution. Sinauer As-
sociates, Inc., Publ. Sunderland, MA.
Crozier, R. H. 1977. Evolutionary genetics
of the Hymenoptera. Ann. Rev. Ento-
mol. 22:263-288.
Dietz, L. L., J. W. Van Duyn, J. R. Bradley,
Jr., R. L. Rabb, W. M. Brooks, and R. E.
Stinner. 1976. A guide to the identifi-
cation and biology of soybean arthropods
in North Carolina. N.C. Agr. Exp. Stn.
Tech. Bull. 238. 264 pp.
McNeil, J. N., J. Delisle, and R. J. Finne-
gan. 1978. Seasonal predatory activity
of the introduced redwood ant, Formica
lugubris (Hymenoptera: Formicidae) at
Valcartier, Quebec, in 1976. Can. Ento-
mol. 110:85-90.
McNeil, J. N., R. M. Duchesne, and A. Co-
meau. 1975. Known distribution of the
European skipper, Thymelicus imeola
(Lepidoptera: Hesperiidae), in Quebec.
Can. Entomol. 107:1221-1225.
Stinner, R. E. 1982. La lutte integree—une
perspective. Phytoprotection (in press).
Templeton, A. R. 1979. Genetics of colon-
ization and establishment of exotic spe-
cies, pp. 41-49 in Hoy, M. A., and
McKelvey, J. J. (eds.), Genetics in Rela-
tion to Insect Management. Rockefeller
Foundation.
Wilson, E. O. 1971. The Insect Societies.
Belknap Press of Harvard Univ. Press,
Cambridge, MA. 548 pp.
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PANELm
POPULATION DYNAMICS OF THE IMPORTED FIRE ANT
Fowden G. Maxwell, Chairman
Texas A &. M University
W.A. Banks, Reporter, USDA-ARS
Gulf port, Mississippi
J.L. Bagent
Louisiana State University
W.L. Buren
University of Florida
Oscar Franke
Texas Tech University
Steven Risen
Cornell University
Ann Sorenson
Texas A &. M University
W.L. Sterling
Texas A &. M University
Jerry L. Stimac
University of Florida
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INTRODUCTION
The imported fire ants, Solenopsis rich-
teri Forel and Solenopsis invicta Buren were
introduced into the United States in the
early 1900's and late 1930's, respectively, at
the port of Mobile, Alabama. The spread of
these ants, primarily S. invicta, from this
area was dramatic. Surveys conducted by
the U.S. Department of Agriculture in the
late 1940's and early 1950's revealed that
IFA were present from Miami, Florida, to
San Antonio, Texas, and as far north as
Memphis, Tennessee, and eastern North
Carolina. Today it is found on about 240
million acres in ten states; within this geo-
graphic area, mound densities range upward
to 600 per acre. S. invicta, the red IFA,
occupies over 95% of the infested area,
while S. richteri, the black IFA, infests
northern Mississippi and Alabama.
IFA are found in many habitats, but tend
to favor open or sparsely-forested areas.
Levels of infestation vary widely within the
habitat types. However, the factors influ-
encing these levels are not clearly defined.
EXTRINSIC FACTORS
Abiotic
The role of abiotic factors, especially
temperature and humidity, on the distribu-
tion and abundance of IFA are being investi-
gated. Because the IFA prefer high relative
humidities and moderate temperatures, they
probably will not spread further north, al-
though they may be able to survive in pro-
tected areas if accidentally introduced.
Natural spread of S. invicta through the
desert southwest will be very slow if it
occurs. However, based on comparisons
with closely related Solenopsis species, S.
invicta probably can establish and survive in
the southwest and along the west coast.
Artificial introduction by human activities
may greatly hasten spread through this area.
The effect of moisture (mode, amount,
and timing) on reproductive potential is un-
clear. Variability in this factor may strong-
ly influence the ability of the ant to produce
mating flights and colonize the southwest
and far west.
Biotic
Despite intensive searches, no effective
parasites or pathogens on the IFA have been
found in the U.S. Predators have been
found, but their role in regulating IFA popu-
lations has not been studied in depth. S.
invicta queens are attacked and killed by a
variety of predators from the time they
take flight until they successfully establish
a colony. Neivamyrmex opacithorax has
been reported to prey on larvae of S. rich-
ten' Also the thief ant, Solenopsis moles-
ta, has been found living in the nests and
preying on the eggs and young larvae of both
IFA species. In southern Mississippi, the
ant, Paratrechina melanderi, has been found
67
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68
preying on S. invicta eggs.
The IF A in South America are beset by a
number of diseases, parasites, and competi-
tors. Thus far, none of these have been
shown to influence population density; how-
ever, this may reflect a lack of detailed
studies that could be alleviated if long term
research in South America were performed
by competent scientists provided with ade-
quate technical support.
Although no definitive studies have been
conducted on habitats prior to and as the
IF A colonizes an area, observations indicate
that the IFA populates new areas with 15 to
40 mounds per acre. In areas where control
measures have been applied or other ecolog-
ical disturbances have occurred, a large
number (100+ per acre) of small colonies
may establish a year or two later. In time
the number of colonies decreases to predis-
turbance levels or higher. These temporal
changes in IFA populations may be due to
intraspecific competition among S. invicta
colonies and interspecific competition
among S. invicta and other ant species.
Such inter- and intraspecific competition
needs to be studied.
S. invicta is an efficient colonizing spe-
cies with a high reproductive capacity and
excellent dispersal and habitat-finding abili-
ties. This opportunistic species thrives in
areas where lands are disturbed by any
means (e.g. flooding, cultivation, and insect-
icide applications). In addition, once the
IFA successfully colonize an area, there are
no known competitors that can displace the
IFA. Therefore, any management strategy
should be directed at imposing mortality on
IFA queens at rates that are discriminantly
higher than mortality imposed on other ant
species. Control tactics imposing indiscrim-
inant mortality on all ants may strongly
select for proliferation of the IFA.
INTRINSIC FACTORS
Reproductive Potential
One of the primary reasons for the suc-
cess of the IFA in the United States has
been their reproductive potential. The num-
ber of reproductives, frequency of flights,
and climatic conditions are major factors in
determining distribution and rate of spread.
Most IFA mating flights occur during late
spring and summer, but they may fly any-
time during the year. Studies have shown
that flight range depends on wind speed,
rainfall, and temperature. Most queens land
within a few miles from the source, but
distances up to 12 miles have been docu-
mented, and it is suspected that the range
may be much greater. Rate of spread has
not yet been accurately ascertained.
An IFA colony may produce three to five
thousand queens per year. Winged (alate)
forms were trapped leaving mounds in four
habitats in north Florida, and it was esti-
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69
mated that an average of almost 100 thou-
sand alate queens flew from the mounds in
one acre during one year. Most queens die
during and after their mating flight; how-
ever, only a few queens need to survive to
start new colonies. For example, if an acre
is infested with 30 mounds, only 30 or 0.03%
of 100,000 queens need to survive to replace
the original population. Within the indi-
vidual colony, large numbers of worker ants
can be produced. Recent observations on
colony growth within the laboratory indicate
that most colonies one year or older contain
at least 100 to 200 thousand workers.
Nest Site Selection
Newly-mated queens may select poten-
tial nesting sites during flight and after
landing. Selection appears to be based on
surface properties (e.g., moisture, soil type,
topography, and reflectance). This behavior
results in colonies being established in road-
sides, playgrounds, shopping malls, housing
developments, lawns, pastures, and some
croplands. Heavily shaded areas (e.g., for-
ests) are rarely infested.
Generation Time
Mean generation time is partly influ-
enced by the time of year the colony is
founded. However, 6- to 12-month old colo-
nies can develop reproductive forms and
stage mating swarms. With respect to mean
generation times, no life tables (birth and
death rates, age specific mortality) have
been prepared for any IF A species on any
part of their geographic range. These data
are fundamentally important for sound man-
agement decisions.
Genetics
No studies have been conducted on the
genetic diversity of S. invicta populations.
If the original IF A inoculum into the U.S.
was very small, there may be significantly
less genetic diversity in the U.S. than in the
South American population. The diversity
of the U.S. population could affect the rate
of spread of IF A to new habitats and the
rate of evolution of resistance to various
control measures.
Development
The ontogenetic development of individ-
ual ants has received some attention in the
laboratory, as has the influence of some
abiotic and biotic factors on the rate of
development. The underlying principles of
colony foundation, growth, and development
are broadly known, but the role of ecologi-
cal factors on the rate (i.e., the dynamics)
of the process needs to be quantified.
Feeding Behavior
Because the IF A can exploit many dif-
ferent food sources, there are no known
limits to its distribution based on feeding
behavior. IFA colonies can survive consid-
erable worker mortality because, under con-
ditions of stress, feeding behavior is di-
rected towards maintaining the queen. The
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70
present understanding of the dynamics of
food distribution within the colony may re-
sult in the design of more effective bait
formulations. Temporal changes in feeding
preferences can affect management strate-
gies where baits are used.
Endocrine Systems
Understanding the IFA endocrine system
may lead to control tactics that affect
colony integration and development. The
endocrine system of IFA has been studied
mainly from the standpoint of caste deter-
mination. Juvenile hormones play a major
role in this. Juvenile hormone analogues
that can severely disrupt the reproductive
processes of IFA are being extensively
studied as potential control agents.
Pheromones
Queen pheromones help regulate the
social organization of the nest and influence
reproductive potential. The queen attrac-
tant/recognition pheromone ensures that the
queen is fed, groomed, and protected by her
workers. This same pheromone is applied to
eggs as they are laid, causing workers to
care for the eggs. Queen pheromones regu-
late reproduction by (1) producing new
queens (caste determination), (2) suppressing
egg laying by virgin queens in the parental
nest, and (3) causing workers to execute
queens. These regulatory queen pheromones
have considerable potential as control
agents. Several components of the attrac-
tant/recognition pheromone have been
chemically identified, and synthetic mater-
ials are currently being evaluated for bio-
logical activity.
The IFA also produce a brood pheromone
and a trail pheromone. The brood phero-
mone elicits tending behavior by the work-
ers to the larvae. The trail pheromone
directs workers to newly-discovered food
sources; some of its chemical components
have been identified. These may be used to
enhance the attractiveness of baits. The
special advantages of using pheromones in
control programs are that these naturally
occurring compounds are highly specific to
the IFA and should be environmentally safe.
BENEFICIAL AND DETRIMENTAL
ASPECTS
Cotton
In the cotton agroecosystem, the IFA is
both detrimental and beneficial. Negative
effects occur from IFA stings to workers
when hoeing, harvesting, or repairing equip-
ment. The IFA is beneficial in controlling
cotton pests, such as boll weevils. When
four IFA's are found per ten plant terminals,
boll weevils will be controlled 90% of the
time. IFA are also considered to be a key
predator of Heliothis species, such as the
bollworm and the tobacco budworm. How-
ever, many natural entomophages feed on
these Heliothis species, so if the IFA were
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71
removed, other entomophages may still
maintain these pests below economically
damaging levels.
Mound sampling is not an effective way
to assess IF A density in a cotton field.
During the early part of the growing season
it may be difficult to find mounds in a field.
A "beat bucket" sampler on plant terminals
precisely determines the abundance of for-
aging worker ants and is useful when making
management decisions for pests of cotton
such as the boll weevil.
The IFA colonize cotton fields early in
the growing season primarily in response to
aphids as a source of honeydew. After
colonization, the IFA tend to aggregate in
the field primarily in response to aphid
aggregation. The dispersion of worker ants
in the cotton field is best described by a
negative binomial distribution.
The IFA may kill other entomophagous
arthropods. They have been observed con-
suming parasites of aphids and boll weevils.
Although the IFA generally are thought to
be effective predators on entomophagous
species, other data indicate that they only
minimally impact the abundance of most
entomophages.
Sugarcane
Although the IFA is generally an excel-
lent predator of the sugarcane borer in
sugarcane fields, at harvest time IFA
mounds may damage equipment and the ants
may sting workers. Some sugarcane farmers
would prefer to live without the IFA simply
because of its sting. However, it is well
documented that the IFA saves the sugar-
cane farmer an average of one to two
insecticide applications per season by feed-
ing on the sugarcane borer.
Sweet Potatoes
The IFA tend to infest entire fields of
sweet potatoes, but greater numbers are
found around the periphery of the fields.
Since all sweet potatoes must be harvested
by hand, even in highly mechanized farms,
IFA create problems with the laborers in the
harvesting process.
IFA prey on the egg and larvae of the
banded cucumber beetle and the sweet pota-
to weevil. When IFA are controlled, both
insects and their damage increase in sweet
potato fields. In fact, the statewide prob-
lem with these two pests increased immedi-
ately after large scale control measures
were initiated for the IFA. More research,
however, is needed to determine if this
resurgence is due partly to the reduction of
predators other than the IFA.
Soybeans
The IFA is considered to be a nuisance
pest on soybeans, grain sorghum, and corn
and may be of economic significance where
ants are very abundant or where seed has
not been well covered at planting. Defini-
tive economic assessments of losses in these
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72
crops is generally not available and there is
a need for additional unbiased research on
the impact of IF A on these crops.
In soybean fields, IFA interfere with
harvest and feed on germinating soybean
seed. Large IFA mounds, particularly
around the borders of soybean fields, fre-
quently clog the cutter blade of combines.
Thus, a problem is posed to the person
removing the ants, dirt, and debris by hand.
IFA prey on several pests and serve as an
important predator on many detrimental in-
sects in soybean fields. Three-cornered
alfalfa hoppers, stink bugs, and several lepi-
dopterous soybean pests are reduced by IFA
predation. Research in Louisiana has shown
that insecticides that reduce IFA numbers
actually increase the number of three-
cornered alfalfa hoppers. No insecticides
at this time give better than 60% control of
this pest—the same control provided by IFA.
Forest
The Nantucket pine tip moth larvae are
significantly reduced by the IFA. This pine
pest infests pine branch tips, causing addi-
tional branching rather than the more pre-
ferred erect growth. The IFA has also been
observed feeding on bark beetles in pine
forests.
Pastures and Hay Fields
The IFA pose a problem with equipment
in cutting hay and with bush-hogging opera-
tions of pastures. Large IFA mounds require
that tractors be run at considerably less
than maximum efficiency. Sickle blades and
bush-hog blades are often broken as a result
of the mounds. In addition, the small hay
bales (60 to 100 pounds), if left on the
ground overnight, attract large numbers of
IFA, making it extremely uncomfortable for
laborers to haul the hay. In general, IFA are
considered a significant nuisance in and
around hay fields and to a lesser degree in
pastures.
The IFA, however, serves as an excellent
predator of ticks, horn flies, and stable
flies. In many areas, the IFA have reduced
lone star tick populations so well that the
tick is no longer considered economically
important. IFA also reduces horn fly popu-
lations, but not as dramatically. Although
leaf hopper numbers are reduced by IFA pre-
dation, it is not known how much actual
damage the leafhopper does to pastures.
Wildlife
IFA may kill young quail, rabbits, and
other forms of wildlife, especially those
that nest on the ground, and therefore, are
more vulnerable during the early hours of
life. The IFA probably are one of many
native predators of these animals, as studies
have not demonstrated reduced abundances
of these animals due to IFA predation.
Song birds, field mice, etc., might be
detrimentally affected by large numbers of
IFA, but no studies document this effect.
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73
Although the Louisiana Department of Wild-
life has documented cases of both young
quail and newly born rabbits being killed by
IF A, they have also shown that quail num-
bers in the primary sugarcane producing
parishes are greater now than they were in
the late 1950's and early 1960's. In addition,
rabbits are as abundant as they were before
the IFA colonized the Florida Parish of
Louisiana.
RESEARCH NEEDS
There are legitimate research needs for
short-term chemical solutions to the IFA
problem in particular areas and for long-
term ecological management of IFA over
the entire area of its distribution. We
address here the biological information
necessary for long-term IFA management.
It is important to recognize that undue
emphasis on short-term chemical solutions
has two important negative consequences.
First, the distribution of available funds will
be disproportionately directed towards
short-term solutions. Second, long-term
IFA management can be more difficult due
to adverse ecological consequences from an
over-emphasis on chemical solutions.
RECOMMENDATIONS
1. Research the basic population dynamics
of the IFA and related ant species in
disturbed and non-disturbed habitats in
the South American homeland and in the
United States.
2. Develop life tables for IFA colonies in
South and North America.
3. Assess potential biocontrol agents (para-
sites, predators, pathogens, and competi-
tors) in Brazil and the United States.
4. Study the factors influencing mating
flights and colony founding, particularly
(a) abiotic factors influencing flight ini-
tiation, mating, and dispersal; (b) intrin-
sic factors influencing readiness to
swarm; and (c) factors influencing nest
site selection.
5. Investigate interspecific competition be-
tween IFA and other ants in vari-ous
South and North American habitats.
Also study interspecific competition in
and on IFA populations found on the
periphery of infested areas.
6. Investigate intraspecific competition
among IFA colonies and the role it plays
in determining population densities.
7. Investigate the intrinsic factors in-
fluencing the production of males and
virgin queens.
8. Continue researching the endocrine and
exocrine systems (hormones and phero-
mones); determine how these regulate
reproduction.
9. Chemically identify pheromones, and
evaluate their potential as control
agents.
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74
10. Analyze the genetic diversity (heter-
ozygosity) of IFA in its South American
homeland and in the U.S.
11. Evaluate the impact of the IFA on pests
and beneficial arthropods in forest and
agricultural ecosystems.
12. Determine how IFA populations effect
wildlife and domestic animals.
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PANEL IV
ENVIRONMENTAL TOXICOLOGY
Robert L. Metcalf, Chairman
University of Illinois
David J. Severn, Reporter, EPA
Washington, D.C.
Earl L. Alley
Mississippi State University
Murray Blum
University of Georgia
Maureen K. Hinkle
National Audubon Society
Herbert N. Nigg
IFAS
William H. Schmid
Allergist
John Wood
APHIS
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INTRODUCTION formation that results from IFA stings and
Repeated failures of massive eradication the hypersensitivity and allergic reactions
programs for the imported fire ant (IFA) that are experienced by perhaps one percent
have focused attention on the benefits and of those who are stung. In some cases, this
risks of the eradication process. The envi- allergic reaction is so severe as to require
ronmental toxicology of the ecosystem com- hospitalization and/or expensive desensiti-
plex where humans and the IFA compete zation treatments. Thus the presence of
directly with one another comprises a large trillions of IFA workers from an estimated
part of the benefit/risk equation. The two 10 billion nests over the infested area rep-
major components are the toxicological and resents a readily defined and unforgettable
human health hazards resulting from infes- experience in environmental biochemical
tation by the stinging IFA and the destruc- toxicology. In appended reports, the panel
tion of wildlife and the pollution of the has summarized knowledge about the fire
human environment resulting from the wide- ant venom—its generic composition and evo-
spread use of persistent organochlorine in- lution (Blum 1982, Appendix A)—and has
secticides. The Panel examined these issues placed in perspective the medical aspects of
in some detail and has summarized these the consequences of IFA attacks on humans
discussions in a series of reports (Appen- (Schmid 1982, Appendix B). These apprai-
dices A through H). sals together with detailed analyses from
Panel I and other components of this Sympo-
IFA VENOM AND HUMAN HEALTH sium should make it possible to characterize
The presence of IFA infestations over a the human risk element of IFA infestations.
10-state area of the eastern and southern The Panel believes that a better assess-
U.S., about 240 million acres (97 million ha), ment of the actual impact of fire ant stings
has brought Solenopsis invicta into direct is essential to the long term management of
conflict with an estimated 40 million inhabi- the fire ant problem. Such an assessment
tants. This conflict has excruciating reality should include (1) epidemiological studies of
to urban and rural dwellers because of the IFA morbidity and correlations between IFA
aggressive stinging behavior of IFA. The densities and incidence of morbidity, (2)
IFA venom contains a unique series of dial- toxicological studies on IFA venom (especi-
kylpiperidine alkaloids together with reac- ally the diakylpiperidine alkaloids), and (3)
tive protein constituents that collectively research on the natural products of the IFA
are responsible for the urticaria and pustule and their potential role as population regu-
75
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76
lators.
INSECTICIDES FOR IFA CONTROL
Environmental toxicology has been cen-
trally involved in the IFA "problem" ever
since organized attempts were first made to
control its spread by the use of insecticidal
chemicals (about 30 years). The insecticides
chosen for control and later eradication
efforts were the hexachlorocyclopentadiene
adducts chlordane, dieldrin, heptachlor, and
mirex. These insecticides can be collective-
ly described as extremely persistent in the
environment, broad spectrum in their toxic
action, highly bioaccumillative with long
residence times in human and animal
tissues, and generally hazardous to a wide
variety of terrestrial and aquatic wildlife.
These insecticides have also been shown in a
variety of animal experiments to be chemi-
cal carcinogens. The extensive usage of
chlordane, heptachlor, and dieldrin for IFA
control from 1957 to 1962 on millions of
acres, produced countless problems in envi-
ronmental toxicology relating to bioaccumu-
lation in human tissues, severe damage to
wildlife, and threats to human health.
The introduction of mirex baits for IFA
control in 1962 represented a step forward
entom©logically, in that control efforts
were more selective for the target pest
(IFA) and dosages were dramatically
reduced from about 2 pounds AI (active
ingredient) per acre for heptachlor and diel-
drin, to 1.7 grams and later to 0.4 grams of
mirex per acre. At first, mirex was touted
as being the perfect insecticide. While
heptachlor and dieldrin primarily killed ants
after they left the mound, mirex, a delayed
stomach poison, allowed foraging workers to
carry the poison back to the nests where it
was transferred to the queen and nestmates.
Mirex, however, proved to be even more
environmentally recalcitrant than chlor-
dane, heptachlor, and dieldrin. Even small
dosages caused serious problems in environ-
mental toxicology of field, stream, wildlife
areas, estuaries, and the human ecosystem.
Mirex is one of the most stable xenobiotics
known. It dissolves in water to about 20 ppb
(parts per billion) and has an octanol/HgO
partition coefficient of about 10,000. Resi-
dues of mirex were found in snails, crayfish,
fish, birds, turtles, vertebrates, and humans.
It accumulated in the brain, muscle, liver,
skin, and tissue of mammals; was resistant
to metabolic attack; was not readily
excreted; biomagnified; leached into soil;
attacked non-target insects; and persisted in
the environment. The Panel has endeavored
to place these toxicological effects and
their ensuing political and sociological con-
sequences in perspective in the appended
papers (Metcalf 1982, Appendix C; Hinkle
1982, Appendix D).
In 1973, EPA prohibited mirex from
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77
being sprayed in coastal counties or broad-
cast on aquatic and heavily-forested areas.
In 1977, mirex was phased out of use as an
insecticide; Mississippi was permitted to
apply mirex on mounds and ground broad-
cast. The pesticide registration of mirex
was cancelled on June 30, 1978.
Once the environmental toxicology of
mirex baits for IF A was recognized, more
rational methods for insecticide use were
explored. Significant progress was made in
understanding the environmental degrada-
tion of mirex and characterizing the lexico-
logical properties of the degradation pro-
ducts. From this information a new formu-
lation, ferriamicide, was developed (Alley
1982, Appendix E). Ferriamicide incorpor-
ated mirex (0.05%), ferrous chloride hexahy-
drate (0.2960, and soybean oil (8%) to pro-
mote more rapid photolysis and faster envi-
ronmental degradation.
Field degradation studies showed that
after three years, only 20% mirex was found
in plots treated with a 300-fold application
of ferriamicide. The added amine and fer-
rous chloride components were shown to
reduce the half life of mirex from 12 years
to about 0.15 years. Such accelerated
degradation was felt to result in decreased
problems with bi©accumulation and biomag-
nification.
The use of ferriamicide, however, also
posed problems in environmental toxicology.
Its principal environmental degradation pro-
duct is photomirex—a highly toxic and car-
cinogenic product. The State of Mississippi
was granted temporary registration by EPA
to use ferriamicide as a mound treatment
until July 30, 1978. Before a renewal was
submitted, chlordecone (Kepone) was found
in shelf samples of ferriamicide (Metcalf
1982, Appendix C). Chlordecone, an ana-
logue of mirex, had been shown through the
Hopewell, Virginia, episode to be highly
toxic to humans and animals as a delayed
neurotoxin, an estrogen, and a carcinogen.
PESTICIDE REGISTRATION
The responsibility for pesticide registra-
tion rests with the EPA whose registration
guidelines require that extensive toxicologi-
cal and environmental studies be conducted
before registration can be granted.
Detailed evaluations of these studies are
made by scientists in the Office of Pesticide
Programs (a division of EPA). Although
under the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA), registrants must
demonstrate the safety of their products,
ultimately, EPA bears the burden of deter-
mining the safety of a pesticide.
EPA also conducts risk assessments to
determine the likely risks of pesticide use.
In addition to the toxicology of the pesti-
cide, these assessments consider human and
environmental exposure, i.e. actual use
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78
practices, human activities at treated sites,
and possible absorption of residues. These
requirements are discussed in more detail by
Severn (1982, Appendix F).
Little information has been available on
the exposure of applicators or the general
public to pesticides for IF A control. While
methods to measure direct exposure from
other types of pesticide use have been avail-
able, field measurements of exposure to bait
formulations has not been conducted. As
more chemicals come before EPA for regis-
tration for IFA control, such measurements
will need to be conducted (Nigg 1982,
Appendix G).
DEVELOPMENT OF NEW INSECTICIDES
The Panel has surveyed the range of
insecticides currently registered for IFA
control as well as those under immediate
development. The Agricultural Chemical
Industry responded wholeheartedly to our
request for information on the range of
properties, uses, and performance that we
judged as esssential to evaluate the environ-
mental toxicology of each insecicide, i.e.:
1) chemical name and structure,
2) chemical and physical properties, in-
cluding melting point, vapor pressure,
water solubility, and octanol/H0O
It
partition coefficient,
3) metabolic and environmental degra-
dative fate and pathways, soil persis-
tence, etc.,
4) acute and chronic toxicity,
5) possible mutagenicity, carcinogeni-
city, teratogenicity,
6) wildlife toxicity and hazard,
7) use patterns, and
8) proposed label directions.
This information is appended in data
sheets dealing with (a) mound drenches, (b)
bait toxicants, and (c) insect growth regula-
tors. The properties, toxicological evalua-
tions, and uses of all the chemicals studied
by the Panel are summarized and presented
in Appendix I.
As a result of this approach and thanks
to the excellent cooperation of Drs. Clif-
ford Lofgren, D. F. Williams and W. A.
Banks of the USDA, we can report that
there is a considerable array of insecticides
that probably can be recommended and uti-
lized with some confidence in direct ap-
plication to IFA mounds by homeowners,
licensed pest control operators, and local,
state, and federal authorities.
Bait Toxicants
Several new insecticides have either
conditional or pending registration with EPA
as ingredients of IFA baits. These promise
effective IFA control at dosages ranging
from 1 to 10 grams per acre, are generally
biodegradable, have favorable selectivity,
and low hazards to wildlife. It seems prob-
able that they will be used in a variety of
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79
IPM efforts (see Appendix I, bait toxicants).
Insect Growth Regulators
Four "insect growth regulators" (IGR)
are under development for IF A control (see
Appendix I, insect growth regulators).
These offer considerable promise for oblit-
erating colonies by affecting development
and reproduction. These IGR's are of very
low toxicity to humans and other verte-
brates and are effective at 2 to 20 grams
per acre in bait formulations. These new
chemicals offer opportunities for new and
innovative IF A control by householders,
PCO's, and governmental agencies.
In using these new chemicals for IFA
management, consideration needs to be
given to the range of use: direct mound
treatments, broadcast (ground) bait treat-
ments, and aerial bait applications. The
array of chemicals now registered or pend-
ing registration for IFA management per-
mits a significant choice of alternatives.
However, these chemicals must be evalu-
ated carefully for their capacity to adverse-
ly affect the environment and population
dynamics of target, non-target, and other
invertebrates in the IFA ecosystem. Their
cost effectiveness and potential for resur-
gence by IFA also must be evaluated.
More than 20 years of study in the
"school of hard knocks" have been expended
in learning about the environmental toxi-
cology of mirex and its distribution through-
out the human environment. The magnitude
of the IFA problem and the need for
developing more optimal insecticidal strate-
gies for its control and management dic-
tates that this rate of accumulation of
knowledge about environmental toxicology
is woefully inadequate to deal with the
development of bait programs incorporating
entirely new types of toxicants and insect
growth regulators. Modern systems analysis
and computer technology have the simula-
tive capacity to incorporate such param-
eters as IFA density, rate of application,
rate of effectiveness, effects of competing
organisms, chemical properties such as
water solubility, partition coefficient, rates
of photolysis, and biodegradability, bioac-
cumulation potential, etc. into predictive
models that will avoid environmental mis-
takes or irretrievable environmental dam-
age. Greater emphasis and research needs
to be directed into the development of com-
puter simulations for IFA management.
CONCLUSION
The historical evidence shows that sim-
plistic control and widescale eradication
programs for the IFA are ineffective. It
seems that the best strategy is to develop a
variety of compounds. Several improved
toxicants for bait formulations now have
either conditional registration or are pend-
ing registration. These substances promise
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80
effective IF A control with low hazard to
wildlife. Additionally, four insect growth
regulators are being developed for possible
use on IF A. Perhaps these compounds can
be incorporated into an integrated plan to
manage the IF A.
RECOMMENDATIONS
1. An epidemiological study should be con-
ducted of IF A morbidity in typical rural
and urban situations. (A preliminary
discussion with epidemiologists at the
Center for Disease Control has indicated
that a study is feasible.) Such a study
could lead to the development of an
action threshold for initiating commun-
ity or areawide control programs.
2. A reliable correlation should be estab-
lished between IFA densities and inci-
dence of morbidity in a variety of eco-
logical situations. There is still a great
deal of uncertainty about the pharmaco-
logical and physiological effects of IFA
effects and IFA stings.
3. Toxicological studies should be under-
taken on the properties of the dialkylpip-
eridine alkaloids in IFA venom.
4. Research should be conducted on the
chemistry of IFA natural products and
their potential role as population regula-
tors. Toxicological studies on these
compounds should be implemented simul-
taneously.
5. The cost effectiveness, environmental
impact, and potential for IFA resurgence
under the various control options should
be considered. Using all chemicals
against the IFA may have extrinsic and
intrinsic effects on other ant species and
on a variety of non-target species in the
treatment area.
6. New insecticides and insect growth regu-
lators should be evaluated for their cap-
acity to adversely affect the environ-
mental toxicology and population dynam-
ics of the complex of target and non-
target insects and other vertebrates.
Particular attention should be given to
the potential for IFA resurgence
7. Computer simulations need to be devel-
oped for IFA pest management methods
(Wood 1982, Appendix H). Realistic
models dealing with the environmental
toxicology of IFA abatement procedures
can be expanded into overall IFA mange-
ment and decision-making models by in-
corporating such key features and tech-
nologies as:
a) new pesticide formulation effective-
ness,
b) local area applications mapping,
c) local area environmental effects,
d) site specific and aggregated applica-
tion costs,
e) aggregate area benefit assessments,
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81
f) interactive information and situation
displays, and
g) distributed information system
demonstrations.
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PANEL V
MANAGEMENT OF ESTABLISHED VS. INTRODUCED PESTS
Harold T. Reynolds, Chairman
University of California, Riverside
Roy Clark, Reporter, EPA
Atlanta, Georgia
Gordon Frankie
University of California, Berkeley
Frank E. Gilstrap
Texas A &. M University
Phillip J. Mammon
Texas A &. M University
Marcos Kogan
University of Rlinois
Edward H. Smith
Cornell University
Donald E. Weidhaas, USDA-ARS
Gainesville, Florida
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INTRODUCTION
There are literally thousands of exotic
pest species that could thrive in the United
States. Likewise, many species already ex-
isting in this country could extend their
range if transported into areas with com-
patible environmental parameters. Typical
examples of such introductions are the
movement of the pink bollworm into Ari-
zona and California cotton production areas,
the anticipated westward movement of the
IF A, and the gypsy moth. Introductions of
fruit fly species from foreign sources can be
expected to occur periodically. These ex-
amples typify introductions that can be ex-
pected to occur with a host of species with
potentially serious problems resulting.
Authorities must remain alert to such po-
tential introductions and prevent them if
possible. The rapid transportation provided
by jet aircraft and the enormous numbers of
people travelling have vastly complicated
existing quarantine systems. Quarantines
are the first line of defense against intro-
duction, and their degree of effectiveness
should be continually evaluated and
strengthened.
The importance of early detection of
introduced pest populations cannot be over-
emphasized. Detection before such popula-
tions adapt to their new environment or
prior to population explosion makes the
problem of coping with them much simpler.
Eradication, for example, may be feasible if
detection is early, but eradication may be
impossible at a later time. Improved detec-
tion methods should be sought continually
and adopted when appropriate. Survey and
monitoring techniques should be simple, re-
latively inexpensive, and effective. Pro-
grams to provide early detection are operat-
ing; however, their effectiveness is less than
desirable and enhancement is clearly
needed.
[Appendices M through P provide detailed
information on the concept and practice of
eradication and prerequisites (Appendix M:
Smith); biological control, an historic over-
view and as it is applied to the IF A (Appen-
dix N: Gilstrap); examples of eradication
programs and the population dynamics of
introduced species (Appendix O: Kogan); and
the special problems of introduced species
in urban environments (Appendix P: Frankie
et al.)J
INTRODUCED PESTS IN ESTABLISHED
ECOSYSTEMS
Despite the large numbers of potential
pests confiscated at quarantine points, pest
species continue to invade and become es-
tablished in the U.S. Often these pests
cause major losses to agricultural produc-
tion. They also can detrimentally affect
environmental quality, human health, and
the aesthetic value of plants. Losses from
82
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83
these pests are sometimes catastrophic, and
yet attempts to cope with such acute prob-
lems frequently result in ecological upsets
and associated problems.
Human commerce has magnified the
flow of arthropods across geographic barri-
ers. Although measurement of the rates of
movement in terms of numbers of species
and of individuals per species is difficult,
APHIS reports on interceptions may be a
valuable data base for an analysis of these
events. (For example, in a one-year period
(1978 to 1979), 14,002 insect plant pests
were intercepted at quarantine points.)
Some species that cross geographic barriers
successfully establish themselves in a re-
gion. Many more species do not succeed
probably due to hazards in the new region,
such as (1) the absence of adequate hosts,
(2) inhospitable climatic conditions, (3) pre-
dation by general native predators, and (4)
genetic degeneration due to excessive in-
breeding because of the narrow gene pool of
the few colonizers.
Agricultural Environments
Many introduced pests have been detect-
ed approximately 10 to 15 years after the
presumed date of immigration. After this
initial, latent phase, the pest population,
free of effective natural enemies and better
adapted to the new environmental condi-
tions, explodes. It is in the beginning of the
explosive phase that the pest most often is
detected and control actions are contem-
plated. During the explosive phase, IPM
programs in agricultural ecosystems are dis-
rupted, because researchers, extension
specialists, the pesticide industry, and pro-
ducers must redirect their efforts, thus
hindering long-term programs (see Appendix
N).
Many introduced species that go through
this explosive phase are extremely difficult
to eradicate. They expand their geographic
range and, after a time, stabilize and are
increasingly affected by the regulating
forces of the new environment. Sometimes
the stabilized population exceeds tolerable
levels. Such introduced pests often become
key pests of a crop, either as an additional
key pest, by replacing previously-established
key pests, or by assuming key pest status if
the crop was previously free of key pests.
This status means that inadequate popula-
tion regulation exists and control procedures
must be applied on a recurrent basis. Often
this disrupts other pest populations that
were previously under dynamic equilibrium
and kept in check by natural enemies. The
boll weevil in cotton is a classic example
and dramatically illustrates this phenome-
non. Among the many consequences of the
boll weevil invasion many years ago has
been the rise of Heliothis to its current
position of prominence in cotton ecosystems
throughout the cotton belt, largely because
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84
attempts to control the boll weevil, mainly
with insecticides, have so destroyed the
natural biotic components in the cotton en-
vironment that Heliothis populations are re-
leased from effective population regulation.
Public awareness of newly-introduced
pests usually occurs during the explosive
phase of establishment. The public often
overreacts, even panics, and pressures au-
thorities to "act." If the energies of the
public outcry are directed correctly, they
may help generate the necessary funds to
support the coordinated efforts that are
required to eradicate, contain, or manage
the pest, e.g. the imported crucifer weevil
in Illinois.
The examples of the European corn bor-
er, cereal leaf beetle, and several other
introduced agricultural pests suggest that it
is virtually impossible to detect these pests
during the early phase of establishment.
Quite possibly, this difficulty is one of the
reasons why the eradication programs for
these pests failed.
Urban Environments
In contrast to agricultural environments,
new pests introduced into urban environ-
ments often exploit previously unoccupied
niches, mostly because so many actual and
potential niches are extant in urban areas.
This in turn is related to the urbanization
process, which includes the introduction of a
wide variety of exotic plant species and the
establishment of new structures and the
renovation of old ones. Thus, one may
expect most newly-introduced species to oc-
cur in urban environments. In some cases,
these pests establish in indoor habitats that
are geographically far beyond their usual
physiological limits (e.g., pests that invade
indoor habitats in cold climates).
Because many species introduced into
the urban environment cause aesthetic
rather than economic loss, they may be
assimilated with little overall impact on
urbanites (witness the introduction of a new
domiciliary cockroach species or a new a-
phid species on an ornamental plant—organ-
isms that are already represented in most
urban areas). On the other hand, when the
introduced species are considered to be of
economic or public health importance, the
impact may be substantial, especially from
a social standpoint.
Frankie et al. (Appendix O) postulates
that urban centers are and will remain the
areas of first discovery for most exotic
pests, mainly because urban areas are the
major points of entry for goods and people
by air or sea. Once new pests are estab-
lished, people may exacerbate their pest
problems through their everyday activities,
for example, through their intra- and inter-
city movements where they unknowingly
transport pests to uninfested areas (i.e. gyp-
sy moths, IF A, bark beetles, Dutch FJm
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85
disease, Japanese beetles). In fact, such
activity could be the route of first introduc-
tion. Once arrived, pests may interact with
people and essentially become more of a
"people problem" than a strict biological
problem due to the way people perceive and
respond to these pests.
People can further increase their pest
problems when they muster enough political
power to determine or greatly influence the
type of control programs to be used against
the pests. Often these are not the most
effective programs and thus represent com-
promises that are strongly tempered by
social and political considerations. Results
usually are unnecessarily expensive and en-
vironmentally detrimental. Some urbanites
cooperate in management programs, but
many are apathetic. This may be related to
the aesthetic nature of the problem rather
than to economic or public health concerns.
Other Environments
Newly-introduced pests can economical-
ly impact animal production. In the 1880's,
the horn fly spread throughout the country;
control costs and economic losses due to
reduced animal production were great. The
screw worm, native to the southwest U.S.
and introduced into southeast U.S. in the
1930's, annually caused losses and control
costs in the millions of dollars, until it was
essentially eliminated. The face fly, anoth-
er economically important introduction, also
affected animal production. These types of
introductions have impact because of the
insect itself. Introductions of diseases pre-
sent a different problem. For example, the
mosquito, Aedes aegypti, although a very
old introduction, exists and is a potential
vector of dengue fever which is currently
present in the Caribbean area and Mexico.
Other diseases of humans and animals could
be introduced because the vectors of these
diseases are present in the U.S.
MANAGEMENT METHODS FOR
INTRODUCED PESTS
Research Needs
There is an historic and substantial gap
between the "action" of regulatory agencies
charged with conducting eradication pro-
grams and research scientists who have gen-
erated the information and technology used
for various control tactics. This point was
made extremely well by W. L. Brown, Jr.,
who over 20 years ago reviewed four, area-
wide, mass insect control programs, of
which one was the IF A. Brown (1961) was
highly critical of the programs because re-
search was not integrally involved.
Every mass control campaign should
have an adequate research program
functioning as far ahead as possible
before control operations get under-
way. The control work should be
guided by the research and not the
reverse, and every campaign should
be reevaluated frequently to see if a
need for it continues.
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The newly-detected, introduced pest
presents a rather unique set of problems.
Not only must decisions be made quickly
regarding tactics and scope of the program,
but these decisions are usually based on
limited biological information and no cer-
tainty of the pest's rate of success or distri-
butional increase in the new environment.
Furthermore, recent decisions, made by a
small group of state and/or federal regula-
tory personnel, have often opted for eradi-
cation via pesticide application. Eradica-
tion programs are not always successful, and
when they are not, research to develop or
implement alternative courses of action is
generally inadequately organized or funded.
This delay in research activity is unneces-
sary and unwise, as area-wide programs are
increasingly subject to public focus and par-
ticipation. Such public focus should be used
to initiate research into short and long term
needs and studies on alternative manage-
ment tactics.
The short-term management research
needs could include advice from a panel of
appropriate scientists regarding pesticide
options, formulations, modes and rates of
application, and, perhaps most importantly,
obtaining and interpreting efficacy data.
The short-term research panel would also
promote collection and interpretation of lit-
erature; considerations regarding best meth-
ods and materials for detection; and sugges-
tions for kinds of approaches to, and suit-
able scientists for, pressing research needs.
Short-term management research should al-
so continually evaluate program objectives
and actions. The formal incorporation of
research in an advisory role to eradication
programs (1) would be relatively inexpen-
sive, (2) would allow early development of
research needs on a commodity and area-
wide basis, (3) should substantially improve
prospects for successful eradication, and (4)
would assure the affected public of an or-
ganized transition into other management
tactics.
Given that an eradication program
evolves into one only of containment, the
original short-term advisory panel should
become involved in developing the probable
changes in longer-term tactics for regular
commodity protection (e.g., changes in rec-
ommendations for IPM) and production.
These changes would minimize the immedi-
ate impact of the pest on affected crops and
existing IPM programs. The panel should
recommend and promote new research needs
where required to develop potential crop
protection options.
Biological Control
Classical biological control is more like-
ly to succeed for introduced pests, and can
permanently regulate populations. Because
of this, preliminary studies on biological
control, possibly funded by the eradication
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87
program, should be initiated at an early date
and should be evaluated in the event eradi-
cation cannot be undertaken or fails. These
studies should be separate from objectives
of the short-term research panel and should
function concurrent with early eradication
attempts. The research panel should include
a taxonomist of parasitic Hymenoptera
and/or Diptera as appropriate, an insect
pathologist, a quantitative ecologist, and a
specialist with formal training and experi-
ence in classical biological control. Initially
the panel would evaluate the prospects for
successful biological control, including (1)
known natural enemies and their biologies
and distribution, (2) probable host plants and
any existing host-plant resistance of the
pest in the aboriginal home, (3) potential
foreign exploration problems and needs, and
(4) the ecosystem of the pest in the abori-
ginal home.
The panel's role and activities would
increase if the eradication program looked
like it was failing. Foreign studies would be
initiated to begin collecting and testing the
pest's natural enemies. If the eradication
definitely was not working, funding would
shift to biological control and eradication
tactics towards containment using control
methods compatible with establishing new
natural enemies.
Eradication
The term "eradication" as used here
means to eliminate a pest population from a
specified area. Presumably, having elimi-
nated the pest population, the area would
remain free of the pest until reentry by
mobility of the species or introduction
through human activity. Ecologically, erad-
ication involves removing a species from a
niche. This action sometimes opens the
niche to one or more other species that may
be economically significant. As eradication
is normally directed against newly-intro-
duced species, the steps involved in pest
establishment and stabilization are of parti-
cular interest. The population dynamics of
newly-introduced species usually reflect
three phases: (Phase 1) establishment in the
niche, (Phase 2) rapid population growth,
and (Phase 3) stabilization from the actions
of biological constraints.
During phase 1, pests are most vulner-
able to eradication efforts; therefore, early
detection is necessary. Once the introduced
pest advances to phases 2 and 3, its unique-
ness and vulnerability changes and becomes
similar1 to the problem posed by indigenous
pests.
Biology, economics, and politics influ-
ence eradication. The political factors are
particularly complex because they involve
different constituencies and political enti-
ties and agencies having conflicting objec-
tives and needs. The case histories of
eradication programs are widely variable,
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88
panging from highly effective programs to
abject failures. Based on experience ac-
quired over a period dating from the earliest
eradication programs in the late 1800's, a
list of prerequisites needed for programs to
have a reasonable probability for success
can be drawn. This list includes the follow-
ing:
1. High socioeconomic importance of
the pest. The eradication strategy gen-
erally, but not always, involves a com-
prehensive research program to develop
the needed technology. This phase is
followed by a complex phase involving
extensive control programs. Such major
effort should be reserved for insect pests
of high socioeconomic importance.
2. Specific advantages of eradication
over suppression. Unless there is a clear
advantage to eradication over suppres-
sion, eradication is not justified assum-
ing effective technology and modest
economic and environmental costs for
suppression programs. Recent advances
in controlling cotton pests, for example,
requires a reassessment of the eradica-
tion option.
3. Effective monitoring technology. Ef-
fective technology for monitoring pest
populations must be available. Without
such technology, it is impossible to de-
termine the area infested by the pest or
the results of treatment. Recent ad-
vances in pheromone chemistry and
technology offer promise here.
4. Effective control technology. In
most cases, eradication efforts will in-
volve a combination of measures. The
potential effectiveness of the total ef-
fort must be demonstrated before under-
taking eradication, particularly in large
expensive programs. This poses special
problems because of the difficulty of
interpolating from small, preliminary
tests to large area tests. The paucity of
data on effectiveness of IF A treatments,
for example, was a problem of early
eradication efforts.
5. Environmentally acceptable pro-
grams. The impact of control programs
on the environment must be assessed
before launching eradication programs.
This poses a difficult problem because of
the time element involved in making
preliminary determinations.
6. Favorable logistical odds. Large-
scale application programs should be
simple or the element of human error is
likely to cause serious setbacks. The
accuracy of aerial application or the
thoroughness of scouting for infested ar-
eas are the kinds of operations alluded to
here. The likelihood of failure increases
as the size of the infested area in-
creases. Similarly, the longer the pest
has been established, the better it adapts
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89
to its environment.
7. Adequate funding to sustain pro-
grams. Realistic estimates of costs of-
ten have not been established before
programs are begun. Undertaking pro-
grams that have open-ended budgets will
likely place the program in jeopardy as
funding may be dropped or credibility
may be lost because of excessive costs.
The WHO program on malaria eradica-
tion illustrates the impact of inadequate
funding, although other major flaws ex-
isted in the overall design.
8. Adequate administrative resources to
sustain programs. A high level of admin-
istrative competence is required to coor-
dinate an eradication program. This
essential input is more difficult to pro-
vide when programs extend across state
and national boundaries. Good science
and sound scientific advice should be the
foundation for administrative decisions
early in the planning period.
9. Favorable socioecological conditions.
The success of eradication programs may
depend on the cooperation and active
participation of area residents. It is
essential that a high level of public sup-
port is assured so that regulatory author-
ity can be invoked to take required mea-
sures with minimal impediments.
10. Favorable cost/benefit relationships.
The great appeal to eradication pro-
grams is that through the initial "capital
investment" phase the pests will be elim-
inated thereby avoiding the recurring
costs of control programs. These cost/-
benefit relationships must be calculated
realistically to avoid disillusionment.
No list of prerequisites can assure suc-
cess of eradication programs. An element
of risk will always remain. Eradication
should be a viable option subject to rigorous
assessments to determine its appropriate-
ness. The ten points listed above should
help in putting this decision-making process
on a scientific basis and in improving biolo-
gical, social, environmental, and economical
acceptance.
RECOMMENDATIONS
1. Each new eradication program should in-
clude concurrent research to identify the
pest's probable aboriginal home; the ex-
isting biological restraints, particularly
the existence and taxonomy of potential
natural enemies; the known host plants;
and the political mechanisms needed in
the foreign country to implement pro-
grams.
2. The program ideally should consist of a
taxonomist specialized in the pest group,
a taxonomist of parasitic Hymenoptera
and/or Diptera as appropriate, an insect
pathologist, a quantitative ecologist, and
a specialist with formal training in biolo-
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90
gical control.
3. The following considerations should be
made to guide decisions on large eradi-
cation programs:
Assess and demonstrate the effective-
ness of eradication tactics;
Assess the socioeconomic importance of
the pest;
Evaluate the advantages of eradication
over other control strategies;
Determine the availability of effective
monitoring systems;
Develop concurrently effective control
technologies;
Assess environmental acceptability of
the program;
Assess the availability of favorable lo-
gistical odds;
Assure availability of adequate funding
to sustain such programs;
Assure availability of adequate admini-
strative resources to sustain the pro-
gram;
Assure adequate communication with the
public affected by the program;
Evaluate the probability of a favorable
cost/benefit relation of the program.
4. The effectiveness of existing quarantine
and inspection procedures (international
and between states) that deal with
movement of travelers and products be
evaluated. Effectiveness needs to be
enhanced wherever possible, including
new educational materials that notify
departing travelers of kinds of items
restricted on re-entry and the rationale
behind such restrictions.
5. Appropriate educational materials should
be prepared for informing the public,
particularly in the vicinity of ports of
exit and entry, about the identification,
biology and importance of introduced
pests. This information should be avail-
able to urban and non-urban residents.
6. Aggressive efforts should be made by
responsible and informed officers to pre-
pare and deliver education materials to
the public and public officials explaining
the importance of introduced pests and
why efforts to manage them, although an
inconvenience, are imperative.
7. Students should be given information on
the importance of introduced pest prob-
lems and in the philosophies, methodolo-
gies, and need for eradication as one
option to cope with such problems.
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PANEL VI
IFA MANAGEMENT STRATEGIES
Richard J. Saner, Chairman
University of Minnesota
Homer L. Collins, Reporter, USDA-APHIS
Gulfport, Mississippi
George Allen, USD A
Washington, D.C,
Doug Campt, EPA
Washington, D.C.
T. Don Canerday
University of Georgia
George Larocca, EPA
Washington, D.C.
Clifford Lofgren, USDA-ARS
Gainesville, Florida
Gene Reagan
Louisiana State University
D.L. Shankland
University of Florida
Mark Trostle
Texas Department of Agriculture
Walter R. Tschinkel
Florida State University
S.B. Vinson
Texas A &. M University
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INTRODUCTION
Evidence shows that the red imported
fire ant, Solenopsis invicta, cannot !>e eradi-
cated from the U*S.; therefore, there will be
a continuing need for programs to manage
this pest. The actual pest status of the
imported fire ant (IFA) is yet undetermined;
however, the fact that it is a pest is irrefut-
able, although much more needs to be known
about its public health, economic, and nui-
sance impact in various environments. The
IFA is a human or "people" pest of major
medical importance. Surveys show that 25
to 30% of the persons living in infested
areas are stung at least once each year
(Clemmer and Serfling 1975, Adams and
Lofgren 1981, Yeager 1978). Less well-
defined data suggest that up to 1% of the
persons stung may require medical consulta-
tions (Lofgren and Adams 1982). A survey
by physicians in Jacksonville, Florida, esti-
mated that 3.8 new persons per 100,000
population develop a hypersensitivity reac-
tion each year (Rhoades et al. 1977). This
figure translates to about 1,500 new cases
per year over the IFA-infested area. Its
importance as a pest of pastures, livestock,
and crops is less defined. Although the
possibility of crop losses exists, especially in
soybeans, the IFA has been shown to be a
beneficial predator in several agricultural
ecosystems (Oliver et al. 1979).
The problem of controlling the IFA is
particularly difficult because the ant occu-
pies a wide range of habitats and is an
extremely effective colonizing species. Pri-
mary objectives of any management pro-
gram for IFA are to maintain the species at
a density level low enough to reduce its (1)
public health impact by minimizing contact
with humans and (2) impact on farming
operations and crop production. Fulfilling
these objectives requires strong suppression
of IFA in areas where there is a high proba-
bility of human-ant contact and mainten-
ance of IFA populations in other areas at
levels that do not cause nuisance or eco-
nomic problems.
As the only available tactic for strong
temporary suppression of IFA, chemical
controls (see Appendix K) will have to be
used periodically (usually once a year) to
eliminate new or re-infestations. Biological
or cultural controls are desirable; however,
no biocontrol techniques are available and
probably will not be for at least five to ten
years. Emphasis needs to be placed on
research to discover biological and other
non-chemical approaches to control. The
most desirable long-range strategy for any
IFA management program should be a com-
bination of chemical and non-chemical con-
trols where IFA cannot be tolerated and
biological controls or integrated pest man-
i
agement where low-level populations can be
tolerated.
91
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92
In some habitats the IF A is a key bene-
ficial insect. In Louisiana sugarcane fields,
the IF A is the most important beneficial of
the biological control component which re-
duces sugarcane borer populations by 25%
(Reagan 1982). It is also an important
predator in Louisiana soybean fields (Stam
1978). The IF A has drastically reduced tick
populations in Louisiana and has been asso-
ciated with a decline in tularemia rij
(Burns and Melancon 1977, Oliver et al.
1979). The IFA also preys on horn flies and
other pests in pastures (Howard and Oliver
1978 & 1979). However, the IFA also tend
disease-carrying aphids and kill ground-nest-
ing bees (Vinson, unpublished).
CURRENT TECHNOLOGY USE IN
VARIOUS HABITATS
The IFA occupies a variety of habitats in
urban, suburban, and rural situations. The
pest status of the IFA in each of these
habitats differs because the ant causes
varying types and degrees of problems and,
in a few cases, is beneficial. Because of
these disparities, certain questions must be
considered for each habitat where control is
needed:
1. What is the nature and magnitude of
the problem?
2. What measures are available to solve
the problem?
3. Who makes the decision to take
action and what action should be
taken?
4. Who implements the action?
These questions imply that the decision-
maker will bear the cost of the action.
Homes: Urban and Rural
Generally, the problem in this habitat is
human exposure, especially that of small
children and hypersensitive individuals, but
it may also include aesthetic appearance of
lawn and garden. The tolerance for either
problem is likely to be very low, with treat-
ment costs probably not a determining fac-
tor.
Several pesticides are labeled for home-
owner use as mound drenches; one is labeled
as a bait for mound or broadcast treatment
(see Appendix K). In addition, homeowners
can drench mounds with hot water if only a
few to several mounds are to be controlled;
however, this method is minimally effective
and requires multiple applications.
Ultimately, the decision to treat rests
with the homeowner or occupant, if a lessee
or renter has authority to make such deci-
sions for the owner. If control action is
decided on, the responsible person has the
freedom, because of the availability of
materials registered for home use, to imple-
ment the action or to hire a pest control
operator or other agent. In some instances,
government control programs are necessary
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to give relief to homeowners on limited
incomes.
Public and Private Lands
Because the accessibility and activities
in these areas makes contact with the IFA
highly probable, human exposure is generally
the main problem and, perhaps, aesthetics.
Sites of concern include school grounds, play
grounds, parks, cemeteries, median strips or
borders of streets and roads, municipal golf
courses, power line rights-of-way and ease-
ments, grounds of municipal facilities of one
type or another, rest areas, levees, etc. In
the case of levees, tunneling by the IFA
could cause water seepage. In contrast to
homesites, public exposure includes children
in schools, citizens utilizing recreational
and other areas, and employees of various
organizations having stewardship over the
land. Questions of legal liability of the
respective controlling authority for harm to
persons by IFA stings may arise and could be
a factor in determining tolerance levels.
All of the EPA-approved control mea-
sures available to the homeowner are avail-
able for public lands. If large areas are
involved (more than a few acres), individual
mound treatments with drenches are im-
practical; however, baits may be used either
as individual mound treatments or broadcast
with ground or aerial equipment.
In every case cited above, some identifi-
able agent has stewardship and authority
over the land concerned. School boards,
park boards, county boards, city councils,
for example, generally make decisions on
the management of the land within their
commission—including pest control deci-
sions. Decisions may be based on concerns
of the patrons; therefore, the tolerance for
IFA may vary with each case. There may,
for example, be a much lower tolerance set
for IFA on school playgrounds than for IFA
in median strips. Legal liability may be
another factor affecting tolerance levels.
In any event, the decision to take action will
be jointly considered by the legally-account-
able authorities, if not also by the patrons.
The decision may be tempered by the avail-
ability of funds to support the action (e.g.,
the tolerance threshold may be partly deter-
mined by the cost of treatments). This is
more likely to be an issue on public lands
than on homesites.
Depending on fiscal, manpower, and
equipment resources of the agency
concerned, a control measure may be imple-
mented by the agency, or contracted
through commercial operators. Private golf
courses constitute a special case. Usually,
however, golf courses have professional
managers authorized to take the necessary
action to control IFA, or at least to seek
approval to do so from the governing board
or other governing body of the course. IFA
management falls under the course pest
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94
management program which usually exists
at some level of dependency on the
resources and standards of the particular
course. Managers generally have ready
access to current pest control information
through university extension, USDA, or
research sources or from commercial con-
sultants or industry.
Agricultural Environments
The most significant problem when IFA
inhabit agricultural environments involves
human exposure—the nuisance, discomfort,
and potential health hazard associated with
the ants and their sting. Potential problems
exist with damage to harvesting equipment
by IFA mounds and the impact on crop
yields. Some data reveal that stands and
yield of soybeans may be substantially
reduced by IFA (Lofgren and Adams 1981,
Adams and Lofgren 1982, Apperson and
Powell 1982). Conversely, the literature
reports that IFA are good predators, especi-
ally against the sugarcane borer (Reagan et
al. 1982).
Currently, few alternatives are available
to control IFA in agricultural environments.
Amdro* bait is registered for application to
pastures, range grass, lawns, turf, and non-
agricultural lands, and may be available for
cropland in 1983. On small acreage or in
light infestations, Amdro can be applied to
individual mounds. Another option includes
broadcast treatment with ground equip-
ment—a procedure more adapted to inter-
mediate-size parcels of land. Aerial appli-
cation is perhaps best suited for large acre-
ages. For long-term control, yearly applica-
tions may be required. Some mechanical
options, such as mound leveling in the win-
ter, provide limited mound reduction and
ant suppression.
The landowner/attendant should be the
primary person in assessing the problem and
selecting a course of action. This does not
assume that various governmental units may
or may not take the responsibility for area
suppression programs when acceptable man-
agement tools and technology are available.
Regulatory Control/Quarantine
Artificial spread or movement of the
IFA into non-infested areas of the U.S.
through interstate shipment of items such as
grass sod and nursery plants is well docu-
mented. Federal Quarantine 301-81, in-
voked May 6, 1958, was designed to prevent
this occurrence. Initially dieldrin and hep-
tachlor were used as insecticidal treatments
to certify movement of regulated articles.
Use of these products was discontinued
February 13, 1970, in preference to chlor-
dane. Chlordane was used until December
31, 1979, when the final cancellation order
concerning use of chlorinated hydrocarbon
insecticides for IFA quarantine treatments
became effective. Currently available
chemicals do not fulfill all of the necessary
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95
requirements for good quarantine treat-
ments.
Dursban Fa-5 is registered to treat pot-
ting soils where plants are grown. However,
due to phytotoxicity problems, Dow Chemi-
cal (the registrant) voluntarily withdrew this
product from the market. Dursban 4E and
2E are registered as a root-dip treatment
for balled and burlapped plants, but this
procedure is highly disfavored by growers
due to the cost and labor required for imple-
mentation. Currently, no chemical treat-
ments are registered to treat grass sod.
Statutory authority promulgated under
two Acts of Congress (Plant Quarantine Act
of August 20, 1912, and Organic Act of the
Department of Agriculture September 21,
1944) designate the U.S. Department of
Agriculture, Animal and Plant Health In-
spection Service, Plant Protection and
Quarantine as the responsible organization
to issue regulations governing movement of
articles capable of spreading the IF A.
Growers implement USDA/APHIS/PPQ-
approved treatments as specified in admini-
stratively approved control manuals (805-
25.000). These treatments are supervised by
federal (or in some cases state) quarantine
inspectors.
Other
In addition to the above problems, IFA
increasingly are reported as damaging air
conditioners, water well relays, ground elec-
tric transformers, telephone junction boxes,
airport lights, and underground sprinklers.
This has caused inconveniences and econom-
ic losses to various commercial businesses.
At this time, other than heptachlor 5%
granular for IFA in telephone junction
boxes, there are no controls specifically for
this situation other than to use the chemi-
cals available for control in the habitats
where these types of equipment are found.
Research is needed on why electrical wiring,
relays, and related equipment attracts IFA
and causes them to feed on and damage
these items.
CURRENT TECHNOLOGY AND GAPS IN
CURRENT RESEARCH
Existing, But Unavailable Tools
Several chemicals presently exist but are
not available, at least for some uses, as IFA
control tools for the following reasons:
Amdro is presently registered for use in
pastures, rangeland, and non-agricultural
areas. American Cyanamid, the registrant,
has requested EPA approval for use of this
product on all croplands. Data supporting
use of this expanded label has been submit-
ted to EPA (May 1982). The EPA is present-
ly evaluating this data.
Mirex was previously used in IFA control
programs. When problems of persistence,
bioaccum ulation, and alleged carcinogeni-
city surfaced, EPA cancelled all registra-
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96
tions effective June 30, 1978.
Ferriamicide is presently under consider-
ation by the EPA for registration for IFA
control. Questions concerning the human
and environmental impact of this compound
have been addressed under Panel IV of this
symposium. Final determination on regis-
tration will be made by the EPA.
Chlordane was previously used in IFA
control programs and in regulatory treat-
ments. Studies alleging that chlordane was
a carcinogen resulted in cancellation of
most uses by the EPA on March 6, 1978.
Use of chlordane for regulatory treatments
was phased out December 31, 1979.
Dursban (chlorphyrifos) was previously
registered as a quarantine treatment to nur-
sery potting media and bench soils. How-
ever, phytotoxicity problems resulted in vol-
untary withdrawal by Dow Chemical Com-
pany pending further research to develop a
dose rate that would alleviate phytotoxicity.
Lindane is currently under investigation
for broad spectrum quarantine treatment.
Preliminary data indicate that it will be
satisfactory as a potting soil and root dip
treatment. Results on grass, sod and field-
grown ornamentals are incomplete.
Aldrin, which is presently registered for
termite control, can be used as a root dip
treatment for IFA control; however, no pro-
ducts are presently labeled for this use.
When aldrin/dieldrin was cancelled in 1974,
one of the exempted uses was the dipping of
roots and tops of non-food plants. USDA
indicates that this procedure (root dip) is
not widely accepted by growers due to the
cost and labor required for implementation.
Pesticides registered for other uses are
presently pending EPA approval for IFA
control. These chemicals are targeted
mainly for individual mound treatments and
are to be used primarily on non-agricultural
lands by professionals and homeowners. The
present group includes: methyl chloroform
(1,1,1-trichloroethane), Imidan, Resmethrin,
rotenone, lindane and Methylenebis (thiocy-
anate).
Current technology
1. Chemical Control
Bait Toxicants: The USDA has
screened approximately 7,500 chemicals
and formulations as toxic bait for the
IFA (Williamson 1982). These tests are
designed to select chemicals that have a
delayed toxic reaction, i.e., allow worker
ants to distribute the bait to other work-
ers and the queen. Only two compounds
have been registered by EPA, but regis-
tration of the most effective chemical
(mirex) was withdrawn in December,
1977. In August of 1980, Amdro was
conditionally registered for public use by
EPA for mound or broadcast application
to non-agricultural lands, lawns, turf,
pastures, and range grass. Another
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active toxicant is being developed by the
Eli Lilly Company and may have condi-
tional registration in 1983. A third com-
pound that acts as a toxicant and repro-
ductive inhibitor is being developed by
Merck and Company and is undergoing
field tests under an EUP.
Evaluation of insecticides for use as
mound drenches or fumigants to control
IF A colonies has accelerated during the
past few years. Several chemicals have
been registered for this purpose (diazi-
non, chlorpyrifos, carbaryl, acephate,
bendiocarb, pyrethrins I and n, and
methyl bromide) and others are being
tested. The problems with mound
drenches are (1) the difficulty in locating
small or hidden mounds, (2) the need for
multiple applications, and (3) the neces-
sity of applying the drench when the ants
are most susceptible. In addition, this
method of fire ant control is applicable
only to very limited areas, urban proper-
ties, and homesites. Research on the
factors and/or procedures needed to en-
hance this method of control are needed.
Insect Growth Regulators: Research
on insect growth regulators (IGR) has
been conducted at Texas A&M Univer-
sity and the USDA (Banks 1982). Most
interest has been expressed in the juve-
nile hormone mimics, although some
research has been conducted on an ex-
perimental chitin-inhibitor. Juvenile
hormone mimics stop development of
immature stages or induce caste shifts
that result in the development of large
numbers of abnormal sexuals.
A bait containing one of these com-
pounds (Stauffer MV-678) has been field
tested in a soybean oil, pregel, defatted
corn-grit bait similar to Amdro. High
concentrations of the compound were
used to completely flood the crops of the
ants. With this approach, a one-time
feeding produced effects on the colony
that lasted up to a year; with MV-678,
75% of treated laboratory colonies died.
A field test with a bait application of
MV-678 at four grams per acre was con-
ducted at Ft. Stewart, Georgia. Appli-
cations were made in the fall and the
spring. Three months after the second
application, 75 to 80% of the colonies
were dead, and almost all remaining
colonies were without brood.
Two other insect growth regulators
(MAAG agrochemical R013-5223 and
Montedison JH 286) are being field
tested. Problems may result from the
need for several applications to provide
adequate control and a lack of specifi-
city to IF A.
Behavioral Chemicals: Behavioral
chemicals (pheromones) are a fruitful
area of research since a complex of
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pheromones regulate colony activity.
Behavioral chemicals offer unique oppor-
tunities to disrupt the IFA's social organ-
ization or affect their behavior in ways
that could lead to their demise. Behav-
ioral chemicals are important in colony
recognition, colony founding, egg laying,
queen recognition, queen acceptance or
tolerance, brood care, food and nest
location, and caste control. Five phero-
mones are under study or have been
isolated and identified (a brood phero-
mone, trail and recruitment pheromone,
feeding stimulant, a queen recognition
pheromone, and a queen dealation-inhibi-
tion pheromone). The trail, queen,
brood, and recognition pheromones could
be used to make toxic baits more attrac-
tive and specific.
Delivery Systems (Formulations and
Application Methods): Methods for
formulating baits for IFA were described
several years ago and are extremely ef-
ficient. However, they must be made
more specific to the IFA. One approach,
other than behavioral chemicals, is a
bait that would allow the use of more
rapidly acting chemicals. Research is
needed (1) to identify other food materi-
als (proteins or carbohydrates) that
would deliver more specific distribution
of bait and toxicant within the colony,
and (2) to discover if bait attractiveness
is influenced by the time of year and
changing food preferences of the IFA.
Methods for applying baits and other
agents in large plot tests have been
studied by APHIS personnel. Although
delivery systems for granular baits are
available for ground and aerial applica-
tion, the technology needs to be further
developed for more efficient and effec-
tive application. If biological control
agents are found, specific delivery sys-
tems will have to be developed to
disperse these agents in the environ-
ment.
2. Biological Control
Pathogens: The search for potential
IFA pathogens was accelerated by the
discovery in the early 1970's of a proto-
zoan infection in fire ants in Brazil.
This organism was found in up to 25% of
the colonies examined, although the de-
gree of infection varied considerably.
One other microsporidian has been de-
tected. Little is known about the epi-
zootiology of either of these organisms.
At least one bacterial pathogen and one
virus have been found in Solenopsis in
Brazil. Because no research station has
been established in South America, the
full potential of pathogens for IFA con-
trol cannot be assessed at this time.
Research on pathogens of the native fire
ant, S. geminata, is being used to
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99
develop methods and procedures for
working with diseases of ants.
Parasites: The most highly studied
parasite of the fire ants is the worker-
less social ant, Solenopsis daguerri. This
ant has been found attacking colonies of
S. richteri, but not S. tnvicta. Research-
ers who have worked with this social
parasite conclude that it would not be
useful for controlling or reducing IFA
populations in the U.S. This is based on
the limited distribution of the parasites
in South America and the difficulty in
transporting the parasites from one site
to another. Species of two other groups
of parasitic insects, chalcid wasps and
phorid flies, are associated with fire
ants. Non-specific parasites such as the
nematode, Neoplectana carpocapsoe, are
under study for treatment of individual
colonies. An up-to-date review of the
status of biological control of IFA is
presented by Jouvenaz et al. (1981).
3. Procurement, Screening and
Evaluation
Developing biological control agents
is a difficult and time-consuming pro-
cess. This is particularly true of patho-
gens. The biggest drawback to progress
in this field has been the lack of a
research station in Brazil from which
researchers could search for biological
control agents. Up to this time, knowl-
edge has been gained through short-term
trips that have lasted from two to six
weeks, which does not provide time for
intensive survey of any particular area
and certainly has not allowed time to
determine the potential usefulness of
any of the organisms that have been
detected thus far. Once money is avail-
able to establish a biological control
station in South America, then the pro-
cess of procurement, screening, and
evaluation of potential agents can pro-
ceed. Provisions, however, must be
made for backup resources within the
U.S. for basic research on the organisms
that are found and for evaluating any
potential detrimental effects of these
organisms to our native fauna and flora.
Physical and Cultural Control
1. Tillage and Cultivation Practices
It has been thought that tillage or
cultivation deterred the establishment of
IFA colonies. More recent observations,
however, question this conclusion, par-
ticularly where these disturbances are
discontinued. For example, IFA com-
monly are found in soybean fields at
densities of 30 to 40 mounds per acre
(Lofgren and Adams 1981). Studies in
sugarcane have demonstrated higher ant
populations where fields that had a dense
growth of broadleaved weeds shading the
roads were cultivated four times rather
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100
than the minimum two times (White
1980). However, thorough weed suppres-
sion in sugarcane possibly restricts gen-
eral insect populations (potential IF A
food supply) and results in up to a 50%
seasonal abundance of IF A mounds (Rea-
gan 1982). The use of hay-stacking
equipment is a cultural practice change
that, in effect, reduces the pest status
of the IF A by reducing worker exposure
in hay harvesting operations.
2. Other Mechanical Disturbances
The idea that IF A colonies can be
destroyed simply by digging up or
disrupting mounds has been disputed in
extensive research by Blust et al.
(1982). In pastures, dragging or knocking
down the tumulus of the mounds during
the winter resulted in greater than 50%
season-long control, but only when the
dragging was conducted just prior to the
occurrence of freezing temperatures.
Dragging at other times seems to result
only in reducing mound size and thus
reduces interference with haymowing
equipment (Blust et al. 1982).
3. Flooding and Control Burns
Flooding does not destroy or kill IF A
colonies. No information is available,
however, on the effects of flooding for
varying periods of time on the density of
IF A colonies.
Controlled burns have not been shown
to negatively affect IFA populations.
Recent studies by the USDA in sugar-
cane fields near Lake Okeechobee, Flor-
ida, have shown that burns at harvest
time may have more effect on other
species of ants than on IFA. The IFA
apparently escape the fire by moving
deep into their mounds.
Pest Management—Research Needs
Ultimately, a pest management program
needs to be developed for the IFA. Such a
program must be based on sound, biological
and ecological knowledge of the ant as well
as sound, economic and sociological infor-
mation. Economic thresholds, nuisance
thresholds, cost/benefit ratios, beneficial
effects, and environmental and other
external costs must all be accounted for.
At present, very little of the information
and technology needed for a pest manage-
ment program (as opposed to single control
efforts) are available. A pest management
program on the scale needed for the IFA
would require an institutional framework
capable of integrating information and
making decisions. Such a framework also
would aid in allocating funds into necessary
research.
Figure 1 is a prototype management sup-
port system. Data from the ecosystem,
obtained via monitoring, are recorded and
evaluated such that decisions can be made
in designing management systems. As man-
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agement schemes are implemented in eco-
systems, they are monitored, and the sup-
port cycle continues. In such a system,
communications are vital: the public needs
to be informed; staff must know what is
going on and must have input into decisions;
and peer review of research must be main-
tained. Figure 1 shows a two-way link with
the decision/evaluation system and the com-
munication system.
DELIVERY.
SYSTEM
•*• ECOSYSTEM
.MONITORING
SYSTEM
MANAGEMENT
SYSTEM "*~~
DECI
EVALL
SYS
SION/
IATION •*—
TEM
RECORDING
SYSTEM
COMMUNICATION
SYSTEM
Public Staff
1
Peer
Figure 1. A management support system for an ecosystem or
research site.
The implementation of effective pest
management practices depends on the sup-
Port and development of basic research to
Provide the necessary tools. Knowledge of
the ecology and population dynamics of the
and its impact on the environment is
vital to developing effective pest man-
agement programs. In addition, methods of
survey, detection, and control (including
non-chemical, cultural, mechanical, physi-
cal, and biological) must be developed. Re-
search is also needed on specific solutions to
specific problems caused by the IF A; these
solutions may not necessarily involve con-
trol.
1. Economics
The economic impact of IFA as a
human and animal pest is difficult to
assess. Before any pest management
system can be effectively implemented,
a cost-benefit analysis must be made.
The economic losses need to be balanced
against the economic benefits provided
by the IFA. Will control lead to other
pest outbreaks? If the IFA is eliminated
from an area, repopulation usually
occurs within one year. Is this due to a
void left by the IFA's removal, and can
this void be filled with another non-pest
species of ant that would provide the
beneficial effects of the IFA?
The human health problem needs to
be more clearly defined. More accurate
data are needed on the number of people
stung, the number that develop hyper-
sensitivity, and the economic and
psychological effects of these attacks
(Adams and Lofgren 1981, Lofgren and
Adams 1982, Clemmer and Serfling 1975,
Rhoades et al. 1977). The factors in the
venom that cause the anaphylactic reac-
tion must be identified so that measures
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can be developed for people whose lives
are threatened.
2. Ecology and Population Dynamics
Our present knowledge of IF A
ecology and population dynamics is rudi-
mentary, at best, and filled with major
gaps. Little information exists on age-
specific mortality, development rates,
colony growth rates under various condi-
tions, reproduction, limits to growth,
factors controlling growth, and many
other subjects. There is little quantita-
tive information on trophic relations
with respect to growth and reproduction,
and on the limitations food imposes on
growth and reproduction. Interaction of
the colony with the environment is also
poorly described, and the effects of sea-
son, temperature, and rainfall are under-
stood only generally. For this and other
reasons, estimates of the potential range
of the IF A are mere guesses.
There is even less information on the
population dynamics of colonies. No
information exists on the life span of
colonies under various conditions nor on
the age-specific mortality among
colonies throughout the colony cycle.
Such information is essential to under-
stand the vulnerable phases of the life
cycle at which pressure might be applied
most effectively. Also along these lines,
only very general, non-quantitative
information is available on the process
of colonization of a new habitat, be it on
the spreading margin of the IF A range,
or in long-occupied areas. What site
preferences are involved in colonization?
How do physical and biological factors
affect success? What is the nature of
inter-colony relationships as the colonies
increase in size? The role of territorial
behavior? And so on, for a long list of
unanswered questions.
Finally, at the level of the relation-
ships of IF A colonies to other plants and
animals in the community, we have
another knowledge vacuum. Because it
seems so important to IFA success, the
relationship of IFA to other ants greatly
demands study. It is becoming apparent
that other ants may become key consid-
erations in any management attempts.
Information of IFA exploitation of the
community, both plant and animal, and
its impact upon that community is also
largely unavailable.
3. Biology
Social biology of the IFA has
received some attention, but much re-
mains arcane. While the role of the
queen is generally obvious at a crude
level, many questions of queen function
and queen number remain unanswered.
Why are there sometimes multiple
queens, how do they affect colony func-
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tion, queen replacement, colony growth
and reproduction?
A thorough understanding of the ant's
feeding behavior and social interactions
is needed. Research on foraging strate-
gies of workers, recruitment to food,
natural attractants and repellents,
changes in food preference, distribution
of food within the nest, and the influ-
ence of foods or bait type on the distri-
bution of control agents are needed to
develop more effective, species-specific,
safer baits.
Development times, conditions that
trigger the production of reproductive
forms, age of the colonies, the life span
of the various castes, as well as colonies,
and queen replacement, colony recogni-
tion, social communication (apart from
the behavioral chemicals), are but a few
of the biological factors that need to be
investigated for effective management
of this insect.
4. Physiology
The endocrine system regulates many
behaviors and functions of the ant colony
yet there is little knowledge concerning
this important system. Research on en-
docrine glands is needed if we are to
understand IFA reproduction and devel-
opment, queen tolerance, the problem of
single vs. multiple queen colonies, con-
trol of mating, caste determination,
gene expression, and others.
The nutrition, digestion, and absorp-
tion of foods is important to the success
of the colony. Very little is known about
essential nutrients for colony growth and
about IFA enzyme systems and their
specificity. Studies in these areas could
lead to new control methods because
growth, development, reproduction, and
competition are readily influenced by
colony nutrition.
A study of the biochemical transfor-
mations which the IFA is capable of
could be useful because compounds not
metabolized by the ant can be used to
design control methods based on analogs
of metabolizable compounds, such as
hormones or the more degradable toxi-
cants. The biosynthetic pathways for
the pheromones, venom alkaloids, and
other chemicals utilized by the ants need
investigation.
The flight muscles of the queen are
extremely important because they are
used in the mating flight and dispersal of
the queens and provide food for the
larvae during colony founding. Interfer-
ence with colony founding might be pos-
sible if this process were better under-
stood.
Mating and colony foundation may be
vulnerable points in the IFA's life cycle,
but the physiological details are virtually
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unknown. What triggers the mating
flight? Are pheromones involved? How
is wing casting initiated? How far do
the sexuals fly? How does the queen
select sites for colony foundation?
5. Control Tactics and Management
Strategies
Chemical Control: In addition to a
search for slow-acting compounds that
kill, bioassays to detect compounds that
interfere with other biological processes
need to be developed. These could
include spermaticides, reproductive in-
hibitors, or muscle inhibitors. Tech-
niques for field evaluation of control
tactics must be improved so that the
effectiveness of compounds for control
can be evaluated.
Insect growth regulators show
promise, but more research is needed on
their metabolic breakdown, distribution,
and persistence. Also, field tests should
be extended to determine the best way
to utilize the insect growth regulators
for IF A control, keeping in mind that
these materials will not be specific to
IF A. Along this line, behavioral chemi-
cals offer great promise as they may
provide specificity for baits, lead to new
baits, and interfere with the social or-
ganization of the colony.
Behavioral chemicals may lead to
new delivery systems that might be use-
ful for introduction of a pathogen. Path-
ogens will probably require delivery sys-
tems quite different from those for toxi-
cants.
Biological Control: Pathogens, para-
sites, and predators may have potential
for controlling or managing the IF A;
however, no effective biological control
agents have been found. Part of the
difficulty is the lack of research, study
facilities, and financial support in the
IFA's homeland where such biological
control agents would most likely be
found. An IF A research station needs to
be developed in South America.
Genetic Control: Because the IF A
has a haplo-diploid sex-determining sys-
tem, development of a sterile male con-
trol tactic may be possible. Also,
because the IF A mate only once, an
artificial mating technique that has been
developed may prove useful in a manage-
ment program. Genetics is also impor-
tant in other ways such as biological
control and taxonomy.
Physical and Cultural Control:
Research is needed on interrelationships
of IF A to the conditions created by dif-
ferent types of land management (i.e.,
various types of plows and cultivators,
frequency of cultivation and tilling in
annual crops, and the time of year of
cultivation). Trends toward no-tillage
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105
crop production additionally support
these needs. However, more detailed
population dynamics studies on IFA
interaction with other species in these
various habitats under cultural changes
is an essential component to answering
these needs. The potential interactions
of the IFA with weeds and associated
fauna are additional areas for study. In
most annual crops, however, the pest
status of the IFA remains undetermined.
The potential for making valuable
contributions and increasing the impact
of control tactics in this important area
depends heavily on the quality and
extent of population dynamics research.
Only when the ecology of IFA at both
the mound and community levels is bet-
ter understood are we likely to realize
applied advances in physical and cultural
controls. Because these types of control
tactics often have some of the greatest
long-term impact on pest populations,
this research merits some of the highest
priority. Relating this research to eco-
logical studies also will help clarify the
true pest status of the IFA as it inter-
acts with more traditional pests in pro-
duction agriculture.
SPECIAL ORGANIZATIONAL ISSUES &
AGENCY RESPONSIBILITIES
Due to the establishment of the IFA in a
variety of habitats, the responsibilities for
its management reside with different organ-
izations ranging from the home owner to
federal agencies. Because of this situation,
the responsibilities of the organizations con-
cerned with IFA research, education, and
management must be defined, and a mech-
anism to provide effective, safe, and eco-
nomically feasible management programs
must be established. The mechanism should
provide short and long-range planning to
address the needs for research, education,
operations, and regulatory agencies.
Research
USDA/ARS and the SAES's of the
affected states conduct IFA research.
Yearly meetings of an IFA working group
help coordinate the research activities of
the USDA/ARS and SAES's. Congress has
authorized the ARS to conduct mission-
oriented research on the IFA to support
federal and state-controlled programs. This
research includes developing chemical and
biological methods to control the IFA. In
addition, the research provides information
and control techniques for the general pub-
lic.
The SAES's are mandated by their legis-
latures to conduct research and to develop
IFA management strategies to meet the
needs of the public. This research varies
from state to state, and cooperative pro-
grams are encouraged to effectively utilize
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106
human and financial resources and data ex-
change. Basic and applied research on IFA
biology, behavior, population dynamics, sys-
tems ecology, and control strategies are
being conducted. Unfortunately, little or
nothing has been done to determine pest
status and economic thresholds for this
insect.
Education
The IFA has become a volatile emotional
and political issue debated in public and
private, frequently on the basis of gross
ignorance or misconceptions about the
insect and the problems it poses. The insect
has not escaped the attention of any seg-
ment of the population within its present
range, and is an issue even well outside of
its range. There is an important need for an
educational program, organized and promul-
gated by a responsible and authoritative
agency, to ensure that those who need or
desire accurate information about the IFA
can obtain it easily. The program should be
structured so as to reach specific audience
groups with information appropriate to their
respective needs. Among the more impor-
tant of these groups are lay citizens in
urban and agricultural areas; members of
the news media; special interest and civic
groups, such as those concerned with envi-
ronmental quality or gardening; state and
federal legislators; appropriate administra-
tors at all levels of federal, state, and local
government; and members of pest or agri-
culture-related businesses. Each group
needs information relevant to the fulfill-
ment of their role in society be it as public
officials involved in making decisions rele-
vant to IFA or as private citizens exposed to
IFA.
Reliable, objective, and unsensational-
ized information on the nature of the prob-
lem posed by IFA is of greatest immediate
need because this is the issue around which
most public and private debate revolves.
The medical problem should be defined on
the IFA as a nuisance to the average human
and as a hazard to sensitive individuals. The
problem in terms of the numbers of sting
victims and deaths due to stings, the rela-
tive hazard in various situations (e.g., urban,
rural) and the availability of preventive
medical treatment for the overly sensitive
should be fully explained. Livestock,
poultry, and agricultural production prob-
lems also should be explored in depth. In all
cases, it will be important to differentiate
between perceived problems, based on opin-
ion or unsubstantiated anecdotal evidence,
and demonstrable effects resulting in medi-
cal, economic, or ecological harm or bene-
fit.
The public needs information to be able
to accurately assess any IFA problem they
may face to determine whether or not
remedial action is necessary, and if neces-
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107
sary what action would be most beneficial
(chemical or nonchemical). To broaden
their understanding of the IF A, the public
also should be educated on the biological
role of the IFA in the environment.
These educational needs are admirably
suited to the missions and capabilities of the
Extension Service of the USDA and the
cooperative extension services of the
affected states. Information should be col-
lected and collated at the federal level by
the Extension Service and should be dissemi-
nated through the cooperative extension
services for adaptation and use in their
respective extension programs. In addition,
it will be equally or more important for
Extension to be actively involved in the
educational phases and information dissemi-
nation of new technology as it is developed
by research.
Role of APHIS in IFA Program
The Animal and Plant Health Inspection
Service (APHIS), as mandated by Congress
under three plant pest acts, is responsible
within the USDA for survey, regulatory, and
control activities of the IFA. Due to the
anticipated cancellation of mirex and chlor-
dane, an ARS/APHIS Working Group was
formed in 1977 to study future control tech-
nology, including chemicals, that could be
used by APHIS and its cooperators in future
IFA programs. The Working Group consists
of three scientists from each of the two
services who carefully review research
needs and the research and methods devel-
opment efforts that jointly affect the ARS
and APHIS.
Soon after creation of the Working
Group, it became apparent that there was a
need to involve other services from within
the USDA, the states, the EPA, and the
chemical industry to expedite urgently
needed "tools" to regulate and control the
pest. Consequently, the Working Group has
guided progress to date with invited input
from the states, EPA, and chemical
industry. This procedure could be developed
into a permanent policy and decision-making
mechanism to plan all future programs
involving the IFA.
It is anticipated that the APHIS will
continue to carry out its mandated charter
of IFA survey and regulatory responsibilities
in conjunction with its cooperators.
Involvement of APHIS in future IFA control
programs will depend on its congressional
mandate. It should be noted that Panel I of
this Symposium concluded that a rationale
does not exist for large-scale IFA eradica-
tion or control programs. Such federally-
supported programs have not been success-
ful in eradicating the pest nor in keeping it
from being widespread in the southeastern
United States. This suggests that the role
of APHIS in IFA programs should be the
same as for any other established pest
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species.
Regulatory
As mandated by Congress under the
Federal Insecticide, Fungicide and Rodenti-
cide Act (FIFRA), the EPA is responsible for
pesticide registration. To adequately evalu-
ate the environmental impact of potential
IFA controls (chemical or biological), the
EPA needs specific data demonstrating the
safety and utility of the controls. These
data generally include product chemistry,
toxicology, environmental chemistry, eco-
logical effects, and efficacy information.
The extent and volume of specific tests
needed for IFA control primarily depend on
(1) target sites, i.e., agricultural vs. non-
agricultural, rural vs. urban; (2) use patterns
including rates and methods of application,
i.e., aerial, ground broadcast, mound treat-
ment, quarantine; (3) user groups, i.e., agri-
cultural, commercial, PCO, homeowners; (4)
size of treatment area; and (5) pesticide
classification of the compound (biological,
biorational, conventional pesticide).
Early access to the above information
would enable EPA to (1) evaluate the exist-
ing data base on old and new IFA control
agents and (2) identify data gaps, research
needs and/or environmental problems early
in the planning activity. This would then
enable EPA to provide an appropriate and
timely decision on an IFA pesticide—approv-
ing or denying registration, requiring further
studies, or waiving additional data. In add-
ition, EPA's regulatory responsibilities can
better serve future IFA control programs if
it can participate in the preliminary deliber-
ations concerning future management
strategies.
RECOMMENDATIONS
1. Determining the pest status and develop-
ing economic thresholds for the IFA in
various ecosystems should receive the
highest priority for additional research.
Furthermore, pest management
strategies should be developed for the
IFA. However, because most of the
tactics needed for such an IPM program
have not yet been developed, additional
funding should go to basic and applied
research. The information from this
research would enhance the development
of practical and effective pest manage-
ment strategies for the IFA by providing
a better understanding of the biology and
ecology of the ant in each of its
habitats.
2. The research should include investiga-
tions for effective and economical alter-
native chemicals as well as non-chemical
methods. The latter efforts should
emphasize biological and non-chemical
alternative control measures suitable for
homeowner use.
3. To provide responsible agencies with a
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clearer definition of the existence and
scope of the problem, an unbiased third
party should conduct a thorough scienti-
fic survey on the economic and human
health importance of the IF A. To assist
this third party, a small resource panel
could be formed, consisting of an eco-
nomist, one or two representatives from
SAES, and a representative from each of
EPA, APHIS, ARS, a state department of
agriculture, and a public health agency.
4. An educational program should be organ-
ized and promulgated by a responsible
and authoritative agency to ensure easy
access to accurate and useful informa-
tion on the IF A. The program should
reach specific audience groups with in-
formation appropriate to their respec-
tive needs. The agencies to fulfill these
educational needs are the Extension Ser-
vice of USDA and the cooperative exten-
sion services of the affected states.
5. Chlordane should be re-registered for
quarantine treatment use only, until a
suitable and satisfactory alternative is
found.
8. A comprehensive research planning and
action program should be developed and
implemented through existing or new
mechanisms of the Southern Regional
Association of State Agricultural Experi-
ment Stations. Existing mechanisms
provide for strong interaction between
all interested state and federal agencies.
7. An Inter Agency Task Force should be
established to mobilize available
resources to develop a comprehensive 5-
year program to include research, educa-
tion, and action activities to develop
management strategies for the IF A. Key
agencies should include APHIS, ARS,
CSRS, Extension and ERS of USDA; the
EPA; the state agricultural experiment
stations, cooperative extension services,
and state departments of agriculture in
affected states; and various state uni-
versities. Other agencies with an inter-
est in the IF A include DOD and NIH.
The NSF should be encouraged to support
research on other ant species to provide
basic knowledge that could contribute to
the development of IF A management
programs.
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Adams, C. T. and C. S. Lofgren. 1981. Red
imported fire ants (Hymenoptera: For-
micidae): frequency of sting attacks on
residents of Sumter County, Georgia. J.
Med. Entomol. 18:378-382.
Adams, C. T. and C. S. Lofgren. 1982.
Impact of the red imported fire ant,
SoZenopsis invicta on the growth and
yield of soybeans. Florida Entomol.
(Submitted for pub.).
Apperdon, C. S. and E. E. Powell. 1982.
Correlation of the red imported fire ant,
Solenopsis invicta Buren, with reduced
soybean yields in North Carolina. J.
Econ. Entomol. (Accepted for pub.).
-------
110
Banks, W. A. 1982. The effects of insect
growth regulators and their potential as
control agents for imported fire ants.
Florida Entomol. (Accepted for pub.).
Blust, W. E., B. H. Wilson, K. L. Koonce, B.
D. Nelson and J. E. Sedberry, Jr. 1982.
The red imported fire ant, Solenopsis
invicta Buren: cultural control and
effect on hay meadows. L.S.U. Ag. Exp.
Stn. Bull. No. 738. 27 pp.
Burns, E. C. and D. G. Melancon. 1977.
Effect of imported fire ant (Hymenop-
tera: Formicidae) invasion on lone star
tick (Acarina: Ixodidae) populations.
Iowa Med. Entomol. 14:247-9.
Clemmer, D. L. and R. E. Serfling. 1975.
The imported fire ant: dimensions of the
urban problem. South Med. J. 68:1133-
38.
Howard, F. W. and A. D. Oliver. 1978.
Arthropod populations in permanent pas-
tures treated and untreated with mirex
for red imported fire ant control.
Environ. Entomol. 7:901-3.
Howard, F. W. and A. D. Oliver. 1979.
Field observations of ants (Hymenoptera:
Formicidae) associated with red
imported fire ants, Solenopsis invicta
Buren, in Louisiana pastures. J. Georgia
Entomol. Soc. 14:259-62.
Jouvenaz, D. P., C. S. Lofgren and W. A.
Banks. 1981. Biological control of the
imported fire ants: a review of current
knowledge. Bull. Entomol. Soc. 27:20-3-
8
Lofgren, C. S. and C. T. Adams. 1981.
Reduced yields of soybeans in fields
infested with the red imported fire ant,
Solenopsis invicta Buren. Florida
Entomol. 64:199-204.
ant in the United States. Proc. 9th Int.
Congress of the Int. Union for the Study
of Social Insects. Boulder, CO. August
9-13, 1982
Oliver, A. D., T. E. Reagan and E. C. Burns.
1979. The fire ant—an important preda-
tor of some agricultural pests. Louisiana
Agric. 22(4):6-7,9.
Reagan, T. E., G. Coburn and S. D. Hensley.
1972. Effects of mirex on the anthropod
fauna of a Louisiana sugarcane field.
Environ. Entomol. 1:588-91.
Reagan, T. E. 1982. Sugarcane borer pest
management in Louisiana: leading to a
more permanent system. Proc. Second
Inter-American sugarcane seminar-
Insect and Rodent Pests 1981, Florida
International Univ. (Oct. 6-8) (In press).
Rhoades, R. B., W. L. Shaeffer, M. Newman,
R. Lockey, R. M. Dozier, P. F.
Wubbena, A. W. Townes, W. H. Schmid,
G. Neder, T. Brill, and H. V. Wittig.
1977. Hypersensitivity to the imported
fire ant in Florida: A report of 104
cases. J. Fla. Med. Assoc. 64:247-54.
Stam, P. A. 1978. Relation of predators to
population dynamics of Nezara viridula
(L.) in a soybean ecosystem. Ph.D. Dis-
sertation L.S.U. Baton Rouge, LA.
White, E. A. 1980. The effects of stubbling
and weed control in sugarcane on the
predation of the sugarcane borer,
Diatraea saccharalis (P.). M.S. Thesis.
L.S.U. Baton Rouge, LA. 216 pp.
Lofgren, C. S. and C. T. Adams. 1982.
Economic aspects of the imported fire
-------
List of Registrants
-------
REGISTRATION LIST
IMPORTED FIRE ANT SYMPOSIUM
JUNE 7-10, 1982 - ATLANTA, GA.
ADAMS, C. T.
USD A Ag. Res. Ctr.
P. O. Box 14565
Gainesville, FL 32604
ALLEN, George
CR/USDA
Room 6440, South Bldg.
14th & Independence Ave. S.W.
Washington, D. C. 20250
ALLEN, John C.
Ag. Res. & Ed. Ctr.
P. O. Box 1088
Lake Alfred, FL 33850
ALLEY, Earl L.
Miss. St. Chem. Lab.
P. O. Box CR
Mississippi State, MS 39762
ALLISON, John R.
Dept. of Agric. Economics
Georgia Exp. Station
Experiment, GA 30212
APPERSON, Charles S.
North Carolina State Univ.
P.O. Box 5215
Raleigh, NC 27650
ASHTON, W. Eric
Velsicol Chem.
341 E. Ohio St.
Chicago, IL 60611
ASPELIN, Arnold
BFFD-EPA, Rm. 700, CM #2
410 Elm St., S.W.
Washington, DC 20460
BAGENT, J. L.
Entomology Dept.
Louisiana State Univ.
Baton Rouge, LA 70893
BANKS, W. A.
USDA-SEA-AR
P. O. Box 3269
Gulfport, MS 39503
BARRON, R.
American Cyanamid Co.
Agricultural Div.
P. Q. Box 400
Princeton, NJ 08540
BARTLETT, Thomas L.
The Andersons
P. 0. Box 119
Maumee, OH 43537
BATTENFIELD, Susan
Dept. of Entomology
Michigan State Univ.
East Lansing, MI 48824
BLUM, Murray
Dept. of Entomology
Univ. of Georgia
Athens, GA 30602
BOWEN, John M.
College of Veterinary Medicine
Univ. of Georgia
Athens, GA 30602
BRIDGES, J. Thomas
Maag Agrochemicals R&D
P. O. Box X
Vero Beach, FL 32960
BROADBENT, David J.
S. C. Johnson Wax
17 Globe Heights Dr.
Racine, WI 53406
BROOKS, Ted
Ag. Ext. Serv.
P. O. Box 5426
Mississippi State, MS 29762
BROWN, Ralph
Florida Dept. of Ag.
P. O. Box 1269
Gainesville, FL 32611
BROWN, Reagan
Texas Dept. of Agric.
P. O. Box 12847
Austin, TX 78711
BUREN, W. L.
Ent. & Nem. - McCarty Hall
Univ. of Florida
Gainesville, FL 32611
BUSHMAN, Greg
Stauffer Chem. Co.
636 California St.
San Francisco, CA 94108
BUTTERFIELD, D.
American Cyanamid Co.
Agric. Div.
Wayne, NJ 07470
CAMPBELL, Robert
USFS - Pac. NWF & RES.
3200 Jefferson Way
Corvallis, OR. 97331
CAMPBELL, J. Phil
Watkinsville, GA 30677
CAMPT, Douglas
EPA - Reg. Div. TS-767C
401 M St., S. W.
Washington, DC 20460
CANERDAY, Don
Entomology Dept.
Univ. of Georgia
Athens, QA 30602
CARLSON, Gerry A.
Dept. of Ag. Econ.
North Carolina State Univ.
Raleigh, NC 27607
CARR, Carolyn
Gulf Coast Reg/Sierra Club
342 Payne St.
Auburn, AL 36830
CARROLL, C. Ronald
Inst. of Environ. Studies
Baylor University
Waco, TX 76701
CASE, Roger S.
Mississippi State Chem. Lab.
407 D Carver Drive
Mississippi State, MS 39759
CLARK, J. Derrell
College of Vet Med
Univ. of Georgia
Athens, GA 30602
CLARK, Roy
EPA - Region 14
345 Courtland St., N.E.
Atlanta, GA 30365
COLEY, Jack D.
Miss. Dept. Ag.
Box 5207
Mississippi State, MS 39762
COLLINS, Homer L.
USDA-APHIS
P. O. Box 2278
Gulfport, MS 39503
CONLEY, J. R.
Dept. of Agric. Rm. 601
Agric. Bldg., Capitol Square
Atlanta, GA 30334
COOPER, Raymond B.
Blanco Prod. Co./Lily Res. Lab.
P. O. Box AB
Albany, GA 31706
CREEK, Ken
The Environmental Group
Lake St. Louis, MO 63367
CRUZ, Carlos
Agric. Exp. Sta. U.P.R.
Box 506 Isabela
Puerto Rico, P. R. 00662
111
-------
112
DAVIS, James A.
DMA Associates
308 E. Capitol Street
Washington, D.C. 20003
DAY, Edgar W.
Eli Lilly & Co.
Greenfield Lab.
Greenfield, IN 46140
DENNE, Thomas W.
EPA
345 Courtland St., N.W.
Atlanta, GA 30338
DOVER, Michael J.
EPA IPM Unit TS768C
Office of Pesticide Prog.
Washington, DC 20460
DUNKLE, Ric
USDA - ARS Pest. Mgt.
Rm. 420A, Admin. Bldg.
12th & Independence, S.W.
Washington, DC 20250
EIMANIS, Andy
Velsicol Chem. Corp.
341 E. Ohio St.
Chicago, IL 60611
Elliott, H. John
Power Research Corp.
P. O. Box 356
Fairfax, VA 22030
ELLIOTT, Wayne T.
Southeastern Legal Foundation
Suite 950, 1800 Century Blvd.
Atlanta, GA 30345
FAIRCHILD, Homer
USDA - APHIS, Room 600
6506 Bellcrest Rd., Fed. Bldg. f 1
Hyattsville, MD 20782
FANCHER, Charles C.
MS Dept. of Agric. & Com.
6219 Waylawn Drive
Jackson, MS 39206
FERRIS, John
Entomology Dept.
Purdue University
West Lafayette, IN 47907
FIFIELD, Richard G.
Alabama Farm Bureau Fed.
Montgomery, AL 36198
FLETCHER, David J. C.
University of Georgia
Dept. of Entomology
Athens, GA 30602
FLUKER, Sam S.
FL Cooperative Ext. Service
Bldg. 803, Rm. 4, Univ. of Fl.
Gainesville, FL 32611
FRANKIE, Gordon
Dept. of Entomology
Univ. of Calif.
Berkeley, CA 94720
FRANKS, Oscar
Texas Tech.
Dept. of Entomology
Lubbock, TX 79408
FRANKLIN, John A.
USDA - APHIS
6506 Bellcrest Rd. Fed Bldg. #1
Hyattsville, MD 20782
GEISER, Stan
Blanco Products Co.
740 S. Alabama St.
Indianapolis, IN 46285
GILCHRIST, Jack
Dept. of Agriculture
Rm. 230 Agri. Bldg. Capitol Sq.
Atlanta, GA 30334
GILSTRAP, Frank E.
Dept. of Entomology
Texas A&M University
College Station, TX 77843
GLANCY, Mike
USDA - ARS
P. O. Box 14565
Gainesville, FL 32604
GLATZ, George
Montedison USA, Inc.
1114 Ave. of the Americas
New York, NY 10036
GOLDSCHMIDT, Steven
Pesticide & Toxic Chem. News
1101 Pennsylvania Ave., S.E.
Washington, DC 20003
GRAHAM, David B.
Velsicol Chem. Corp.
341 E. Ohio St.
Chicago, IL 60611
GRAVES, Jerry B.
Dept. of Entomology
Louisiana State Univ.
Baton Rouge, LA 70803
GROSSO, Louis S.
Merck & Co.
Three Bridges, NJ 08887
GUILBEAU, S. Wayne
LA Dept. of Agriculture
Rm. 231, Harry D. Wilson Bldg.
Baton Rouge, LA 70802
HARDEN, Adron
Legislative Director
GA Farm Bureau
Macon, GA 31290
HAYES, Frank A.
Prof, of Veterinary Medicine
University of Georgia
Athens, GA 30603
HAYNES, Dean L.
Dept. of Entomology
Michigan State Univ.
E. Lansing, MI 48824
HAYS, Kirby L.
Dept. of Zoology-Entomology
Auburn University
Auburn, AL 36830
HAYS, Sid B.
Dept. of Entomology
Clemson Univ.
Clemson, SC 29631
HEADLEY, J. Charles
Dept. of Agric. Economics
Univ. of Missouri
Columbia, MO 65211
HEIER, Albert J.
EPA
401 M St., S.W.
Washington, DC 20460
HELLER, Billy L.
Florida Farm Bureau
P. O. Box 730
Gainesville, FL 32602
HESS, Susan
USDA Plant Prot & Quar. Branch
14th & Ind. S.W. So. Bldg. Rm. 1148
Washington, DC 20250
HIGBEE, F. Farreli
Inn. Agric. & Aviation Con.
1030 Fifteenth St. N.W. Suite 840
Washington, DC 20005
HILL, K.
American Cyanamid Co.
P. 0. Box 400
Princeton, NJ 08540
HILLEBRECHT, Wayne R.
Stauffer Chem. Co.
1828 L St., N.W.
Washington, DC 20036
HINKLE, Maureen
National Audubon Soc.
645 Pennsylvania Ave. SE
Washington, DC 20003
HOOD, Kenneth J.
EPA
Office of Research
Washington, DC 20460
HORNE, Thomas J.
Centers for Disease Control
1600 Clifton Rd.
Atlanta, GA 30306
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113
HORTON, P. Mac
Dept. Ent., Fisheries <5c Wildlife
103 Long Hall
Clemson University
Clemson, SC 29631
HSIAO, Ting H.
Biology Science Dept.
Utah State Univ.
Logan, UT 84322
ILLNICK, Frank
Montedison USA, Inc.
1114 Ave. of the Americas
New York, NY 10036
INGRAM, Reba L.
Miss. St. Chem. Lab.
P. O. Drawer CR
Mississippi State, MS 39762
JACKSON, H. B.
Plant Pest Reg. Serv.
Clemson University
Clemson, SC 29631
JAMES, Frank, M.D.
1635 N. E. Loop
San Antonio, Tx 78209
JENKINS, Quentin
Dept. Rural Sociology
Louisiana State University
Baton Rouge, LA 20893
JETER, Charles
Regional Administrator
EPA
Atlanta, GA 30365
JOHNSON, Donald R.
Univ. of Arkansas
P. 0. Box 391
Little Rock, AR 72203
JOHNSON, Donald R.
Entomologist Consultant
1362 N. Decatur Rd. N.E.
Atlanta, GA 30306
JOHNSON, M.
American Cyanamid Co.
P. O. Box 400
Princeton, NJ 08540
KARR, Guy W.
Ala. Dept. of Agric. & Ind.
P. O. Box 3336
Montgomery, AL 36193
KASS, Robert E.
IMC
666 Garland PL
Des Plaines, IL 60016
KEARNEY
USDA - APHIS
RR #6, Box 53
Wilmington, NC 28405
KOGAN, Marcus
Univ. of 111. Nat. Hist. Survey
174 Nat. Res. Bldg.
Urbana, IL 61801
LAPLANTE, Richard H.
Humko Chemical
920 Green St.
Conyers, GA 30207
LAROCCA, George
TS 793, EPA
Office of Toxic Substances
Washington, DC 20460
LEE, Jim
USDA - APHIS 313 E. Admin. Bldg.
14th & Independence Ave., S.W.
Washington, DC 20250
LIGNOWSKI, Edward M.
American Cyanamid Co.
P. 0. Box 400
Princeton, NJ 08540
LINKFIELD, R.
American Cyanamid Co.
P. 0. Box 400
Princeton, NJ 08540
LIPSEY, Richard L.
KENCO Chem. Corp.
Jax, FL 32263
LOFGREN, Clifford
Sci. & Ed. Admin.
Univ. of Florida
Gainesville, FL 32611
LOGAN, Jesse
Dept. Zool. & Entomology
Colorado State Univ.
Fort Collins, CO 80523
LOMBARDI, Richard W.
American Cyanamid Co.
Agric. Div.
Wayne, NJ 07470
LUKASIK, Frank J.
Stauffer Chemical Co.
Agri. Chem. Div.
Westport, CT 06880
MALTBY, Raymond H.
Stauffer Chemical Co.
920 Rockefeller Dr. Apt. 16A
Moutain View, CA 94042
MARTIN, Karen K.
221 Laramie Rd.
Griffin, GA 30223
MAXWELL, Fowden G.
Entomology Dept.
Texas A&M University
College Station, TX 77843
McCOOK, Shelby A.
Dept. of Commerce
One Capitol Mall 6th FL
Little Rock, Ark. 72201
McGILL, Sam P.
Sena tor 24T11
State of Georgia
Washington, GA 30673
McNEAL, C. David
USDA Ext. Serv. - IPM Prog.
5547 - S.
Washington, DC 20250
McNEILL, Kenny E.
Elanco Products Co.
740 S. Alabama St.
Indianapolis, IN 46285
MERRICK-GASS, M.T.
United Brands Co.
1271 Avenue of the Americas
New York, NY 10020
METCALF, Robert L.
Dept. of Entomology
Univ. of Illinois
Urbana, IL 61801
MILIO, John
USDA - ARS
P. O. Box 14565
Gainesville, FL 32604
MILLER, Don H.
Ketron, Inc.
1700 N. Moore St., Rosslyn Ctr.
Arlington, VA 22209
MILLS, Gayle M.
Zoecon Corp.
975 Calif. Ave.
Palo Alto, CA 94304
MURPHY, N. B.
Ark. State Representative
S. Main St.
Hamburg, Ark. 71646
MUSICK, Jerry J.
University of Arkansas
Dept. of Ent. - Ag. 319
FayetteviUe, Ark. 72701
NEELY, James M.
USA Environmental Hygiene
U. S. Army, RD - South Bldg. 180
Ft. McPherson, GA 30330
NEWTON, Steve M.
Georgia Farm Bureau
P. O. Box 7068
Macon, GA 31298
NIGG, Herbert
IF AS Ag. Res. & Ed. Ctr.
P. O. Box 1088
Lake Alfred, FL 33850
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114
NORMENT, Bev R.
Miss. State University
P. O. Drawer EM
Mississippi State, MS 39762
OFIARA, Douglas D.
Dept. of Ag. Economics
Georgia Exp. Station
Experiment, GA 30212
O'NEIL, J.
American Cyanamid Co.
2997 Gant Place
Marietta, GA 30060
ORLOSKI, E.
American Cyanamid Co.
P. 0. Box 400
Princeton, NJ 08540
OSTROZYNSKI, R. L.
Hooker Chemicals & Plastics
P. O. Box 159
Niagara Falls, NY 14302
PARCHETA, Tony
Penick Corporation
1603 Princeton West Tr,
Marietta, GA 30062
RANDLE, Kim J.
Arkansas Legislative Council
315 State Capitol
Little Rock, AR 72201
RAWLINS, Don E.
American Farm Bureau Fed.
225 Touhy Aye.
Park Ridge, IL 60068
REAGAN, Thomas E.
Dept. of Entomology, LSU .
402 Life Sciences Bldg.
Baton Rouge, LA 70810
REAVES, Henry L.
GA General Assembly
Route 2
Quitman, GA 31643
REESE, Charles
EPA - RD 682 -
Office of Env. Processors & Ef.
Washington, DC 20460
REID, E. Wayne
Blanco Products Co.
740 S. Alabama St.
Indianapolis, IN 46285
RESELLA, Dita
Stauffer Chem. Co.
1200 S. 47th
Richmond, CA 94804
REYNOLDS, Harold T.
Dept. of Entomology
Univ. of California
Riverside, CA 92521
RISCH, Steven
Dept. Ecol.
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115
TROSTLE, Mark
Imported Fire Ant Specialist
Texas Dept. of Ag.
Austin, Tx 78710
TSCHIRLEY, Fred
Dept. of Botany & Plant Path.
270 Plant Path. Bldg.
Michigan State Univ.
E. Lansing, MI 48824
TSCHINKEL, Walter R.
Oept. of Bio. Sciences
Florida State Univ.
Tallahassee, FL 32306
TUCKER, Melvin C.
Ark. State Plant Board
P. O. Box 1069
Little Rock, Ark. 72203
TURNER, Steve
UELTSCHEY, Marion
Miss. Dept. Agri. & Commerce
P. 0. Box 1609
Jackson, Miss. 39205
VANDER HOOVEN, David I. B.
The Andersons
P. O. Box 119
Maumee, OH 43537
VANDER MEER, Robert K.
USDA - ARS
P. 0. Box 14565
Gainesville, FL 32604
VER STEEGH, L. E.
Tucker Wayne & Co.
230 Peachtree St. Suite 2700
Atlanta, GA 30303
VINSON, S. B.
Dept. of Entomology
Texas A&M Univ.
College Station, TX 77843
WAGNER, J. Noel
Stauffer Chem. Co.
P. O. Box 17207
Raleigh, NC 27619
WANG, T.
American Cyanamid Co.
P. 0. Box 400
Princeton, NJ 08540
WEEKS, D. C.
Plant Pest Reg. Serv.
Clemson University
Clemson, SC 29631
WEIDHASS, Donald E.
USDA-CR
P. O. Box 14565
Gainesville, FL 32604
WELLS, William A.
EPA - Pest. & Tox. Substances
401 MSt.
Washington, DC 20460
WHITE, George O.
Texas Farm Bureau
Rt. 1
Harwood, TX 78632
WHITE, T. J.
American Cyanamid Co.
Agric. Div.
Wayne, NJ 07470
WILLIAMS, David F.
USDA - ARS
P. O. Box 14565
Gainesville, FL 32604
WILLIAMS, Kent C.
EPA Region IV
345 Courtland St.
Atlanta, GA 30365
WILLIAMSON, Bob
USDA Rm. 608 Fed. Ctr. Bldg.
6506 Bellcrest Rd.
Hyattsville,.MD 20782
WOJCIK, Daniel P.
USDA - ARS
P. 0. Box 14565
Gainesville, FL 32604
WOOD, John
USDA Rm. 608 Fed. Ctr. Bldg.
6506 Bellcrest Rd.
Hyattsville, MD 20782
WORK, L. Kenneth
Tucker Wayne & Co.
230 Peachtree St. Suite 2700
Atlanta, GA 30303
WRIGHT, Darwin
Integrated Pest Mgt. R&D
EPA
Washington, DC 20460
YARBROUGH, James D.
Mississippi State Univ.
P. O. Drawer GY
Mississippi State, MS 39762
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Appendices
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APPENDIX A
CHEMISTRY AND PROPERTIES OF
FIRE ANT VENOMS
Murray S. Blum
PANEL IV
The venom of the fire ant, Solenopsis
invicta, in common with those other species
in this genus, is distinguished by the pre-
sence of dialkylpiperidine alkaloids that
have not been detected as natural products
of species in any other taxa. These idiosyn-
cratic alkaloids constitute about 95% of the
poison gland secretion, being accompanied
by a denser aqueous phase that contains
traces of proteinaceous constituents. These
protein-poor, alkaloid-rich venoms contrast
with those of most stinging ants which are
characterized by high concentrations of bio-
logically active proteins and the absence of
detectable alkaloidal constituents.
The venom of workers of Solenopsis in-
victa is dominated by six 2-methyl-6-alkyl-
piperidines that are present primarily as
trans isomers; the cis isomers are relatively
minor constituents. The major alkaloid pro-
duced is trans-2-methyl-6-(cis-6-pentade-
cenyl) piperidine, Trans-2-methyl-6-(cis-4-
tridecenyl)-piperidine also constitutes a
quantitatively important constituent,
whereas 2-methyl-6-(cis-8-heptadecenyl) pi-
peridine is a minor venomous product. The
major saturated alkaloids are trans-2-
methyl-6-n-tridecylpiperdine and trans-2-m
ethyl-6-n-pentadecylpiperidine. Trans-2-
methyl-6-n-undecylpiperidine is a quantita-
tively unimportant product.
The venoms of the four other fire ant
species in North America are qualitatively
less complex than the venom of Solenopsis
invicta. The venom of workers of S. rich-
teri, another introduced species lacks the
dialkylpiperidines with 6-alkyl side chains
greater than C,3. The venoms of workers
of the three native species, S. ryloni, S.
geminata, and S. aurea, are qualitatively
depauperate compared to S. invicta and S.
richteri. In general the venoms of these
native fire ants contain only the cis and
trans isomer of 2-methyl-6-n-undeeylpiperi-
dine, with the former isomer predominating.
The venom of S. xyloni is unique in contain-
1 2
ing 2-methyl-6-undecyl-W ' -piperidine as a
minor constituent, a compound that may
constitute an intermediate in the biosyn-
theses of the cis and trans isomers of 2-
methyl-6-n-undecylpiperidine.
In contrast to the qualitative diversity
that characterizes the venoms of workers of
S. invicta and S. richteri, those of their
queens are depauperate. The venoms of the
queens are dominated by the cis and trans
isomers of 2-methyl-6-n-undecylpiperidine,
the former isomer always predominating.
116
-------
117
None of the dialkylpiperidines with 6-alkyl
side chains greater than C^, which domi-
nate the venoms of the workers of S. invicta
and S. richteri, are present in the venoms of
the queens. The venom of the queen of S.
richteri is also distinguished by the presence
of trace amounts of 2-methyl-6-n-nonylpi-
peridine. In contrast, the venoms of queens
of S. xyloni and S. geminata are similar to
the venoms of their workers in primarily
containing the cis and trans isomers of 2-
methyl-6-n-undecylpiperidine.
Considering the cis isomers as being
therm ©dynamically favored from an ener-
getic standpoint, a hypothetical phenocline
in biochemical evolution for the genus So-
lenopsis was constructed. The venoms of
the queens of S. xyloni and S. geminata
reflect the more primitive state, being qua-
litatively simple and dominated by the cis
isomer of 2-methyl-6-n-undecylpiperidine.
The venoms of the workers essentially mir-
ror those of their queens. Evolution of a
form in which the trans isomers predomi-
nates (a South American species) in the
worker venom would be followed by elabora-
tion of new trans alkaloids in worker venoms
with a 6-alkyl side chain greater than Cjj
(S. richteri) eventuating in a form with side
chains containing C15 and GI? moieties (S.
invicta). Since the venoms of workers of S.
invicta and S. richteri are considerably more
necrotoxic than the simple venoms of S.
ryloni and S. geminata, it is suggested that
the evolution of new trans alkaloids was
highly adaptive for the former pair of spe-
cies.
Three to four proteins are present in the
minor aqueous phase in the venom of S.
invicta. One of these macromoleeular con-
stituents is hyaluronidase; the other is phos-
pholipase. Since the latter enzyme is con-
sidered to be the primary allergen in hymen-
opteran venoms, these minor proteinaceous
constituents probably are responsible for the
allergic reactions experienced by some hu-
man beings after being stung by workers of
S. invicta.
The dialkylpiperidines present in Solen-
opsis venoms possess a wide range of biolo-
gical activities that had been previously
identified with these poison gland secre-
tions. The venom of S. invicta exhibits
well-developed fungicidal, bactericidal, in-
secticidal, herbicidal, and hemolytic activi-
ties; all of these properties can be dupli-
cated with the neat alkaloids. The fungi-
cidal activities of some of the dialkylpiperi-
dines are equal to or are greater than those
of commercially available fungicides. The
pronounced necrotoxicity of the venom, that
results in sterile pustules at the sting sites
on human beings, is directly attributable to
the alkaloids.
A variety of other biochemical lesions
are produced by the dialkylpiperidines.
These alkaloids degranulate most cells,
which frees a histamine and produces algo-
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118
genie and allergic reactions in humans. Ad-
ditionally, these compounds inhibit ATPase
and oxidative phosphorylation, and deleteri-
ously affect sites at the vertebrate neuro-
muscular junction. These pharmacological
activities illustrate the wide range of bio-
chemical lesions that these unique alkaloids
are reported to produce in in vitro investi-
gations.
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APPENDIX B
THE MEDICAL ASPECTS OF THE IMPORTED FIRE ANT
William H. Schmid, M.D.
PANEL IV
Hypersensitivity reactions to stings of
winged Hymenoptera have been described
since antiquity. The imported fire ants,
Solenopsis richteri and Solenopsis invicta,
which have been present in the southeastern
United States for 40 to 50 years, cause
significant medical morbidity by their
stings. In an infested area, IF A stings occur
more frequently than do bee, wasp, hornet
and yellow jacket stings. The human reac-
tion to the stings of these two IF A species is
similar.
The IF A sting produces an uncomfortable
burning sensation and usually results in the
formation of a sterile pustule, 3-5 mm in
diameter at the point of the sting. The
pustule usually disappears after a few days.
Multiple stings from IF A occur because indi-
vidual ants can administer several stings.
The average victim has several stings and 10
to 20 stings are common. The primary site
is characterized by redness followed by a
wheal and a characteristic pustule within six
to twenty-four hours. The pustule is diag-
nostic of an IFA sting.
The overwhelming majority of IFA stings
are uncomplicated. A pigmented area often
develops at the sting site which persists as a
blemish for weeks to months. Secondary
infections can occur when the pustule is
broken. Impetigo is the most common
secondary infection. Severe infections have
occurred requiring skin grafting, amputation
of an extremity or digit, or incision and
drainage of a wound.
Some people experience a generalized
allergic reaction to an IFA sting. These
reactions occur within minutes of a sting
and vary in severity. The reactions can
include generalized hives, facial, genital or
extremity swelling, nausea, vomiting and
shock. Death also can occur. Feet and
ankles usually are stung. The ant anchors to
the skin with its mandibles and then stings
once or several times with its abdominal
stingers.
The following histories demonstrate the
variety of sting situations.
Case I
A 32-year-old Canadian male was stung
by 10 ants while changing a tire on the edge
of the interstate highway in St. Petersburg,
Florida. He became weak and fainted and
was taken to a hospital emergency room
119
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120
where he was found to be in shock and was
hospitalized. He recalled hymenoptera
stings in Canada without difficulty. This
was his first visit to a fire ant infested area
and his first known fire ant sting.
Comment: Over 20% of patients with
anaphylaxis following an IFA sting have a
severe reaction on the first sting.
CaseH
A 25-year-old, male, golf-course worker
experienced repeated severe reactions to
IFA stings that required emergency room
treatment. He was placed on a fire ant
desensitization program and subsequently
could tolerate IFA stings without difficulty.
However, he was stung by a wasp and died in
shock 30 minutes later. There was a child-
hood history of bee and wasp stings without
difficulty.
Comment: The incidence of associated
bee and wasp sting hypersensitivity is higher
among IFA-sensitive patients than in the
normal population. Desensitization pro-
grams are effective in reducing the severity
of reactions in IFA-sensitive patients.
These programs will lessen the sensitivity to
IFA stings, but not to bee or wasp stings if
the patient is also sensitive to these insects.
Casein
An 81-year-old male was found comatose
on a fire ant mound in a field near his home
and taken to an emergency room. He had
multiple bites of the trunk, face, extremi-
ties, and genital!a. Live ants were found in
his mouth and nose. The man was intubated
and placed on assisted ventilation. Fire ants
were recovered from the trachael intubation
tube and from uretheral catheter drainage.
He was admitted to an intensive care ward
to the care of a physician who felt that the
patient had a stroke. The patient was
completely well the day following admission
and the diagnosis was revised to anaphylaxis
to fire ant stings.
Comment: Some elderly patients are
hospitalized because of shortness of breath,
and shock which is attributed initially to
heart disease. The correct diagnosis usually
is made the day following admission when
the characteristic pustules are noted.
Case IV
A 25-year-old female was stung by ants
in Hattiesburg, Mississippi. She developed
immediate wheezing and confusion, followed
by shock. She was taken to an emergency
room where she was intubated and placed on
assisted ventilation in an intensive care
ward. She recovered and was discharged.
She moved to St. Petersburg, Florida,
where she again was hospitalized for a
severe reaction to a fire ant sting.
Comment: There appear to be no geo-
graphical differences in the severity of fire
ant hypersensitivity reactions.
Case V
This 4-year-old child has experienced
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121
four episodes of hives, facial swelling, and
wheezing after fire ant stings. These reac-
tions have required emergency room treat-
ment. Subsequently, her parents do not
allow her to play outdoors for fear of
future stings.
Comment: Fire ant sensitivity is a spec-
ial problem in young children who are unable
to avoid fire ants in outdoor play.
Case VI
This 63-year-old male tourist from Min-
nesota with known angina pectoris devel-
oped severe chest pain, hives, and shortness
of breath after a fire ant sting. He was
hospitalized in a coronary care unit where
he recovered uneventfully.
Comment: A hypersensitive reaction to
a fire ant sting in a patient with underlying
cardio-vascular disease can be a fatal event.
REFERENCES
Schmid, W. 1977. Medical implications:
imported fire ants, Solenopsis invicta.
Cutis 19(June).
James, F. K. Jr., H. L. Pence, D. J. Driggers
et al. 1976. Imported fire ant hypersen-
sitivity: studies of human reactions to
fire ant venom. J. Allergy Clin.
Immunol. 58:110.
Rhodes, R. B., W. L. Schafer, W. H. Schmid
et al. 1975. Hypersensitivity to the
imported fire ant. J. Allergy Clin.
Immunol. 56:84.
Caro, M. R., V. J. Derbes, R. Jung: Skin
responses to the sting of the imported
fire ant (Solenopsis saevissima). Arch.
Dermatol. 74:475.
SUMMARY
In infested states, a hypersensitive reac-
tion to a fire ant sting should be suspected
when a patient is seen with unexplained
acute hives or shock. Complications from
IF A stings cause considerable medical
expense, human morbidity, and occasional
mortality. Until an acceptable means of
control is developed, physicians practicing
in the infected areas can expect to treat
many complications from the sting of the
insect.
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APPENDIX C
A BRIEF HISTORY OF CHEMICAL CONTROL OF THE IMPORTED FIRE ANT
R.L. Metcalf
PANEL IV
INTRODUCTION
The development of chlordane in 1944
(Kearns et al. 1946) provided the first effec-
tive synthetic organic insecticide against
ants (Formicidae). Chlordane (1,2,4,5,6,7,8,
8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-
methanoindene) became the standard
remedy for controlling ants about premises-
-a position it occupies today. Chlordane is
synthesized from cyclopentadiene which is
the reactive raw material that became the
base for a variety of other cyclodiene
insecticides including heptachlor
(l,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahy-
dro-4,7,-methanoindene) and dieldrin (1,2,
3,4,10,10-hexachloro-6,7-epoxy-l,4,4a,5,6,7,
8,8a-octahydro—endo-l,4-earo-5,8-dimetha-
nonaphthalene). These compounds were sev-
eral times more toxic to ants than chlor-
dane. Dieldrin, as an epoxide, was environ-
mentally the most stable and persistent.
Heptachlor, because of its C,=Co, could be
oxidized environmentally and biochemically
to form heptachlor-2,3-epoxide—an even
more toxic compound whose environmental
persistence rivaled that of dieldrin.
The availability of these effective and
highly persistent formicides coincided with
the expansion of the imported fire ant's
(IFA) area of infestation (SoZenopsis invicta)
(Buren et al. 1974). Heptachlor and dieldrin
were seen as the most promising weapons
for area-wide IFA control programs.
HEPTACHLOR AND DIELDRIN
With ample funding from Congress, the
USD A undertook a massive IFA eradication
program covering millions of acres in Flor-
ida, Georgia, Alabama, Louisiansa, and Tex-
as. The plan was to treat all infested lands
with 20 Ib. of 10% granular heptachlor or
dieldrin per acre. This dosage [2 Ib Al
(active ingredient)] was considered suffi-
cient to eradicate the IFA and to prevent
reinfestation of the treated area for a mini-
mum of three years. This treatment was
conducted for two years with heptachlor
being used more extensively than dieldrin.
Heptachlor and dieldrin are environ-
mentally persistent and toxic to terrestrial
and aquatic wildlife (Pimentel 1971), yet
little consideration was given to the
environmental hazards of these chemicals to
non-target organisms, and the eradication
program had virtually no research compo-
122
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123
nent to examine such hazards. Damage to
wildlife in the treated areas was immense.
As a result, at the start of the third year of
the eradication program, treatment rates
were reduced to 1.25 Ib. technical hepta-
chlor per acre. Experiments were con-
ducted with two 0.25 Ib per acre treatments
at a three month interval.
Wildlife studies in Hardin County, Texas,
showed that opposums, armadillos, and an
abundant racoon population virtually disap-
peared and were still depressed during the
second season after treatment with hepta-
chlor. Racoons that repopulated the area
were contaminated with heptachlor epoxide
residues in the kidney averaging 19.9 ppm
(parts per million) after two weeks, 3.8 ppm
after six months, 7.8 ppm after nine months,
and 4.5 ppm after one year (DeWitt and
George 1960). Birds were particularly
devastated. Evaluations showed that in
Texas and Louisiana the bird population de-
clined over 85% following treatment; nest-
ing successes were reduced by 89% or more
and remained depressed the following year.
Ground birds were severely affected (Tables
1 and 2).
Dead animals found within three weeks
after treatment in areas of Texas, Louisi-
ana, Alabama, Georgia, and Florida were
analyzed for total body residues of dieldrin
or heptachlor epoxide. More than 98% of
the dead animals contained detectable resi-
dues. These were highest in a wide variety
of birds whose averagebody residues were
(1) dieldrin: 17.9 ± 4.3 ppm (18 species) and
(2) heptachlor epoxide: 15.3 ± 8.6 ppm (30
species). Residues were found in a variety
of mammals, fish, reptiles, and amphibia
Table 1. Reduction of ground birds in
Montgomery County, Alabama,
1959, following heptachlor or
dieldrin treatments for imported
fire ant control.
Strata
Reduction
low or ground (7 species) 100%
low to intermediate (17 species) 50-99%
intermediate to high (19 species) no effect
Table 2. Surveys of birds seen in Wilcox
County, Alabama, following
treatment for imported fire ant
control.
Treatment Live Birds Seen Per Mile
heptachlor
heptachlor
dieldrin
untreated
Robins
0.0
6.0
0.0
22.8
Meadowlarks
0.2
0.0
0.0
25.7
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124
(DeWitt et al. 1960). Where granular appli-
cations were made to salt marshes and other
aquatic areas, the fish populations were
eliminated or seriously damaged.
The extensive damage to wildlife from
the IF A eradication program alarmed con-
servationists. Rachel Carson (1962) de-
scribed the program as ill conceived, badly
executed, and a thoroughly detrimental ex-
periment in insect control that resulted in
both the destruction of animal life and in
loss of public confidence in the USDA. She
found it incomprehensible that any public
funds were still devoted to it. The misuse
of heptachlor and dieldrin in the early
stages of the IF A eradication program was a
critical part of the accumulated environ-
mental outrage that created Silent Spring
and resulted in public disenchantment con-
cerning the widescale use of pesticides.
About 20 million acres were treated dur-
ing the five years of the early eradication
program. From 1957 to 1962 however, the
area infested by IF A had increased from 90
million acres to about 126 million acres
MIREX
In the search for a more ecological way
to control IFA, many synthetic organic
chemicals were evaluated. Hays and Arant
(1960) at Auburn University showed that
peanut butter baits containing 0.125% chlor-
decone (Kepone) (1,2,3,5,6,7,8,9,10,10-
dodecachlorooc tahydr o-1,3,4-m et heno-2 H-cy-
clobuta-[ccfl-pentalen-2-one) (another cyclo-
diene product of hexachlorocyclopentadiene)
gave excellent IFA control. The USDA
Methods Development Laboratory at Gulf-
port, Mississippi found that a very closely
related cyclodiene, mirex (1,2,3,4,5,5,6,7,8,-
9,10,10-dodecachloro-octahydro-l,3,4-me-
theno-2H-cyclobuta-[c,cfl-pentalene) was as
effective as chlordecone and was less toxic
to non-target species (Lofgren et al. 1962).
An IFA bait formulation was developed
consisting of once-refined soybean oil as
food, corncob grits as carrier, and mirex as
toxicant. The bait was effective at rates as
low as 4.2 grams of mirex per hectare (1.7
grams per acre). During development it was
found that increasing the mirex content
from 0.075% to 0.3% substantially reduced
the bulk rate of application. This bait,
properly applied, averaged 98% control of
IFA from ground applications and 96% con-
trol on large acreages treated by aircraft
(Lofgren et al. 1975). In 1962, 0.3% mirex
bait became the standard IFA control agent
(Alley 1973).
Mirex had a delayed stomach poison
action that appeared ideal for IFA control.
Its properties included: (1) delayed killing
action over a 10 to 100 fold dose range, (2)
easy transfer between ants through regurgi-
tation, resulting in death of the recipient,
often the queen, and (3) attractiveness to
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125
the IFA (Waters et al. 1977). Secretary of
Agriculture Orville Freeman hailed mirex as
the perfect pesticide. "It has no harmful
effect on people, domestic animals, fish,
wildlife, or even bees, and it leaves no
residue in milk, meat, or crops" (Whitten
1966, Science 1971).
Armed with mirex, the USDA planned a
massive eradication program that included
all 126 million acreas infested by the IFA.
The program was to be conducted over a 12
year period at a cost of $200 million that
would be financed as a matching fund opera-
tion between the USDA and the partici-
pating states. Subsequently, a National
Academy of Science Committee (Mills 1967)
reported that eradication of the IFA was
biologically and technologically impossible
and was inadvisable if it were possible.
USDA eradication trials conducted with the
mirex bait (Banks 1972), however, were in-
terpreted as demonstrating the feasibility of
eradication with three or four sequential
applications of the mirex bait.
In retrospect, mirex is far from the
"perfect insecticide." Mirex contains no
carbon-hydrogen bonds and is one of the
most environmentally stable xenobiotics
known. Mirex was first synthesized by
McBee et al. (1956) and was patented as an
insecticide (Belgium pat. 624, 256, April 30,
1963, French pat. 1,338,074, September 30,
1963) and, because of a melting point of
349°C, as a flame-retardant (U.S. Pat. 3,-
494,973, February 10, 1970). Mirex is sol-
uble in water to about 20 ppb and has an
octanol/H20 partititon coefficient of about
10,000. In laboratory model ecosystem
studies, (Metcalf et al. 1973), 14C mirex
shown to bioaccumulate through food chains
and to persist, virtually undegraded, in alga,
mosquito larva, snail, and fish (98-99% par-
ent compount). Rats eliminated 18% of 14C
mirex as unmetabolized mirex; the re-
mainder was stored in body tissues (Gibson
et al. 1972).
The use of mirex was followed by evi-
dence of its persistence and biomagnifica-
tion. In an area of Louisiana that had
received six applications of mirex bait at
1.25 Ib. per acre over a four year period the
following residues were found: 0.01 to 0.75
ppm in snails, crayfish and fish; 1.2 to 1.91
ppm in birds; 24.82 ppm in the fat of soft-
shell turtles; and 73.94 ppm in the adipose
tissue of vertebrates at the top of the food
chain (Hyde et al. 1973). In an estuarine
environment, mirex in the water at 0.5 ppb
was found to bioaccumulate to 20.4 ppm in
minnows (40,800X), to 5 ppm in shrimp
(10,OOOX), and to 1.5 ppm (2,300X) in blue
crabs (Tagatz et al. 1975). A survey of birds
from South Carolina, Georgia, and Florida
showed an average value of 4.32 ppm (liquid
weight) of mirex in eight birds (Dreitzer
1974), while starlings contained levels of 0.1
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126
to 1.66 ppm (Oberhen 1972). Adipose tissues
of persons living in treated states were
found containing mirex in amounts ranging
from 0.16 to 5.94 ppm (Kutz et al. 1974).
More recently mirex residues were found in
23% of adipose tissues from 624 inhabitants
of eight southern states (EPA 1980, Severn
1982-Appendix F).
As a result of these disclosures, the
Environmental Defense Fund (EDF) brought
suit in August 1970 to terminate the USD A
IFA program. The EPA issued a cancella-
tion order for the use of mirex, effective
March 18, 1971. Allied Chemical Company,
the sole manufacturer of mirex, protested
the cancellation. Following hearings, the
EPA issued new guidelines for a modified
control program. However, entomologists in
many of the cooperating states began oppos-
ing the program, and the eradication pro-
gram began to die when several states with-
drew their matching support (Shapley 1971).
Meanwhile, additional concerns had de-
veloped about the continued use of mirex.
Approximately 3,361,000 Ib. of mirex were
manufactured at Niagra Falls, N.Y. between
1959 and 1975. Mirex-containing effluents
from manufacturing and waste disposal con-
taminated the southern waters of Lake On-
tario with concentrations from 1 to 10 ppb.
A variety of fish from the lake contained
whole-body residues of mirex, with mean
levels of: white perch 0.10, smelt and small
mouth bass 0.13, coho salmon 0.17, Chinook
salmon 0.21, and lake trout 0.22 ppm. The
maximum level recorded was 1.20 ppm.
Residues of mirex were found in the eggs of
herring gull, cormorant, gyrfalcon, prairie
falcon, peregrin falcon, and pigeon hawk. In
the pigeon hawk, these residues had a mean
value of 0.25 ppm and ranged from 0.01 to
3.16 ppm (Kaiser 1978).
Mirex undergoes slow environmental de-
gradation by both photochemical and micro-
biological processes and forms two monohy-
droderivatives (C^HCl.,), two dihydro—
derivatives (c10H2C1i(J' and cnlordecone
(Kepone*), the 2-C=0 derivative (C1()C1100).
Alley et al. (1974a,b) explored the photo-
chemistry of mirex and chlordecone.
Samples of mirex fire ant bait exposed to
the elements for five years contained 75.9
to 81% of mirex, 7.4 to 8.3% mono-hydro
mirex or photomirex, and 1.3 to 5.7% chlor-
decone (Carlson et al. 1976). Concern over
the formation of chlordecone from mirex
was heightened by the Hopewell, Virginia,
experience where the James River and much
of Chesapeake Bay were contaminated with
an estimated 100,000 Ib. of chlordecone
(Kepone) effluent. Factory workers
suffered reproductive difficulties due to the
estrogenic properties of this substance and
developed severe symptoms of delayed
neurotoxicity (Sterrett and Boss 1977).
Mirex and chlordecone were found to be
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127
animal carcinogens. Lifetime feeding of
mice with mirex at 26 ppm in the diet
produced liver hepatomas in 45% as com-
pared to 4% of the control mice (Innes et al.
1969). Lifetime feeding of mice at 20 to 40
ppm with chlordecone produced hepatocellu-
lar carcinomas in 81 to 88% of males and 47
to 52% of females compared to 16% in male
controls and 0% in female controls (National
Cancer Institute 1976).
Due to the continued concern over public
health and environmental quality aspects of
the large scale deployment of mirex bait,
EPA banned the use of mirex. As a result,
Allied Chemical Company sold its plant in
Aberdeen, Mississippi, to the state for $1.
Mississippi then established an Authority for
the Control of the Fire Ant within the
Department of Agriculture and Commerce.
In October 1976, EPA and Mississippi agreed
to terminate aerial application of mirex
baits by December 31, 1977, and to permit
ground applications only through June 30,
1978. At that time the pesticide registra-
tion of mirex was cancelled.
Studies of the photodegradation of mirex
showed that environmental dechlorination to
photomirex and to further dechlorination
products could be accelerated by adding
aliphatic amines and ferrous chloride (Alley
et al. 1974c). An IFA bait formulation
ferriamicide, was developed to contain
0.05% mirex, 1.7% amine (Keramine T
1902D), 0.2 ferrous chloride hexahydrate,
and 8% soybean oil. This formulation is to
be applied at 1.5 Ib per acre equivalent to
0.227 grams mirex per acre. The ferriami-
cide formulation reduces the environmental
half-life for mirex from 12 years to about
0.15 years (Alley 1982-Appendix F). Con-
cern over the production of the highly toxic
photomirex as a principal degradation pro-
duct has delayed registration of ferriami-
cide by EPA.
In order to avoid the persistent and non-
degradable residues of the organochlorine
insecticides, efforts were made to find more
biodegradable organic stomach poisons.
USDA scientists screened more than 5000
candidate pesticides and the most promising
substitute for mirex found during the 1970's
was tetrahydro-5,5-dimethyl-2-(lH)-pyrimi-
done-[3-(4-trifluoromethyl)-phenyD-l[2-(4-
trifluoromethylphenyD-ethenyD-2-propenyli-
dene-hydrazone (trade name Amdro* Willi-
ams et al. 1980. Amdro is a slow acting
stomach poison with very low water solu-
bility, 5-7 ppb, and a low octanol/H0O parti-
£t
tion. It is of low acute toxicity and appears
to be essentially non-bioaccum illative and
environmentally degradable. Amdro is ef-
fective against IFA at 4 to 6 grams per acre
when applied in a 1% soybean oil-corn grits
bait. Amdro was registered conditionally
for IFA control by EPA in 1980 and is
available to the general public.
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128
REFERENCES
Alley, E. G. 1973. Use of mirex in control
of the imported fire ant. J. Environ.
Qual. 2:52-61.
Alley, E. G. and B. R. Layton 1974a.
Identification of insecticide photopro-
ducts by mass spectrometry. In: R.
Haque (ed.). Mass Spectrum. NMR
Spectros. Pestic. Chem., Proc. Symp.
1973, Plenum, N.Y. pp. 81-90
Alley, E. G., B. R. Layton, and J. T.
Minyard, Jr. 1974b. Identification of
the photoproducts on the insecticides
mirex and Kepone. J. Agr. Food Chem.
22:442-445.
Alley, E. G., B. R. Layton, and J. P.
Minyard, Jr. 1974c. Photoreduction of
mirex in aliphatic amines. J. Agr. Food
Chem. 22:727-729.
Barbs, W. A., B. M. Glancey, C. E. Stringer,
D. P. Jouvenaz, C. S. Lofgren, and D. E.
Weidhaas 1973. Imported fire ants:
eradication trials with mirex bait. J.
Econ. Entomol. 66:785-589.
Buren, W. F., G. E. Allen, W. H. Whitcomb,
F. E. Lennartz, and R. N. Williams.
1974. Zoogeography of the imported fire
ants. J. N.Y. Entomol. Soc. 82:113-124.
Carlson, D. A., K. D. Konyha, W. B.
Wheeler, G. P. Marshall, and R. G.
Zaylskie 1976. Mirex in the environ-
ment: its degradation to Kepone and
related compounds. Science. 194:939-
941.
Carson, Rachael 1962. Silent Spring.
Riverside Press, Cambridge, Mass. p.
162.
CAST. 1976. Fire ant control, 2nd ed.,
Council for Agricultural Science and
Technology, Rept. No. 65, Ames, Iowa.
DeWitt, J. B. and J. L. George. 1960.
Pesticide-wildlife research 1959. Fish
and Wildlife Ser. Cir. 84. 36 pp. Jan.
DeWitt, J. B., C. M. Menzie, V. A.
Adomaites, and W. R. Reichel. 1960.
Pesticidal residues in animal tissues.
Trans. 25th N. Amer. Wildlife Confer-
ence, 277.
EPA. 1982. Unpublished pesticide moni-
toring data. U.S. Environmental Protec-
tion Agency.
Gibson, J. R., G. W. Ivie, and H. W.
Donough. 1972. Fate of mirex and its
major decomposition products in rats. J.
Agr. Food Chem. 20:1246-1248.
Hays, S. B. and F. S. Arant. 1960. Insec-
ticidal baits for the control of the im-
ported fire ant. J. Econ. Entomol.
53:188-191.
Hyde, K. M., J-. B. Graves, J. F. Fowler, F.
L. Bonner, J. W. Impson, L. D. Newsom,
and J. Haggard. 1973. Accumulation of
mirex in food chains. La. Agr. Exp. Sta.
Bull. 17(1):10-11.
Innes, J. R. M., B. M. Ulland, M. G. Valerio,
L. Petrucelli, L. Fishbein, E. R. Hart,
A. B. Pallotta, R. R. Bates, H. L. Falk,
J. J. Gart, M. Klein, I. Mitchell, and J.
Peters. 1969. Bioassay of pesticides and
industrial chemists for tumorigenicity in
mice: a preliminary note. J. Nat.
Cancer Inst. 42:1101-1114.
Kaiser, K. L. E. 1978. The rise and fall of
mirex. Environ. Sci. Technol. 12:520-
528.
Reams, C. W., L. Ingle, and R. L. Metcalf.
1946. A new chlorinated hydrocarbon
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668.
Kreitzer, J. F. 1974. Residues of organ-
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(polychlorinated biphenyls) in morning
doves from eastern United States. 1970-
1971. Pestic. Monit. J. 7(314):195-199.
Kutz, F. W., A. R. Yobs, W. G. Johnson, and
G. B. Wiersma. 1974. Mirex residues in
human adipose tissues. Environ. Ento-
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Lofgren, C. S., C. E. Stringer, and F. J.
Bartlett. 1962. Imported fire ant toxic
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Lofgren, C. S., W. A. Banks, and B. M.
Glancey. 1975. Biology and control of
imported fire ants. Ann. Rev. Entomol.
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McBee, E. T., C. W. Roberts, J. D. Idole,
Jr., and R. H. Earle, Jr. 1956. An
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and C. K. Schuth. 1953. Model ecosys-
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Health Perspect. 4:35-44.
MiUs, H. B. 1967. Report of Committee on
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Research, USD A, Washington, B.C. 15
pp.
National Cancer Institute. 1976. Report on
carcinogenesis bioassay of technical
grade chlordecone (Kepone), Bethseda,
Maryland, Jan.
Oberheu, J. C. 1972. Occurrence of mirex
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eastern states, 1970. Pestic. Monit. J.
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Pesticides on Non-Target Species. Exec.
Office President, Office of Science
Technology, Wash., D.C. 220 pp.
Shapley, D. 1971. Mirex and the fire ant:
decline in fortunes of "perfect" pesti-
cide. Science. 172:358-360.
Sterrett, F. S., and C. A. Boss. 1977.
Careless kepone. Environment. 19(2):30-
37.
Tagatz, M. E., P. W. Borthwick, and J.
Forester. 1975. Seasonal effects of
leached mirex on selected estuarine ani-
mals. Arch. Environ. Contam. Toxicol.
3:371-383.
Waters, E. M., J. E. Hugg, and H. B.
Gerstener. 1977. Mirex, an overview.
Environ. Res. 14:212-222.
Whitten, J. L. 1966. That We May Live.
Van Nostrand, Princeton, N.J. p. 115.
Williams, D. F., C. S. Lofgren, W. A. Banks,
C. E. Stringer, and J. K. Plumley. 1980.
Laboratory studies with nine amidino-
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Pimentel, D. 1971. Ecological Effects of
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APPENDIX D
IMPACT OF THE IMPORTED FIRE ANT CONTROL PROGRAMS ON WILDLIFE AND
QUALITY OF THE ENVIRONMENT
Maureen K. H inkle
PANEL IV
EARLY SPRAY PROGRAMS
In 1957, the USDA created a furor
among scientists and conservationists when
it unvieled its plans for eradicating the
imported fire ant (IFA). Objections to the
program centered on the use of the chlori-
nated hydrocarbon compounds heptachlor
and dieldrin. Ezra Taft Benson, then Secre-
tary of Agriculture, was asked to delay the
program until some research could be con-
ducted (1) to determine appropriate dosages
and (2) to determine the effects of the
compounds on non-target organisms. De-
spite these objections, in 1958 the USDA
initiated the eradication program (see Table
1) with a $3 million appropriation from
Congress.
Ground applications of heptachlor and
dieldrin killed the IFA though not as well as
had been forecast; however, they also ad-
versely impacted the surrounding wildlife.
The 1971 President's Study on the Ecological
Effects of Pesticides on Nontarget Species
described the effects of heptachlor:
In 1957 the U.S. Department of
Agriculture in a cooperative program
with the States treated approximate-
ly 27 million acres in the Southeast
with heptachlor at a rate of 2 Ib/A
for control of the imported fire ant
(Smith and Glasgow, 1963). Investi-
gations of the effects of heptachlor
on wildlife were initiated after the
second year of treatment in south-
central Louisiana. On 4 farms the
following animals died within 3 weeks
after treatment: 53 mammals, in-
cluding 12 species; 222 birds, includ-
ing 28 species; 22 reptiles, including
at least 8 species; many species of
frogs; many kinds of crayfish; and
many fish, including 8 species.
Ninety-five percent of the dead ani-
mals were analyzed, and all con-
tained some heptachlor.
Quail populations in Georgia de-
clined significantly soon after the
land was treated with heptachlor at a
rate of 2 Ib/A, and the populations
had not yet recovered after a period
of 3 years of no further treatment
(Rosene, 1965). A decline of cocks
and coveys of quail also followed the
1/2-lb heptachlor applications (signi-
ficant for cocks, approaching statis-
tical significance for coveys). A
small 4-acre plot within the treated
area was searched for dead and dying
animals and observations were made
on living animals. Forty-seven days
after treatment, no live animals were
seen or heard on the plot, and a total
of 38 dead animals had been found.
A 2-year study carried out to de-
termine the effects heptachlor treat-
ments were having on bird popula-
130
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131
tions in Mississippi disclosed that all
treatment rates of heptachlor at
0.25, 0.50, and 2.00 Ib/A "decimated
arthropod populations, caused bird
mortality, and altered bird behavior
patterns." None of the dosages, how-
ever, eradicated the imported fire
ants as planned.
In Silent Spring (1962), Rachael Carson
described treated areas where all wildlife
had been destroyed. Carson also reported
deaths of poultry, livestock and domestic
pets due to heptachlor, and she cited Otis L.
Pointevint a veterinarian from Bainbridge,
Georgia, who had treated animals within a
period of two weeks to several months after
the treatment. The animals had lived in
areas that were treated for IF A and had
access to contaminated food or water.
Every animal suffered from a sometimes
fatal disease of the nervous system. Five
months after the application, one two-
month-old calf was found with 79 ppm of
heptachlor in its adipose tissues.
NEW CHEMICALS
In 1960, the FDA cancelled tolerances
for heptachlor residues in pasture grasses
and began exploring other chemicals. The
first chemical used was chlordecone (ke-
pone) in peanut butter (Texas A&M 1981).
Chlordecone, however, was highly toxic to
mammals. Research soon turned up mirex,
an analog of chlordecone, which was effec-
tive against the IF A but less toxic than
chlordecone. Mirex appeared to be the ideal
chemical control for the IFA. Foraging
workers carried the toxicant back to nesting
queens, thus insuring the death of the col-
ony. Mirex bait was comprised of 0.3%
mirex as toxicant, 14.7% soybean oil as
solvent and food, and 85.0% corncob grits as
carrier. In 1962 this bait, known as mirex
4X, was applied over a large acreage in
Georgia, Louisiana, Alabama, and Texas, at
the dosage rate of 10 pounds of product per
acre. Mirex was soon found to be effective
at lower dosages. In 1963, the dosage
dropped to 2-1/2 pounds of product per acre.
In 1965, the dosage went to 1-1/4 pounds of
product per acre. Belief in mirex's ability
to eradicate the IFA was high. Some felt
that three properly timed applications of
mirex (1-1/4 pounds of product per acre or
5.1 grams of mirex per acre) over a 1-year
to 18-month interval "to the entire infested
area would almost eliminate the imported
fire ant from the United States" (USDA
1971). This hypothesis encouraged those
who favored eradication, and in 1967 the
Senate Appropriations Committee directed
USDA to determine the feasibility of eradi-
cating the IFA with mirex (see Table 2).
Accordingly, three large-scale eradication
trials were begun.
ENVIRONMENTAL CONCERNS
With the passage of the National Envi-
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132
ronmental Policy Act (NEPA) by Congress in
1969, environmental issues found greater
emphasis. The NEPA required environment-
al issues to be considered early in the deci-
sion-making process rather than after the
fact. In 1970, the Environmental Protection
Agency (EPA) was created, and pesticide
registration moved from USDA to EPA. At
the same time, Interior Secretary Hickel
removed federal land from the mirex/IFA
program.
In addition, the newly formed Environ-
mental Defense Fund (EOF), the first envi-
ronmental group formed to bring court suits
on environmental problems and the organi-
zation that participated in several pesticide
cancellation proceedings throughout the
'70's decade, sued USDA to restrain the IF A
eradication program. The December 3,
1970, settlement called for an environment-
al impact statement (EIS), completed Jan-
uary 22, 1971. In the EIS, USDA stated that
eradication might be technically feasible,
but logistic and financial limitations to-
gether with "possible adverse environmental
effects resulting from such large-scale use
of Mirex bait" made eradication "no longer
an objective of the Federal-State Coopera-
tive Control program." The three large-
scale eradication trials had failed to erad-
icate the IF A.
USDA consequently altered the IF A con-
trol program:
Mirex bait will be applied aerially
to those areas where the ant is caus-
ing trouble, where the property own-
ers have expressed concern, and
where the State and local govern-
mental agencies have requested Fed-
eral cooperation in a control pro-
gram. Under the plan, forested areas
which are not prime fire ant habitat
and sensitive areas such as estuarine
area's, and State and Federal game
refuges will not be treated. Applica-
tion pilots will be briefed with re-
spect to all sensitive areas, including
water, and instructed to avoid appli-
cation to those areas. Compliance
will be closely monitored by ground
personnel and aerial supervision (EIS
1971) (emphasis added).
In response to questions posed by the
Appropriations Committee, USDA offered
the following definitions:
1. How do we define prime wildlife
habitat?
With respect to the imported fire
ant control program, prime wild-
life habitat is described as Feder-
al and State game refuges,
estuary and marsh areasr wooded
areas bordering streams, rivers,
and other bodies of water. Heavi-
ly wooded areas are not treated
because they do not support im-
ported fire ant populations (em-
phasis added).
2. What is the largest continuous
block that would be treated under
this one treatment concept?
In open general farming areas
without streams or heavily wood-
ed areas, 50,000 or more contig-
uous acres may be treated. As a
general guideline, if 75 percent or
more of the area is open, an elec-
tronic guidance system is em-
ployed. Cutouts such as rivers,
heavily forested areas, and game
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133
refuges are marked on the pilot's
map, and the recording tape in
the aircraft marks these areas
that are cut out. When less than
75 percent of the total area is to
be treated, small aircraft are
used due to the many cutoffs re-
quired.
3. What do we plan to do along the
peripheral areas?
Treatments are planned in peri-
pheral areas when there is threat
of spread to uninfested States or
to a new area of an infested
State. These treatments are to
be made in support of the Federal
quarantine (EIS 1971).
PROBLEMS WITH MIR EX
On March 18, 1971, within two months of
USDA's environmental impact statement,
EPA announced its intention to cancel mirex
due to the adverse effects on wildlife and
humans. Allied Chemical Company, the
registrant of ten of the eleven pesticide
products containing mirex, referred the
issue to the National Academy of Sciences.
From this came the National Research
Council's (NRC) report citing adverse ef-
fects from mirex on aquatic life, particu-
larly young shrimp and blue crabs. EPA
accepted the NCR's recommendation and
prohibited the use of mirex in coastal areas.
(This prohibition was modified June 30,
1972, to permit applications to streams and
farm ponds not used primarily for human
consumption.) Combined with Interior's ban
on federal lands, the restrictions posed dif-
ficulties since all affected states bordered
the Atlantic, the Gulf, or major rivers and
aquatic areas.
A Notice of Intent to hold a hearing on
whether or not to cancel registrations of
mirex was published April 4, 1972. Hearings
began July 11, 1973, and continued until
March 28, 1975, when settlement negotia-
tions began. On July 14, 1975, Allied with-
drew from negotiations and announced it
would stop producing mirex until an agree-
ment could be reached. Hearings resumed
sporadically until February 12, 1976, when
Allied stated it would no longer formulate
mirex bait.
On February 26, 1976, hearings were
temporarily suspended. On May 10, 1976,
Allied transferred registrations to Mississip-
pi. The hearings were dormant while Missis-
sippi reviewed the record (13,000 pages of
transcript, over 200 exhibits, testimony of
over 100 witnesses).
After reviewing the record, Mississippi
submitted a plan to phase out mirex regis-
trations and suspend the hearing. On Octo-
ber 20, 1976, EPA accepted the plan to
allow aerial application of mirex through
December 31, 1977, and ground broadcast
and mound application through June 30,
1978.
The impact of the IF A control programs
on wildlife and the quality of the environ-
ment is summaried from EPA's decision of
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134
December 29, 1976:
Impurities and Degradation Pro-
ducts. Very recent screening anal-
yses of formulated Mirex bait at the
Mississippi Authority's formulating
plant in Aberdeen, Mississippi, have
shown that Kepone is present in
Mirex bait at levels up to 0.25 ppm
and in technical Mirex at levels up to
2.58 ppm.
Recent research conducted by the
United States Department of Agri-
culture and others has shown that as
much as 10% of Mirex applied in the
environment either begins as Kepone
or is degraded into Kepone over per-
iods of fire and twelve years. . . .
Laboratory studies have shown that
Mirex can degrade photolyticly into
Kepone. . . .
Persistence.
Because of its
unique chemical structure, Mirex is
more resistent to chemical attack
than other chlorinated hydrocarbons
such as DDT, Aldrin/Dieldrin, and
Heptachlor. (Alley Testimony at 4).
Mirex therefore will likely remain on
non-living (and living) matter for
longer periods of time than would
such chlorinated hydrocarbon pesti-
cides as DDT, Aldrin/Dieldrin, and
Heptachlor. (Alley Testimony at 4).
Research performed by USDA and
others has shown that as much as
50% of the original Mirex that was
applied in 1962 was recovered from
soil residues twelve years after
treatment. . . .
Bioconcentration. Unlike most
chemical compounds (Livingston
Testimony (n) at 1), Mirex continues
to accumulate to higher and higher
levels in the brain, muscle, liver,
skin, and subcutaneous tissues of
mammals to which it is fed as a
constant increment of the diet, ap-
parently without reaching a plateau.
There appears to be an unlimited
capacity for accumulation of Mirex
in some animal tissues, and Mirex can
accumulate in vertebrate animals to
extremely high levels. (Gibson Testi-
mony at 3; Gibson TR 157, 165, 168).
Moreover, Mirex accumulates in
wildlife and the food of wildlife, in-
cluding Crustaceans, . . . Ciliate pro-
tozoa, . . . .and algae. ... At even
the most primary trophic levels in
the environment the bioconcentration
of Mirex has been demonstrated, of-
ten at levels thousands of times that
found in aquatic media.
In addition, Mirex is highly resis-
tant to metabolic attack, and as a
consequence is apparently not elimi-
nated from vertebrate bodies as a
result of metabolic conversion . . .
nor is it readily excreted through
normal excretory channels. . . .
However, Mirex can be excreted
through special mechanisms, such as
lactation and via egg yolks. (Refer-
ence 4 at 5-7; Kimbrough Testimony
at 9). The significance of these
special pathways of Mirex elimina-
tion is two-fold. First, man is a
consumer of products which are the
vehicles of such special elimination
in other species. Second, since it has
been shown that cows will eliminate
significant quantities of Mirex in
their milk, it is reasonable to expect
that Mirex will also be excreted in
the milk of female human beings and
thus transmitted to their offspring
via breast feeding. .. .
Mirex is transferred through the
placenta in rates. The placenta con-
stitutes a barrier between the fetus
and the mother which is designed to
protect the fetus. Dr. Renate Kim-
brough characterized the finding in
rats as a "warning signal" that it may
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135
also take place in human beings.
(Kimbrough Testimony at 12).
Biomagnification. Mirex biomag-
nifies in higher-level organisms as it
moves up the food chain to man. . . .
Mirex's great persistence in the en-
vironment and its propensity to bio-
accumulate and biomagnify mean
that even though it is applied at
relatively small application rates, it
will be available for consumption by
humans, wildlife, and marine and
aquatic organisms for a long period
of time. (Alley Testimony at 4;
Plapp Testimony at 10-11).
Non-target insects. Tests have
shown that one application of 0.018
pounds of technical Mirex per acre
reduces the population of carabid and
staphylinid beetles by 60 percent and
67 percent respectively, (Hensley
TR2,727). These insects are among
the natural predators of the sugar-
cane borer. (Hensley Testimony at
3).
Mirex leaches from Mirex bait
into"sea water. (Tagatz Testimony at
5: Reference 11 at 4). Mirex can be
leached from Mirex bait by fresh
water, and it can thereafter enter a
salt water environment. (Tagatz
Testimony at 5). Studies have shown
that Mirex residues in water resulting
from fresh water runoff after appli-
cation of Mirex in the watershed
range from 0.1 to 1.0 parts per
trillion in fresh runoff waters. (Alley
Testimony at 7-8). Mirex is tran-
sported into aquatic organisms, in-
cluding edible fish, from nearby
treated lands. (Duke Testimony at 7,
DukeTR 1,901).
Additionally, field studies demonstrated
that mirex moved from treated land to
estuarine biota after application of mirex
bait to the Mississippi watershed and mirex
was detected in streams after heavy runoff
(Tagatz et al. 1976). Mirex was also detect-
ed in fish samples from Lake Ontario in
Canada, where it was never registered for
use (Kaiser 1974). In upper New York State,
from 0.01 to 3.16 ppm mirex residues were
detected in waterfowl.
The effects of mirex on birds received
little attention until 1977 when mirex was
aerially applied to a game management area
in Hampton County, South Carolina. In
adipose tissue of bobwhite quail, mires resi-
dues showed up to a five-fold increase with-
in the first month and peaked in the spring
following the mirex treatment, correspond-
ing with insect emergence (Kendall et al.
1977).
In addition, a study found that lesions
produced in the livers of chicks "appeared to
be related to mirex treatment" (Davison et
al. 1976). This find was significant because
lesion development was proportional to
mirex ingestion and represented irreversible
cellular damage.
Humans were not exempt from mirex
residues. In 1967, EPA analyzed samples of
adipose tissues from persons living in mirex-
treated areas and found that the percentage
of residues increased in states that had
heavy mirex treatments. Forty-four per-
cent of persons tested in Mississippi showed
positive residues of mirex compared with
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136
traces in South Carolina. The average resi-
due was 0.16 ppm with the range from trace
to 5.94 ppm. Twenty-one percent of all
samples were positive for mirex (Kutz et al.
1974).
The finding of residues in humans plus
laboratory evidence of carcinogenicity
prompted the EPA in December 1976 to
conclude that mirex posed a carcinogenic
risk to humans. Further studies showed that
mirex and kepone behaved similarly in (1)
resistance to metabolic attack, (2) failure to
be eliminated through normal excretory
channels, and (3) induction of hepatocellular
carcinomas in mice and rats.
With no mirex for aerial application
against the IFA in 1978, for the first time
since 1960, the Office of Management and
Budget reduced the IFA appropriations from
$9 million to $900,000. Congress then ap-
propriated $959,000 in FY 1978 for methods
development and monitoring activities, $1
million for quarantine, and approximately
$4,460,000 for IFA control.
FERRIAMICIDE
Ferriamicide is mirex that degrades. By
adding an amine [Keramine T 1902D] (1.7%),
ferrous chloride hexahydrate to enhance de-
gradation of the toxicant mirex (0.2%), and
soybean oil (8%), and 0.05% mirex, ferriami-
cide is mirex transformed into a different
compound. The distinction between mirex
and ferriamicide appears to be a matter of
0.025% mirex. When rnirex was phased out,
the 1976 EPA notice listed ten registrations
of mirex. Four of these were for the IFA:
Mirex 4X - 0.3% mirex (at 10 Ibs/acre
= 13.62 grams per acre)
Mirex 10:5 - 0.1% mirex (at 1 Ib acre =
0.454 grams per acre)
0.15% mirex
0.075%
Ferriamicide is:
0.05% mirex (at 1.5 Ibs/acre)
0.05% mirex (at 1 Ib/acre = 0.227
grams active ingredient per acre)
0.05% mirex (at 0.75 Ibs/acre =
0.171 grams active ingredient per
acre)
0.025% mirex at 0.25 Ibs/acre
The distinction between the mirex • and
ferriamicide formulations appears to be
0.075% mirex and 0.05% mirex (mirex at
0.1% at 1 Ib/acre uses 0.454 grams per acre,
while ferriamicide at 0.05% mirex, at 3/4ths
of a pound per acre, uses 0.171 grams per
acre).
Initially ferriamicide was developed to
prolong the use of mirex (Report of congres-
sional phone call, 8/31/76, from Sam
Thompson to D.A. Lindquist, re: "Coopera-
tive agreement on increasing rate of Mirex
degradation, Mississippi State Chemical
Laboratory."). It was believed that a 400%
reduction in mirex dosage would be ade-
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137
quate for fire ant control.
When Mississippi learned about ferriami-
cide, they applied for a Section 18 (emer-
gency exemption) to use the compound. Due
to political pressures and "the need to ob-
tain matching funds from their own legis-
latures . . . before they recess for the year"
(February 22, 1978, letter by Barbara Blum,
EPA), EPA approved the ferriamicide re-
quest despite its admission that
There has not been enough time to
develop the data on mammalian toxi-
city necessary to demonstrate human
safety, nor have questions been an-
swered about degradation products
and persistence in the field. Despite
apparently rapid breakdown and re-
duced shell fish toxicity, we cannot
say that ferriamicide is or is not safe
for humans, domestic animals and
non-aquatic species. It will take up
to 36 months to fill the data gaps
completely; a conditional registration
is possible in 12 months if pending
legislation giving the agency author-
ity for such registration is enacted
(Butler 1978).
Ferriamicide was allowed only for mound
treatment in Mississippi until July 30, 1979.
By the time a renewal request would have
been required to extend the emergency per-
mit, kepone had been found in ferriamicide
shelf samples (see Table 3).
AMDRO 217,300
In 1979, EPA approved aerial application
of a new substance to combat the IFA—
Amdro, manufactured by American Cyana-
mid. Amdro
is an amidino-hydrazone compound
that is a slow acting stomach insecti-
cide. The toxicant degrades rapidly
in the environment in sunlight with a
half life of less than 24 hours. It is
insoluable in water but is soluable in
acetone, methanol, ethanol, isopro-
panol and hot ethyl acetate. AC
217,300 reportedly does not leach in
the soil and is degraded by microor-
ganisms. It apparently does not bio-
accumulate in the environment ac-
cording to model laboratory studies. .
After four years of testing,
Amdro has been shown to be an ef-
fective toxicant against the imported
fire ant (USDA 1981).
CONCLUSION
Chemical control of the IFA is a profit-
able market. Table 1 shows how appropria-
tions increased from $2.4 million in 1958 to
$9.5 million in 1977. The years 1978 to 1980
saw no aerial applications for IFA control
and fewer dollars were appropriated. In
1981 aerial registration for Amdro was ap-
proved and $6 million were appropriated—
this from a budget-conscious Congress.
However, in such large programs, dollars
should not be a key issue. The environment-
al implications of a control program for the
IFA are great. Comprehensive management
strategies are needed, not just large-scale
chemical applications. The Audubon Society
agrees with Homer Collins, a USDA scien-
tist who said, "not enough research atten-
tion has been given to mound application
treatments for fire ant control" (USDA Fire
Ant Work Group Meeting, December 5,
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138
1978, Memo December 15, 1978, p. 3). More
dollars need to go to research to develop
effective chemicals, juvenile hormones, in-
sect growth regulators, and chitin inhibitors
for mound treatment.
The Department of Interior, commenting
on USDA's Final Programmatic EIS (May 21,
1982), criticized the USD A for continuing to
dwell "almost entirely on aerial application
over large acreages and this mode of appli-
cation causes great concern for almost all
forms of aquatic animal life" (FEIS 1981).
Von Rumker et al. (as referenced in Shoe-
maker and Harris 1974) estimated that less
than one percent of insecticide applied by
air is absorbed by insects through contact,
inhalation, or ingestion. Him el (as refer-
enced in Shoemaker and Harris 1974) des-
cribed the present system of crop spraying
as "the most inefficient industrial process
ever practiced." Clearly, we cannot afford
environmentally to spray areas millions of
acres of coastal wetlands, salt marshes,
wildlife refuges, and river areas for IF A; we
also cannot afford to use scarce public funds
for such an expensive and inefficient pro-
gram. Perhaps more dollars and effort
should concentrate on mound application
compounds, because the mound is the source
of the problem. Another concern in any
mass spray program is pesticide resistance
by other organisms and this concern should
be realistically addressed in any large spray
program.
The risks of pesticides cannot be disre-
garded. Steps have been made to make
chemical registration and use safer; how-
ever, the quantity of pesticides produced
increased 80% in the 1970's. They doubled
since Silent Spring. In the U.S. they will
double in the next 20 years and quadruple in
developing countries. As long as chemicals
must be used to protect our food sources
and ourselves, risk to the soil, non-target
species, and humans abounds.
REFERENCES
AUey, E.G. and B.R. Layton. 1976.
Aqueous photochemistry of mirex.
Paper presented at 172nd National Meet-
ing of the American Chemical Society,
San Francisco, CA, Fall.
Butler, W.A. 1978. Memorandum of Points
and Authorities in Support of Plaintiff
Environmental Defense Fund's Motion
for Summary Judgment, EOF v. Barbara
Blum, Civil Action No. 78-0577. June 8,
1978.
Carson, R. 1962. Silent Spring. Riverside
Press, Cambridge, Mass.
Council for Agricultural Science and Tech-
nology. 1976. Fire Ant Control. Report
No. 62. Ames, Iowa.
Davison, K.L., H.H. MoUenhauer, R.L.
Younger, and J.H. Cox. 1976. Mirex-
induced hepatic changes in chickens,
Japanese quail, and rats. Archives of
Environmental Contamination and Toxi-
cology 4(4):469-482.
Kaiser, C.L.E. 1974. Mirex: an unrecog-
nized contaminant of fishes from Lake
-------
139
Ontario. Science 183(4150):523-525.
Kendall, R.J., R. Noblet, J.D. Hair, and H.B.
Jackson. 1977. Mirex residues in Bob-
white quail after aerial application of
bait for fire ant control, South Carolina-
1975-1976. Pestic. Monit. J. 11(2): 64-
68.
Kutz, F.W., A.R. Yobs, W.G. Johnson and
G.B. Wiersma. 1974. Mirex residues in
human adipose tissue. Environ. Entomol.
3(5):882-884.
Shoemaker, C. and M.O. Harris. 1974. The
effectiveness of SWCPs in comparison
with other methods of reducing pesticide
pollution. Effectiveness of Soil and
Water Conservation Practices for Pollu-
tion Control, D.A. Haith and R.C. Loehr
(eds.). EPA Report-600/3-79-106.
Tagatz, M.E., P.W. Borthwick, J.M. Ivey,
and J. Knight. 1976. Effects of leached
mirex on experimental communities of
estuarine animals. Archives of Environ-
mental Contamination and Toxicology
4(4):435-442.
Texas A&M Experiment Station. 1981. The
Imported Fire Ant Program: A Search
for New Control Methods, unnumbered.
United States Department of Agriculture.
1976. Cooperative Imported Fire Ant
Program, Environmental Impact State-
ment. USDA/APHIS, Washington, D.C.
USD A. 1981. Cooperative Imported Fire
Ant Program, Final programmatic Envi-
ronmental Impact Statement. USDA/-
APHIS, Washington, D.C.
USD A. 1981. Memorandum re: Report on
Ferriamicide Bait Samples-Shelf Life
Study, to: Dr. R.L. Williamson, April 14,
1978.
USDA. 1977. ARS/APHIS Imported Fire
Ant Meeting, March 20, 1977.
USDA. 1977. ARS/APHIS Imported Fire
Ant Meeting, June 28, 1977.
USDA. 1978. Report of FR/APHIS Im-
ported Fire Ant Technical Work Group
Meeting, Raleigh, North Carolina, April
25, 1978. USDA/APHIS, Washington,
D.C.
United States Environmental Protection
Agency. 1976. Administrator's Decision
to Accept Plan of Mississippi Authority
and Order Suspending Hearing for the
Pesticide Chemical Mirex, 41 Federal
Register 56697-56704, December 29,
1976.
United States EPA. 1979. Supplemental
Opinion and Order, Under Section 18 of
the Federal Insecticide, Fungicide, and
Rodenticide Act, Use of Ferriamicide in
Mississippi, 44 Federal Register 11111-
17, February 27, 1979.
-------
Table 1. Estimated acres of D?A infestation, federal IFA appropriations, and control monies (from
USDA June 2, 1982) (in thousands).
Infested
Year Acres (Est.)
1932 200
1947 2,000
1954
1955
1956
1957
1958
1959 26,000
1960
1961
1962
1963 31,000
1964
1965
1966
1967 106,000
1968
1969
1970
1971 126,500
1972
1973
1974
1975b 135-150M
1976
1977
1978 190,000
1979
1980
1981 230,000
1982
1983C
Federal
Control
736
1,269
1,550
1,465
1,392
1,689
1.258
1,764
2,106
2,835
3,280
2,839
2,843
2,533
2,587
4,519
3,916
4,233
3,253
3,299
584
2,467
2,000
2,800
67,217
State & Local
Coop. Funds
1,506
2,302
1,844
1,420
1,343
1,735
1,896
1,864
2,076
2,002
3,524
3,730
3,720
4,271
4,671
3,533
5,696
4,812
2,184
3,770
4,710
1,394
1,315
2,650
67,968
Total
Control
2,242
3,571
3,394
2,893
2,735
3,424
3,154
3,628
4,182
4,837
6,804
6,569
6,563
6,804
7,258
8,052
9,612
9,045
5,437
7,069
5,294
3,861
3,315
5.450
125,193
Actually Spent
By APHIS*
2,088
2,437
2,610
2,546
2,529
2,967
2,446
2,977
3,910
3,249
4,530
4,595
5,295
6,361
7,108
7,047
7,180
8,708
8,545
6,823
3,529
2,467
4,303
3.852
108,102
Appropriations
2,400
2,486
2,495
2,571
2,571
2,610
2,495
3,270
3,303
5,389
4,809
5,036
5,643
7,762
7,552
7,928
7,195
9,037
9,127
9,487
1,942
1,942
1,996
6,000
115,046
5,915
120,961
Estimates 1932-71: National Academy of Sciences
Estimates 1975: CAST
Estimates 1978: Texas A & M Booklet
aAppropriated and used for survey, regulatory activities, environmental'monitoring, control eradication, and
method development work, including field tests for evaluating controls.
bFY 1975-1976 includes a transition quarter for the period 7/1/78 - 9/30/76 to new fiscal year beginning
10/1/76.
C1983 appropriation of $2,625,000 is pending approval of Congress.
140
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Table 2. Summary of pesticides used and federal action taken for IF A.
Year
Pesticide
Federal Action
1920
1946
1957
1962
1963
1964
1965
1967
1970
1971
calcium
cyanide
gasoline
chlordane
heptachlor
dieldrin
1958 2 Ibs/acre
1959
1960 heptachlor
1-1/4 Ibs/acre
mi rex
10 Ibs/acre
mirex
2-1/2 Ibs/acre
1-1/4/acre
twice/year
Congress appropriated $3 million.
Only a few states appropriated funds at first (Alabama,
Georgia, Louisiana and Florida).
Federal quarantine established in nine southern states.
Alabama stopped matching funds. USDA offered heptachlor
free to Texas landowners who signed release absolving federal,
state and local government of responsibility for damage.
FDA cancelled tolerances for heptachlor residues on pasture
grasses. (Texas and Florida also withdrew financial support for
IFA program.)
GAO (Government watchdog agency) accused USDA of
disregarding scientific opinion and wasting government funds.
Whitten overuled ARS budget cut request. Budget Bureau
pressuring reduction in budget.
President Johnson eliminated program for FY 1967. Whitten
increased appropriation. Johnson froze $2 million of the $5
million budget funds. USDA asked NAS for report which
concluded eradication not biologically or technically feasible.
IFA dramatically spread, IF As not caused significant harm to
land values, agricultural production or health.
Pesticides transferred ,from USDA to EPA. Interior Secretary
Hickel removed Interior land from mirex applications because
of harm to fish.
Approximately $800,000 diverted to extramural research and
apportioned via specific cooperative agreements to various
scientists at universities in the south. (Lofgren, Tall Timbers
Conference paper at 2.)
141
-------
Table 2. Continued.
Year
Pesticide
Federal Action
1972
1973
1977 mirex phased out
ferriamicide EUP
1978 ferriamicide Sec.
18 Emergency Use
1979 Amdro EUP
1980 Amdro conditional
registration
1981 ferriamicide
request for condi-
tional registration
National Academy of Sciences Report: mirex poses serious risk
to aquatic life, particularly young shrimp and blue crabs.
3/28/73-EPA prohibits aerial applications to coastal counties,
broadcast applications on aquatic areas and heavily forested
areas.
4/4/73-EPA Notice of Intent to hold a hearing.
7/11/73-Hearings began, continued until 3/28/75 when Allied
Chemical Company withdrew from negotiations, and announced
cessation of production of mirex until agreement reached.
6/28/77-USDA said program not as effective as previously,
because any individual who does not want mirex can request
land not be treated.
9/29/77-EPA issued experimental use permit for ferriamicide to
Mississippi for Florida and Mississippi 9/9/77 to 10/1/78.
12/16/77-Mississippi applied for emergency exemption for
aerial application of ferriamicide.
12/31/77-Mirex no longer legal by aerial application mound and
ground broadcast permitted through 6/30/78.
OMB reduced appropriations from $9 million to $900,000
because "like pouring money down a rat-hole." Treatments only
in Mississippi, Alabama, and Georgia. Rest of states decided
not to treat.
3/8/78-EPA approved emergency exemption 7/1/78 to 6/30/79.
House of Representatives defeats amendment to allow
emergency use of mirex for two years by vote of 224 to 167
(11/28/79).
Senator Talmadge directs EPA and USD A to develop a
comprehensive strategy.
142
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Table 3. History of chlordecone.
Year
Action
1960 First bait experimented with for the IFA was chlordecone (Kepone) in peanut
butter. Mirex, an analogue of chlordecone, developed.
1974 G.W. Ivie (Dorough and Alley) report that mirex converts to chlordecone.
1976 USDA reported chlordecone as degradate of mirex.
EPA finds chlordecone in mothers milk in the south.
NCI concludes chlordecone is carcinogenic in both sexes of rats and mice.
(Induces statistically significant numbers of hepatocellular proliferative lesions,
including hepatocellular carcinomas.) (January, 1976)
Mirex samples taken from Mississippi production plant contained chlordecone at
levels between 0.25 ppm and 2.58 ppm. (Pesticide Toxic Chemical News, July
28, 1976)
Alley and Layton present paper to the American Chemical Society concluding
that "direct photochemical chlordecone reactions are not a major route for the
conversion of mirex to chlordecone." (paper at 3)
6/17/76 EPA notices intent to voluntarily cancel all registered products containing
chlordecone. Final cancellation takes effect May 1, 1978.
4/6/78 Memo from the National Program Staff of notification from J.H. Ford
Laboratory Director of National Monitoring and Residue Analysis Lab that as
much as 22 ppm chlordecone was found in 54-day samples of ferriamicide bait
samples formulated at the Prairie, Mississippi Plant.
4/14/78 Memo from Dr. Williamson, APHIS, on report of shelf-life study of ferriamicide
bait samples. Fifty samples were analyzed for mirex, photodegradative studies
and chlordecone. They were divided into four categories. All ten samples of
the Series I, Day 54, bait samples had chlordecone and eight had detectable 8-
monohydromirex or photomirex.
Dr. Alley in the conversation following this discovery, told of his finding that
between 3-6% chlordecone was formed from the degradation of technical mirex
in the bait formulation. Added that "methanol or ethylene glycol would dissolve
the aliphatic amine, which will inhibit the production of chlordecone in the
mirex degradation process."
4/25/78 APHIS IFA Technical Work Group Meeting, discussed finding of chlordecone as
degradation product of ferriamicide, which "has resulted in considerable
confusion in evaluation."
143
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APPENDIX E
FERRIAMICIDE: A TOXICOLOGICAL SUMMARY
Earl L. Alley
PANEL IV
The following summarizes the discussion
on the toxicological properties and composi-
tion of ferriamicide. It is believed that
aerial broadcast of ferriamicide shows pro-
mise for effective IFA control. Aerial
broadcast application increases the effect-
iveness of ferriamicide bait or other insecti-
cidal baits and offers more complete cover-
age than mound application; therefore, rein-
festation rates are reduced. Table 1 com-
pares the large amount of toxicant required
for individual mound treatments versus that
required for broadcast treatments with
baits. Broadcast application of ferriamicide
requires only 227 mg of active ingredient
per acre, but drenches of individual mounds
require 400 to 30,000 mg per mound. Table
1 also shows that the amount of toxicant
needed for IFA control has been reduced
from 50,000 mg per acre for dieldrin/hepta-
chlor to the 227 mg recommended for ferri-
amicide.
Table 2 describes the composition and
function of the compounds in ferriamicide.
The amine and ferrous chloride components
reduce the half-life of mirex from 12 years
to about 0.15 years. Additionally, propylene
glycol suppresses the production of kepone.
During the discussion, the structure and
numbering system for mirex and its mono-
and dihydrogen derivatives were shown and
the UV spectrum of mirex, triethylamine,
and the charge-transfer complex were des-
cribed. The relationship between wave-
lengths of sunlight at the earth's surface,
the photo-chemical stability of mirex, and
the photo-chemical reactivity of ferriami-
cide also were explained. The absorption by
ferriamicide bait at wavelengths greater
than 300 nm produces a dramatic increase in
the degradation rate of the active ingredi-
ent. The dechlorination reactions of mirex
photo-chemistry in ferriamicide leads most-
ly to substitution at the 10 position. This is
important because some of the 10-substi-
tuted derivatives are labile metabolically;
because of the greater polarity of the deriv-
atives, one might expect lesser problems
with bioaccumulation and biomagnification.
Field degradation studies on a 300-fold
treatment over normal application rates
showed that after 15 weeks, about 75% of
the mirex in ferriamicide baits had degrad-
ed. After three years, only about 20% was
left. One plot located in a shaded area
showed slightly less degradation than a plot
in full sunlight.
Table 3 is an analysis of the degradates
from the field test described above. Normal
application rates produced residues that
144
-------
145
were too small to be determined by electron
capture techniques. The compounds were
confirmed by two column capillary tech-
niques, yet two were misidentified (chlorde-
cone and 8,10-syn-dihydrogen isomer). This
was shown by comparing authentic standards
of negative ion chemical ionization spectra
with these samples. This points out the
problem that arises when identities of com-
pounds have been established by comparing
gas chromatography retention times only. It
is possible, therefore, that many of the data
reported in residue monitoring of wildlife
and humans may be similarly misidentified.
This is of particular concern at concentra-
tions near the detection limit of the tech-
nique.
There has been some controversy over
the toxicity of photo-mirex and mirex.
Canadian workers had reported that photo-
mirex was 10 to 100 times more toxic than
mirex. However, a pathologist from the
EPA Pesticide Scientific Advisory Panel
found no quantitative differentiation be-
tween the toxicities of mirex and photo-
mirex. It is believed that the Canadian test
materials were impure.
The amount of mirex applied throughout
all the control programs was 450,000 kg. As
a fire retardant, 1,000,000 kg of mirex has
been used. When using ferriamicide, the
entire IFA infested area would have to be
treated ten times to use the same amount of
mirex (450,000 kg). At maximum foresee-
able rates of use, this would take about one
hundred years (23,000,000 acres per year).
Perhaps this 450,000 kg, a portion of the
1,000,000 kg used in plastics, and the conta-
mination of Lake Ontario is what produced
the residues observed in humans and ani-
mals. That the human residues reported by
Kutz may have resulted from less than part
per billion levels of residue in food was
deduced when extrapolations from animal
studies were made assuming a five-year
exposure. These levels are hundreds of
times less than those in test animals for
which toxicological effects have been ob-
served.
Table 4 lists the positive and negative
aspects of the mirex active ingredient in
ferriamicide. It is Relieved that the hazards
evident from toxicological results are miti-
gated by the low exposure expected for
humans. Ferriamicide helps solve several of
the problems encountered with the use of
mirex, such as biomagnification, persist-
ence, lack of metabolism, and kepone pro-
duction, because it promotes degradation to
compounds whose chemical and physical
properties lessen the problems associated
with these parameters. (For in-depth toxi-
cological information, see Table 5.)
In conclusion, ferriamicide is a much
more cost effective approach to the fire ant
problem than other currently available
methodologies. The effectiveness of this or
other baits is increased by aerial broadcast
application, because the more complete
coverage reduces reinfestation rates.
-------
146
Table 1. Chemical control of IF A.
Table 2. Ferriamicide bait composition and function.
Chemical
mg Al/acre
dieldrin/heptachlor
kepone
mirex 4X
mirex 2X
mirex 10/5
ferriamicide
Amdro
drenches
> 50,000
2-6,000
1,700
850
454
227
4,000
400-30, 000/mound
Substance
corn cob grit
soybean oil
mirex (0.05%)
Kemamine T1902D
ferrous chloride
citric acid
propylene glycol
Use
carrier
attractant
toxicant
degradation enhancer
degradation enhancer
antioxidant
solvent-kepone inhibitor
Table 3. Field degradation of ferriamicide.
Compound
mirex
10H
8H
5,10 A (trans)
5,1 OB (cis)
8,10A(anti)
8,1 OB (syn)
kepone
2,8
3H, 4H, etc.
ppm
0.052
0.006
0.010
0.005
ND
0.037
0.289
0.023
0.069
0.129
Confirmation
yes
yes
yes
yes
yes
yes
no (det.
no (det.
yes
7
0.001)
0.001)
Table 4. Pros and cons of mirex.
Pro
Con
efficacious
low rates
bait—targets toxicant
broadcast application
human exposure low
wildlife—nontoxic
low residues in human food
not genotoxic
adsorbs to clay
biomagnifies
bioaccumulates
no metabolism
degrades slowly
residues in wildlife
chronically toxic
liver damage
possible carcinogen
crosses placental barrier
fetal toxicity
-------
147
I
Ul
LJ
O
Q£
Ul
0.
oH
ois 5,10-OIHYDROMIREX
inmt 5,10-DIHYDROMIREX
Figure 1.
0 2 4 6 8 10 12 14
DAYS FOLLOWING DOSING
Percent of radioactivity remaining in rats following a single oral dose
of C-radiolabeled compound (days 1-6: mean of 12 animals; days 7-14:
mean of 6 animals).
-------
148
Table 5. Toxicology summary of ferriamicide.
oral LDso
dermal LD^Q
eye irritation
skin irritation
skin sensitization
inhalation LC5Q
ACUTE TOXICITY1
rats 312 mg/kg
rabbits > 2000 mg/kg
rabbits data not presently available
rabbits data not presently available
guinea pigs data not presently available
rats data not presently available
SUBCHRONIC TOXICITY
1
28-day dietary study on Sprague-Dawley rat
dose levels (ppm): 0.0
biochemistry:
p450
liver SDH
histopathology:
liver
thyroid
0.5
5.0
50
75
ne
ne
ne
ne
dec
inc
ne
ne
inc
inc
inc
ne
inc
inc
inc
ne
inc
inc
inc
inc
90-day dietary study on Charles River rat
dose levels (ppm): 0
histopathology
20
ne
ne
ne
80
me
320
me
1280
mortality:
male
female
hemoglobin
white blood cells
urinalysis
body weight
liver weight:
male
female
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
ne
inc
ne
ne
inc
dec
ne
ne
dec
inc
inc
inc
inc
dec
inc
ne
dec
inc
*
inc
1
Mirex active ingredient
"no dose response
ne = no effect
inc = increase
dec = decrease
SDH = Sorbitol Dy Hydrogenase
-------
149
Table 5, continued
90-day dietary study on beagle dog
dose levels (ppm): 0 4 20 100
mortality:
male
female
ne
ne
ne
ne
ne
ne
inc
inc
alkali n phosphatasae ne ne ne inc
blood
liver weight ne ne ne inc
spleen weight ne ne ne inc
histopathology ne ne ne ne
CHRONIC TOXICITY1
2-year dietary oncogenicity study on mouse (18 males, 16 females/test group)
dose levels: 10 mg/kg/day (7-28) by gavage; then 26 ppm
mortality: all animals before 18 months
histopathology: significant increase in hepatomas
2-year dietary oncogenicity study on Charles River CD rat (26/test group)
dose levels (ppm): 0 50 100
histopathology: ne inc inc
2-year dietary oncogenicity study on rat (report due approximately six months)
dose levels (ppm) 0 0.5 - 50
3-generation reproduction study on prairie vole
dose levels: varied from 0.1 to 25 ppm
results: difficult to evaluate due to protocol deficiencies
and statistical inaccuracies
-------
150
Table 5, continued
TER ATOGENICITY1
Study on Wistar rat
dose levels (mg/kg/day): 0.0 1.5 3.0 6.0 12.5
toxicity (male) ne ne inc inc inc
deciduoma ne ne ne ne inc
death (female) ne ne ne ne inc
weight (female) ne ne ne ne dec
Study on CD rat
dose level: 10 mg/kg (single or during 4 days)
effect: cataracts in neonates
note: toxicity, not teratogenicity
Study on pregnant CD rat
dose level: dietary 25 ppm
effect: neonatal liver enzyme induction of p-nitroanisole
and aminopyrine demethylase
MUTAGENICITY1
Ames test (salmonella)
mirex negative
8-monohydro (photomirex) negative
10-monohydromirex negative
5,10-dihydromirex negative
2,8-dihydromirex negative
Hepatocyte primary culture on human cell negative
hypoxanthine: guanine phosphoribosyl
transf erase assay
Dominant lethal assay in rats
dose levels (administered 10 days prior to mating):
mg/kg/day 0.0 1.5 3.0 Q.Q6
viable embryos/ ne ne ne ne
pregnancy
deciduomas/ ne ne ne ne
pregnancy
pregnancy/mating ne ne ne dec
^ one death
4 one trial
-------
151
Table 5, continued
WILDLIFE AQUATIC TOXICITY1
Static 96-hour LCsn (vertebrates)
channel catfish > 100 ppm
bluegill sunfish > 100 ppm
rainbow trout > 100 ppm
Dynamic Toxicity
fathead minnow 50-60 ppm, no effect
Reproduction of fathead minnow
dose levels:
ppb
hatching success
spawn production
egg production
0
ne
ne
ne
2
inc
ne
ne
3
inc
ne
ne
7
inc
ne
ne
13
ne
dec
dec
34
ne
dec
dec
mirex accumulation factor: 28,000
elimination rate: 54% at 56 days in mirex-free water
Static 96-hour LCsn (invertebrates)
daphnia > 100 ppm
crayfish 1000-5000 ppm
hydra 4.1 ppm
WILDLIFE AQUATIC TOXICITY5
Static 96-hour LCsn
vertebrates: similar to mirex
invertebrates (daphnia): generally more toxic than mirex
5,10-dihydromirex 0.1 - 3.2 ppm
degradates
-------
Table 5, continued
152
WILDLIFE TOXICITY1
Avian Acute Toxicity—Dietary LCsp (ppm)
ring-necked pheasant 1540
bobwhite quail 2511
Japanese quail > 5000
mallard duck > 5000
Avian Reproduction
bobwhite quail dose levels (ppm) 0 1 20 40
results no effect at any dose level
mallard duck dose levels (ppm) 0 1 10
results ne ne ne
herring gull egg dose levels: doses injected into eggs at natural levels
results no effect on hatchability or chick survival
Japanese quail dosed with radiolabeled 14C-Mirex
excretion 85% by 84 days
CONCLUSION: Mirex poses low risk for effects on avian populations.
6moderate reduction in duckling survival
METABOLISM
SINGLE ORAL DOSE EXCRETION: 14C-RADIOLABELED COMPOUND
Compound
Mirex
8-monohydro
10-monohydro
2,8-dihydro
5,10-dihydro
cis
trans
5,8,10-trihydro
Time (days)
14
28
-
14
14
14
6
% Excreted
Total
32
50
-
19
54
25
32
Urine
0.4
neg
-
0.1
15
4
6
-------
153
Table 5, continued
CHRONIC TOXICFTY7
21-month dietary study of Sprague-Dawley male rat (10 animals/dose group)
dose levels (ppm) 0.0 0.2 1.0 5 25 125
mortality ne ne ne ne ne inc
liver weight ne ne ne inc inc inc
liver SDH ne ne ne ne inc inc
histopathology statistical significance not reported
SUBCHRONIC TOXICITY7
28-day dietary study on Sprague-Dawley male rat, 8-monohydromirex
dose levels (ppm) 0.0 0.5 5.0 50 75
liver weight ne ne inc inc inc
liver SDH ne inc inc inc inc
histopathology
liver ne ne ne inc inc
thyroid ne ne ne ne inc
liver p450 ne ne inc inc inc
90-day dietary study on Sprague-Dawley male rat, 8-monohydromirex
dose levels (ppm) 0.0 0.2 1.0 5 25 125
mortality ne ne ne ne ne inc
liver weight ne ne ne inc inc inc
histological ne inc inc inc inc inc
8-monohydro (purity of test compound questionable)
-------
APPENDIX F
A BRIEF OVERVIEW OF THE REQUIREMENTS FOR PESTICIDE REGISTRATION
D.J. Severn
PANEL IV
The following briefly reviews the
requirements for pesticide registration as
they relate to environmental toxicology, and
summarizes how information submitted
under these requirements, together with
available monitoring, is used to prepare
assessments of exposure of humans and the
environment to pesticides.
REQUIREMENTS FOR REGISTRATION OF
PESTICIDES UNDER THE FEDERAL
RODENTICIDE ACT (FIFRA)
*Registrants must bear the burden of demon-
strating the safety of their products. To do
this they submit testing data to EPA, which
generally includes product chemistry, envi-
ronmental chemistry, toxicology, and eco-
logical effects data.
*EPA's registration guidelines specify the
types of data required to be submitted.
These test requirements are use-pattern de-
pendent? for a broadcast application of a
pesticide formulated as a bait, the following
types of data are generally required:
product chemistry: identity and composition
of the product, physical and chemical pro-
perties, analytical methods
environmental chemistry: degradation, en-
vironmental metabolism, mobility, and over-
all dissipation studies
toxicology: acute oral, dermal, and inhala-
tion studies; teratology and reproduction
studies; long-term feeding studies
'wildlife and aquatic organisms: acute avian
and aquatic organism tests; other tests
depend on results of these.
Once submitted to EPA, the data are
reviewed for scientific quality and utility by
scientists in the Office of Pesticide Pro-
grams (OPP). These reviews are used in
making decisions to grant registration under
various conditions, to require further
studies, or to waive additional requirements.
The registration guidelines allow maximum
flexibility in carrying out the required
studies and are meant to guide the genera-
tion of the particular set of data needed to
make the findings required by FIFRA for
registration.
For pesticides registered in the last few
years, these data are generally available.
Older pesticides, however, often have less
data available; reregistration procedures
underway in OPP will require the missing
154
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155
data to be submitted.
EXPOSURE AND RISK CONSIDERATIONS
FIFRA requires EPA to determine what
pesticides will perform their function with-
out unreasonable risks to man or the envi-
ronment. Thus, an assessment of the likely
risks of pesticide use is made during the
course of approval of registration. This
assessment utilizes the data described
above.
Risk assessments require not only an
understanding of the toxicology of a pesti-
cide but also an evaluation of the extent to
which man and the environment may be
exposed to the pesticide. Information on
environmental transport and fate, generated
according to the guidelines described above,
provides a substantial basis for this evalua-
tion. However, the question of direct or
indirect human and environmental exposure
to a pesticide often arises. Assessment of
human exposure requires detailed informa-
tion about actual use practices, normal
human activities at treated sites, and some
measure of the likelihood of actual transfer
to and absorption of pesticide residues in
humans. In the past, EPA used information
on dermal, inhalation, and dietary exposure
to arrive at estimates of the total exposure
likely to arise from the use of a pesticide.
For pesticides applied for fire ant con-
trol, very little information has been avail-
able to estimate exposure of either applica-
tors or the general public. While methods of
monitoring direct exposure have been devel-
oped and extensively used to measure expo-
sure resulting from other types of pesticide
use (Davis 1981), field measurement of ex-
posure to bait formulations has not been
carried out. The exposure of people living
in areas treated for fire ant control is likely
to be very low, and the routes of exposure
to the bait after application are not clear.
Field studies, perhaps using novel methods
of measurement, are needed to define the
routes and extent of exposure.
Another approach to measuring exposure
involves the monitoring of human urine,
blood, or adipose tissue samples. The pre-
sence of pesticide residues in human tissue
provides direct evidence of exposure,
although it does not define the route of
exposure. EPA has for several years carried
out monitoring surveys for organochlorine
pesticide residues in human adipose tissue
samples. When mirex was first detected in
these samples (Kutz 1974) a more extensive
survey was carried out in eight southern
States in 1975 to 1976 (EPA 1980). A total
of 624 adipose tissue samples were
analyzed; 23% contained detectable levels
of mirex. A distribution of the positive
samples is given in Table 1.
Mirex, a lipid-soluble material, is effi-
ciently bioconcentrated in mammalian tis-
sues. While these results do not identify the
actual pathway of exposure, they do demon-
strate that people were exposed to mirex
from its use as a fire ant control pesticide.
-------
156
Table 1. Distribution of positive samples of mirex in adipose tissue.*
State
Alabama
Florida
Georgia
Louisiana
Mississippi
North Carolina
Texas
South Carolina
TOTAL
Zero
36
129
72
83
73
18
38
34
483
Positive
3
8
19
46
63
0
0
2
141
Total
39
137
91
129
136
18
38
36
624
Percent
7.7
5.8
20.9
35.7
46.3
0.0
0.0
5.6
22.6
* Analyses were electron-capture gas chromatography; approximately 10% of the
positive samples were confirmed by mass spectrometry.
EPA also conducted a nationwide survey
(Savage 1981) of organochlorine pesticide
residues in human breast milk. Mirex was
not detected in any of the 1436 samples
analyzed.
USDA has carried out extensive monitor-
ing surveys for mirex in various components
of the environment. A survey of mirex
residues in meat and milk of cows grazing in
areas treated with mirex found no detect-
able mirex in milk but did detect mirex in
meat.
In summary, FIFRA requires that the
risks of the use of pesticides be balanced
against the benefits of their uses. Suffi-
cient information on the risks and benefits
of pesticide use for fire ant control is
needed to arrive at reasonable decisions
regarding this use. Clearly, the use of
mirex has led to mirex residues in the
human population of treated areas in the
southern United States.
REFERENCES
Davis 1981 (author unable to be contacted
to complete citation).
Kutz, F.W., A.R. Yobs, W.G. Johnson, and
G.B. Wiersma. 1974. Mirex residues in
human adipose tissues. Environ.
Entomol. 3:882-884.
EPA. 1980. Unpublished data from pesti-
cide monitoring.
Savage 1981 (author unable to be contacted
to complete citation).
-------
APPENDIX G
ENVIRONMENTAL TOXICOLOGY OF PESTICIDE APPLICATION PROGRAMS
H.N. Nigg
PANEL IV
Most environmental safety decisions
are of necessity based on small tests, i.e.,
acute toxicity to mammals, birds, and
aquatic organisms; chronic toxicity, espe-
cially mutagenicity, carcinogenicity, tera-
togenicity; metabolism; persistence of
residues; human exposure; and other tests
depending on the chemical. Often, how-
ever, companies fail to investigate what
might be termed the "human side" of
chemical use. For instance, what effect
does attractive packaging have on child-
ren? Does it entice them to test the
product? Also, children around 11 years
old are generally more sensitive to toxi-
cants. Many of the areas infested by fire
ants are also playgrounds, school yards,
football fields, etc. Bait should not be
attractive to children and the persistence
and/or application method should assure
that the potential for exposure to children
is zero. Migrant workers pose special
problems, partly due to their social strata.
They may not speak and/or read English.
Often their understanding of pesticides is
zero. Who takes responsibility for these
people for pesticide exposures? These
kinds of issues concerning pesticide regi-
stration need to be addressed.
When evaluating IF A control programs,
the specifics of each suggested chemical or
program is the only relevant information.
But people may use a program unwisely;
unanswered questions and incomplete data
can lead to unforeseen problems.
The Environmental Protection Agency
should focus on the following three areas
when considering a chemical for registra-
tion:
1. Environmental Toxicology
a) toxicity to aquatic organisms. Of
particular importance are the effects
of insect growth regulator (IGR)
compounds on Crustacea. IGR
compounds also may produce lesions
in the insect hormone system as a
mode of action. Similar effects may
occur in non-target organisms and
should be considered when registering
these compounds.
b) toxicity to avian species. The same
comments for aquatic organisms hold
for avian species. Apart from acute
toxicity, effects on reproduc-
157
-------
158
tion are particularly important.
2. Toxicant/Acre
One consideration must be the amount
of toxicant per acre necessary to con-
trol the fire ant. This may mean that
broadcast treatment of large areas by
air may result in less environmental
contamination than a mound drench.
However, mound drench may be more
practical around lakes and streams.
This consideration should be coordi-
nated with the known toxicology of
each compound.
3. Attractiveness of Baits to Non-target
Organisms
This might be accomplished by (1) test-
ing the attractiveness with mice or rats
and chickens, and (2) observing treated
fields during the experimental use per-
mit stage of registration.
These questions can be answered. Ef-
fective and 'safe' materials can be placed
on the market now and can be developed
for the future. The key is a conscientious
recognition that human health and environ-
mental protection have a high priority in
developing pesticides for fire ant control.
-------
APPENDIX H
MODELS FOR DECISION-MAKING
John Wood
PANEL IV
Any large-scale program for controlling
a pest such as the imported fire ant (IFA)
has variable impacts on diverse elements of
society. The U.S. Department of Agricul-
ture (USDA), Animal Plant Health Inspec-
tion Service (APHIS) program managers
must make decisions about the impacts of
large-scale projects in the context of avail-
able research information, the reality of
social and political pressures, and the man-
dates of legislation. These decisions may be
international, national, regional, or local in
scope.
Problems in evaluating possible impacts,
especially for the long term, often arise
because (1) program needs and environment-
al objectives often conflict, (2) alternative
strategies that may arise from research are
uncertain, and (3) legitimate concerns by
diverse groups may be unknown. Because of
these difficulties, long-range planning that
satisfies program needs while maintaining a
sensitivity to environmental impact is an
extraordinarily complex process.
To assist USDA/APHIS in making deci-
sions on pest programs, several computer
simulation models for regional and interre-
gional evaluations were developed.
Although many models have been developed
that deal with the environmental impact
evaluation of pesticide use, these models
tend to be benefit-cost models, and their
use has been designed mainly for pesticide
regulation rather than program impact eval-
uation. Further, they have not used a
framework within which the adequacy of an
environmental assessment model might be
examined. The necessity of examination is
motivated by the widespread use of models
for predicting environmental consequences
of various program activities and by the
reliance on these model predictions for de-
ciding whether a particular program com-
plies with regulatory perspectives.
The environmental pesticide decision
models developed by APHIS center on a
program's environmental situation based on
all current knowledge and understanding,
both scientific and intuitive. The models
were designed for producing defendable as-
sessments of the environmental effects of a
pesticide program and are part of a compre-
hensive APHIS program consisting of: (1)
feeding studies, (2) local effects of a pesti-
159
-------
160
cide program, and (3) large area effects of a
pesticide program. Toxicological data are
derived from information developed by
registrants, from EPA files, appropriate lit-
erature sources, and agency time/dose/re-
sponse feeding studies. The local effects
model and the large area effects model
consider seven types of impacts: human
exposure, off-site area influence, research
area conflicts, rare biota, wildlife, fish, and
aquatic forms.
The decision-making process is complex
and often must deal with the uncertainties
of environmental situations in addition to
the social and economic outcomes. The
USDA/APHIS computer models improve the
ability of pest control program managers to
make environmental decisions on large-scale
programs.
-------
APPENDIX I
CHEMICALS CURRENTLY UNDER
INVESTIGATION FOR POSSIBLE IF A USE
Panel IV
The following summarizes information presented at the IF A symposium by
various chemical companies on compounds that are registered, pending
registration, or proposed for registration for use on the IF A. The information
includes: (1) chemical name and structure; (2) chemical and physical properties; (3)
metabolic and environmental degradative fate and pathways, persistence, etc.; (4)
toxicity; (5) possible mutagenicity, carcinogenicity, and teratogenicity; (6) use
patterns; and (7) proposed label directions. Such information is essential for
registration by EPA.
The information presented by the chemical companies includes their own data
interpretation; inclusion of these data and interpretations do not imply acceptance
by the USDA or the EPA. The use of these new chemicals depends on (1) EPA
regulation; (2) efficacy as determined by USDA, state, and other agencies; and (3)
the marketplace.
161
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162
PESTICIDE SUMMARY DATA SHEET
A. MOUND DRENCH
Chemical Name;
diazinon: Q,Q-diethyl JL-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate
Empirical Formula;
C12H21N2°3PS
Form;
brownish liquid
Chemical Structure;
Molecular Weight;
304
Odor;
"faint garlic
CH,
N
Trade Names;
Diazinon
Chemical and Physical Properties; .
b.p.: 83-84 C/0.002 mm Hg v.p.: 4.1 x 10 mm Hg at 20 C
solubility;
H20 40 ppm, miscible with benzene, cyclonexane, petroleum ether,
alcohol, ether
Degradative Pathways;
CH
CH
0
tHOP(OC2Hg)
CHgOH CHO COOH
-------
163
Toxicology;
mode of action: irreversible inhibitor of acetylcholinesterase
LD50
Acute: rat, oral 76-108 mg/kg
rat, dermal 1000 mg/kg
mallard duck, oral 3.5 mg/kg
pheasant, oral 4.3 mg/kg
LC50
Acute: blue-gill 48 n, 0.030 ppm
rainbow trout 24 h, 0.39 ppm
Uses;
mound drench
Formulations;
wettable powder, emulsive concentrate, microencapsulated
Dosage;
0.5% in water base
-------
164
PESTICIDE SUMMARY DATA SHEET
A. MOUND DRENCH
Chemical Name;
carbaryl: 1-naphthyl n-methyloarbamate
Empirical Formula;
Form;
tan solid
Chemical Structure;
O
Molecular Weight;
201
Odor:
"nearly odorless
Trade Names;
Sevin, Union Carbide Chemicals
Chemical and Physical Properties;
m.p.: 142 C
solubility;
40 pp
Degradative Pathways;
v.p.*0.005 mm Hg at 26 C
OCNHCH-*
hydrolysis
conjugation
0 CNHCH.
hydrolysis
conjugation
0
0 &NHCH-
hydrolysis
conjugation
-------
165
Toxicology;
acute toxicity:
LD-0, rat, oral: 540-800 mg/kg
LDg|I, rat, dermal: 2000 mg/kg
Uses;
mound drench
Dosage;
1.0-1.5 Ib. AI/100 gal. HO, use 1 gt./6 in. mound diameter
-------
166
PESTICIDE SUMMARY DATA SHEET
A. MOUND DRENCH
Chemical Name;
bendiocarb: 2,2-dimethyl-l,3-benzodioxol-4-ol N.-methylcarbamate
Empirical Formula;
Form;
crystalline solid
Chemical Structure:
Molecular Weight;
NA
Odor;
"very slight
0-C-NH-CH.
II 3
O
Trade Names;
Ficam W, BFC Chemicals, Inc.
Chemical and Physical Properties;
m.p.: 128-130 C
solubility;
25 C
water 0.004%
kerosene 0.03%
trichloroethylene 1.0%
O-xylene 1.0%
chloroform 20.0%
dichloromethane 20.0%
gylcerol formal 30.0%
dimethyl sulfoxide 30.0%
v.p.; 5 x 10~6 mm Hg at 25 C
Hydrolysis: 20 C
pH: 5.0 stable
pH: 7.0 t 1/2 10 days
pH: 9.0 t 1.2 150 min
Uses:
1. control of IFA mounds around home (1% dust or 20% WP)
2. perimeter spray to prevent IFA entry into buildings (Ficam 1% dust, WP,
20% WP)
3. IFA mound drench for recreational areas, golf courses, residential areas (by
PCO or turf specialist) (Ficam WP)
-------
Degradative Pathways;
167
OH
OCNHCH3
Toxicolog
mode of action: direct, rapid reversible inhibitor of acetylcholinesterase
Acute:
rat, oral
rat, dermal
rat, oral
rat, dermal
LD50
40-156 mg/kg tech.
566-800 mg/kg tech.
141-250 mg/kg (76% WP)
1000-2000 mg/kg (76% WP)
Subacute:
rat NOEL (ChE depression) 10 ppm
dog NOEL (ChE depression) 100 ppm
Chronic:
rat NOEL 10 ppm
dog NOEL 20 ppm
Mutagenicity: negative
Teratogenesis: negative (rat, rabbit)
Delayed neurotoxicity: negative (hen)
Reproductive toxicity: negative (rat)
ADI calculated at 0.05 mg/kg/day (LD-J:
mallard duck: 3.1 mg/kg
bobwhite quail: 19 mg/kg
chicken: 137 mg/kg
ADI calculated at 0.05 mg/kg/day (LC-J:
blue gill: 96 h, 1.65 ppm
rainbow trout: 1.55 ppm
daphnia: 48 h, 31.7 ppm
Formulations;
1% dust, 76% WP, 20% WP
Dosage;
2-3 teaspoonful in 2 gal. water for large mounds
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168
PESTICIDE SUMMARY DATA SHEET
A. MOUND DRENCH
Chemical Name;
Acephate: O,Srdimethyl acetylphosphoramidothioate
Empirical Formula; Molecular Weight;
C4H1(JNO3PS 183
Form;
solid
Chemical Structure;
HaC-S\ O O
3 ^ II II
H C-*
P-NH—C —CH3
Trade Names;
Orthene, Chevron Chemical Co.
Chemical and Physical Properties;
m.p.: 82-89 C v.p.: 1.7 x 10"6 mm Hg at 24 C
solubility;
water: 65%
acetone: >10%
alcohol: >10%
aromatics: <5%
Degradative Pathways;
Sv. II H
XPNHCCH3
Toxicolc
mode of action; irreversible inhibitor of acetylcholinesterase
Acute:
rat, oral 866 mg/kg, 945
mouse, oral 351 mg/kg
rabbit, dermal >2000 mg/kg
maUard duck 350 mg/kg
pheasant 140 mg/kg
chicken 852 mg/kg
Acute: LC,.0
blue g111 96 hr., 2050 ppm
rainbow trout 95 hr., 1000 ppm
channel catfish 96 hr., 2030 ppm
Gambusia 95 hr., 6650 ppm
-------
169
Uses;
mound drench
Formulations;
75% soluble powder
1.3 Ib./gal. soluble concentrate
9.4% soluble powder
Dosage;
2 tablespoonful (1 fl. oz.) in 1 gal. water as mound drench
-------
170
PESTICIDE SUMMARY DATA SHEET
A. MOUND DRENCH
Chemical Name;
Chlorpyrifos: O,O-diethyl O(3,5,6-trichloro-2-pyridyl) phosphorothioate
Empirical Formula; Molecular Weight;
C9H11C1 3N03PS 35°'6
Form;
white to tan crystals mild, mercaptan
Chemical Structure;
0-C2H5
Trade Names;
Dursban, Dow Chemical
Chemical and Physical Properties; ,
m.p.: 41.5-43.5 C v.p.: 1.87 x 10 mm Hg at 20 C
solubility; octanol/water partition;
1.2 ppm bioconcentration factor 700 (fish)
Degradative Pathways;
(not available)
Toxicology;
Acute: LD50
rat, oral 118-245 mg/kg (M)
rat, oral 82-135 mg/kg (F)
mouse, oral 102 mg/kg
Chronic:
rat (2-yr feeding): 0.1 mg/kg/day NOEL
ADI:
0.01 mg/kg/day
reproduction:
rat: NOEL 1.0 mg/kg/day (3rd generation)
teratology:
rat: NOEL 1.0 mg/kg/day
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171
Toxicology: (cont.)
neurotoxicity: no effect in chickens
Uses;
1. individual mound treatment for IFA control
2. ant control in potted and balled nursery stock
Formulations;
Dursban 4E
Dosage;
1 fl. oz./4 gal. water
one gallon applied to mound
-------
172
PESTICIDE SUMMARY DATA SHEET
B. BAIT TOXICANT
Chemical Name;
Avermectin B.
Empirical Formula;
C47H43°14
Chemical Structure;
Molecular Weight;
831
H3C'
CH,
Trade Names:
Merck, Sharp & Dohme
Chemical and Physical Properties;
(not available)
Degradative Pathways;
(not available)
Toxicology;
mode of action: gamma-aminobutyric acid antagonist (no effect on cholinergic
nervous systems)
-------
173
Uses;
IFA control (not yet registered)
Dosage:
no label, but 0.0077 g/ha prevented reproductive success in IFA colonies
-------
174
PESTICIDE SUMMARY DATA SHEET
B. BAIT TOXICANT
Chemical Name:
Ferriamicide (mirex)
Empirical Formula;
C10CL12
Form;
white solid
Che mical Structure;
Molecular Weight;
542
Odor;
"odorless
Cl
Cl
Trade Names;
Ferriamicide
Chemical and Physical Properties;
m.p.: 485 C
solubility;
1 ppg; water
1-30%: organic solvents
Degradative Pathways;
degradable bait: dechlorination photochemically and thermally
H
Cl
12
H
•CL
C'
lO
H
H
-------
175
Toxicology;
Acute: LD50
rat, oral 312 mg/kg
rabbit, dermal >2000 mg/kg
90-day Subchronic (rat):
mortality (M): NOEL 320 ppm
mortality (F): NOEL 80 ppm
weight: NOEL 80 ppm
liver wt (M): NOEL 20 ppm
liver wt (F): NOEL 80 ppm
histopathology: NOEL 100 ppm
90-day Subchronic (dog):
mortality (M): NOEL 20 ppm
mortality (F): NOEL 20 ppm
liver wt: NOEL 20 ppm
histopathology: NOEL 100 ppm
teratogenicity:
NOEL 1.5 mg/kg/day
dominant lethal:
negative
acute toxicity:
LC50
bobwhite quail 2511 ppm
mallard duck >5000 ppm
LD50
bluegill >100 ppm
trout >100 ppm
Uses;
broadcast or mound application
Formulations;
0.05% mirex; on corn cob grit with amine and ferrous chloride degradation
enhancers plus anti-oxidant (citric acid)
Dosage;
1 Ib. bait/acre; 0.227 mg Al/acre
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176
PESTICIDE SUMMARY DATA SHEET
B. BAIT TOXICANT
Chemical Name;
N-[l-amino-3-nitro-5-(trifluoromethylphenylJ-2,2,3,3-tetrafluoropropanamide
Empirical Formula;
C10H6FN3°3
Form;
yellow solid
Chemical Structure:
Molecular Weight;
349
Odor;
"Lachrymal
02N
O
NH-C-CF2-CF2H
CF,
Trade Names;
Bant, EL468, Nifluridide, Eli Lilly, Inc.
Chemical and Physical Properties;
m.p.: 145 C
solubility;
<10 ppm; water
soluble organic solvents
hydrolysis pH:
5-T1/0 = 15.5 hr
LI &
1 - T1/2 = 3.5 hr
9 - Tj/2 = 2.0 hr
photolysis (EL919
52 days: deionized water
29 days: natural water
-------
177
Degradative Pathways;
N02
NHC CF
Toxicology;
mouse oral (LD5Q)
mouse S.C. (LD50)
rat oral (LDgQ)
dog oral (LD5Q)
rabbit dermaiUiD.J
Acute toxicity: fish & wildlife:
adult bobwhite (LD5Q)
Suv bobwhite, 5-day dietary (LC-J
Suv bobwhite, 5-day dietary (NOEL)
Suv mallard, 5-day dietary (LC_0)
Daphnia magna, 49 hr static (EC5Q)
Daphnia magna, 49 hr static (NOEL)
blue gill, 96 hr static (LCgo)
blue gill, 96 hr static (NOEL)
rainbow trout, 96 hr static (LC5Q)
rainbow trout, 96 hr static (NOEL)
earthwork, 14 day (LC5fl)
Uses;
broadcast bait for IFA control
Formulations;
0.4-0.75% AI
27.6-27.12% vegetable oil
carrier: 72%
EL468
172
-
57
54
48
30
24
27
24
500
fe.
1C»
(NOEL)
LC50>
(EC50>
(NOEL)
)
LC50>
NOEL)
c^
EL919
22
-
17
12
9
7
9
9 (est)
20
200
EL468
25.22
237 ppm
90 ppm
50 ppm
516 ppb
300
291 ppb
62
708 ppb
300
-
H
EL9I9
92452 (N02NH2)
253
237
198 (IP)
-
292
194
176 (IP)
-
400
-
EL919
4.14
50 ppm
-
16.7 ppm
678 ppb
250
269 ppb
56
528 ppb
330
3.68 ppb
— CF2CF2H
Dosage;
"278 g AI
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178
PESTICIDE SUMMARY DATA SHEET
B. BAIT TOXICANT
Chemical Name;
Tetrahydro-5,5-dimethyl-2-(lH)-pyrimidone [ 3-] [ 4-trifluoromethyl)-phenyl]
-1- [ 2- [ 4-(trifluoromethylphenyl)ethenyl ] -2-propenylidenehydrazone]
Empirical Formula;
C25H24F6N4
Chemical Structure:
Molecular Weight;
494
CH=CH-C-CH=CH
H3C CH3
Trade Names;
AC 217,300, Amdro
Chemical and Physical Properties;
solubility;
octanol/water partition;
206
Toxicology;
mode of action: stomach poison
acute:
rat (oral) LD-,,: 1213 mg/kg
rabbit (dermaT) LD : 5000 mg/kg
subacute:
dog (3-month) (testicular atrophy): 3 mg/kg NOEL
rat (3-month) (testicular atrophy): 50 ppm
reproduction (multigeneration): 50 ppm NOEL (rat)
teratogenicity: negative (rat, rabbit)
-------
Degradative Pathways;
179
COOH
N
I
N
AC 217,300
HN NH
CH3 CH3
(SOIL METABOLISM)
" // \
-~=-
CH - C-CH=CH-V /~CF3
CH=CH
COOH
Uses;
conditional registration for IFA control at 4-6 g/acre AI
Formulations;
0.88% bait formulation
Dosage;
4-6 g/acre
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180'
PESTICIDE SUMMARY DATA SHEET
C. INSECT GROWTH REGULATORS
Chemical Name;
Methoprene: isoprop l-(2E,4E)-ll-methoxy-3,7,ll-trimethyl-2,4-dodecadienoate
Empirical Formula;
C19H34°3
Form;
amber liquid
Sp. gr 09261 at 20 C
Chemical Structure;
Molecular Weight;
3TO
Trade Names;
Altosid, Zoecon Corp., Palo Alto, CA
Chemical and Physical Properties;
v.p.: 2.37 x 10"5 mm Hg at 25 C
solubility;
water: 1.39 ppm
soluble in organic solvents
Degradative Pathways;
HO
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181
Toxicology;
acute:
rat (oral) LD^: >34,600 mg/kg
dog (oral) LIFel: 5000-10,000 mg/kg
chronic:
neither mortality nor deleterious effects at 5000 ppm in rat and 2,500 ppm
in mouse
Uses;
broadcast bait for IF A
Formulations;
1% bait
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182
PESTICIDE SUMMARY DATA SHEET
C. INSECT GROWTH REGULATORS
Chemical Name:
l-(4-isopropylphenyl)-4,8-dimethyl-8-methoxynonane
Empirical Formula;
(
Form:
C20H36°
liquid
Chemical Structure:
H3C-0
Molecular Weight;
NA
Odor:
"odorless
Trade Names;
MV-678, Stauffer Chemical Co.
Chemical and Physical Properties;
b.p.: 192.6 C/10 mm Hg
solubility;
water: 1 ppm 20 C
v.p.: 9.3 x 10 x 10~° mm Hg at 26 C
octanol/water partition;
7.6 x 10"4
hydrolysis:
pH 4.2: 0% 20 days, 6% 31 days
pH 7.0: 0% 20 days, 4% 31 days
pH 9.2: 0% 20 days, 5% 31 days
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183
Degradative Pathways;
HO
Uses;
broadcast bait for IFA
Formulations;
1.2% bait
Dosage;
^178 g Al/acre, spring and fall
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184
PESTICIDE SUMMARY DATA SHEET
C. INSECT GROWTH REGULATORS
Chemical Name;
1- [ (5-chloropent-4-ynyl)-oxy ] -4-phenoxyben zene
Empirical Formula;
C17H15°2CL
Chemical Structure:
Molecular Weight;
286.6
Trade Names;
JH-286, Montedison, USA, New York City
Chemical and Physical Properties;
m.p.: 28-30 C
solubility;
soluble in most organic solvents
Degradative Pathways:
(not available)
Toxicology;
acute rat (oral) LD5Q: >3000 mg/kg
rainbow trout (LC-J 96h:>10 ppm
goldfish (LC5Q) 96h: >20 ppm
guppy (LC5Q) 96 h: >10 ppm
mutagenicity: negative
Uses;
broadcast bait for IF A
Formulations;
1% and 2% baits
Dosage;
11-20 g/ha AI
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185
PESTICIDE SUMMARY DATA SHEET
C. INSECT GROWTH REGULATORS
Chemical Name:
ethyl [ 2-(pfhenoxyphenoxy)-ethyl] carbamate
Empirical Formula;
Form;
solid
Chemical Structure:
Molecular Weight;
NA
Odor;
odorless
Trade Names:
RO 13-5223, MAAG Agrochemicals
Chemical and Physical Properties;
m.p.: 50-53 C
solubility;
water: 6 ppm
acetone: > 24%
diethyl ether: > 26%
dimethylformamide: > 21%
ethyl acetate: > 22%
hexane: 0.8%
isopropanol: > 25%
methanol:> 24%
N-methylpryrolidone: > 20%
toluene: > 23%
hydrolysis: none at pH 4,7,10
Degradative Pathways;
by hydrolysis of OC0HK
fi 3
hydroxylation of phenyl rings
-7
v.p.: 1.3 x 10 Torr 25 C
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186
Toxicology;
acute rat (oral) LD.Q: >16,800 mg/kg
rat dermal (LD,-0):>2000 mg/kg
mouse oral (LD): >8000 mg/kg
bluegill (LC-J 96 hr: 2.9 ppm
rainbow trout (LCgJ 96 hr: 1.6 ppm
carp (LC): 10.2 ppm
5Q
Uses;
broadcast bait for IFA
Formulations;
1% to 2% bait
Dosage;
6-12 g Al/ha
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APPENDIX J
COMMENTS ON FERRIAMICIDE AND THE IF A PROBLEM
Mississippi Department of Agriculture and Commerce
The Mississippi Department of Agricul-
ture and Commerce is fully aware of, and
strongly supports, continued research for
better, more precisely targeted control
methods for the IFA. The Mississippi
Department of Agriculture and Commerce
has spent in excess of two million dollars for
research over the last five years. Mean-
while, in the absence of cost effective con-
trol, the IFA population increase has
become critical in Mississippi and other in-
fested states.
Today in Mississippi there is an urgent
need for a safe, economical, effective
method to control this pest. There are on
file at the Environmental Protection
Agency, in excess of 10,000 letters from
individuals, state officials, business firms,
and others explaining the damage caused by
the IFA and the need for an effective,
economical control. Calls are received
daily demanding and pleading for assistance
in controlling this noxious, destructive pest.
Mounds in hay fields have caused farmers to
purchase bigger and more expensive equip-
ment to cope with this problem during har-
vest. It has also forced the soybean grower
to leave a portion of his crop in the field to
avoid expensive equipment repair and down
time. A survey of thirty-five soybean
growers in Choctaw County, Mississippi,
indicates that a loss of one to three bushels
per acre is caused by IFA mounds. Today
there is nothing to control this pest on
agricultural land.
There are major health related problems
caused by the IFA. Desensitization of a
child or adult after a life-threatening
reaction to the IFA is possible, but not
practical for those other than high risk,
highly sensitized individuals. Also it does
not relieve the parent's concern for their
child when ants are present. The presence
of the ant in large numbers in areas of high
human population is leading to increasing
numbers of sensitized individuals; the very
young and the elderly are particularly vul-
nerable. The multiple stings delivered by
the ants are a serious health problem for
these individuals even if they are not sensi-
tized. What will this problem problem be 10
to 50 years from now? Research indicates
that individuals could become highly sensi-
tive to the venom after being bitten or
stung.
The Mississippi Department of Agricul-
187
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188
ture and Commerce has applied to the Envi-
ronmental Protection Agency for condition-
al use of Ferriamicide. Ferriamicide is a
safe, effective, economical bait for control
of the IF A. This bait can be formulated and
sold to the user for 29 cents per pound in
fifty bags FOB plant.
The rate of degradation of Ferriamicide
provides adequate time for it to be effec-
tive, but the toxicant disappears from the
environment 100 times faster than it did in
the old formulation.
The significant and cogent facts con-
cerning Ferriamicide are as follows: Ferri-
amicide that utilizes the proven IF A toxi-
cant mirex. Under conditions of intended
use, Ferriamicide is safe, economical, and
efficacious. It utilizes 227 mg per acre of
toxicant. In addition to the toxicant, car-
rier, and attractant, Ferriamicide contains a
small amount of amine (approx. 1.7%) and
metal salt, which enhances the degradation
of the toxicant. The half-life of the toxi-
cant in bait, in laboratories, and field
studies is about 30 days. To date, studies
indicate the Ferriamicide is (1) effective
against the IF A, (2) causes the toxicant to
degrade rapidly, (3) has less acute toxicity
to nontarget organisms after toxicant
degradation has occurred, (4) the degrada-
tion products of the toxicants are more
polar; consequently, less likely to move in
the environment and less likely to
biomagnify, and (5) there is evidence that
some of the degradation products are
further metabolized in mammaliam systems.
About 1,000,000 pounds of technical
mirex was used in IF A control programs
during the late sixties and early seventies.
Application rates were typically 1700 mg
per acre. These programs were carefully
monitored for harmful efects on wildlife and
people. None were observed. In contrast,
the negative impact of the ants, particularly
regarding health and death of human beings,
is well documented. With Ferriamicide, we
propose a much more limited application of
baits containing only 227 mg of toxicant per
acre. The maximum rates of utilization of
Ferriamicide, based on the history of the
control programs, would be about 15,000,000
pounds per year. At this rate, which is
probably too high by at least a factor of
two, it would take over 130 years to equal
previous use, with a formulation that
degrades 100 times faster, and with a com-
pound that even at the heavier use patterns
did not cause problems in the real world.
Most of the hazards associated with mirex
are perceived in the artificial environment
of laboratory studies. Residues in wildlife
and humans have been observed, but no
correlation between these residues and any
adverse effect has been made. Further
level of residues in humans points to a very
low exposure from the 1 to 3 million pounds
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189
of technical mirex employed in agricultural
and industrial applications.
Reports have circulated for years that
due to food chain magnification the real
fear of using mirex or its by-products will
be apparent in 10 to 20 years. Mirex has
been used since 1962 on every size block,
and was treated from one to three times.
USDA kept complete records as to the date
treated, the amount of mirex applied per
acre, method of application, etc. Research
studies on the habitat of the millions of
acres treated since the beginning of the
control programs should remove any
ecological and environmental fears of using
mirex or its by-products once and for all.
Because the IF A is a real health and
economic problem to humans, animals, and
the economy, we request that the Environ-
mental Protection Agency review applica-
tions for control of this pest as quickly as
possible and give consideration to the low
risk involved because of the small quantity
employed and low potential exposure. These
risks should then be carefully balanced
against the considerable benefits that could
be achieved.
COMMENTS ON SYMPOSIUM
We would like to make a few points
regarding to subjects that were discussed at
some length during the symposium.
1. Much effort was expended discussing
eradication strategies, heptachlor pro-
grams, and other mistakes of the past.
It is good to review past errors, but we
would hope that it is clearly recognized
that these approaches were adjudged
faults and discarded many years ago by
those managing the IFA
2. We heard many times that the programs
of the past failed to contain or eradicate
the ant. The programs in later years
were not designed to accomplish these
goals. Localized control for localized
relief was the goal, and this end was
effectively achieved. Most insect con-
trol programs are temporary. Why
should any intelligent person assume that
the IFA programs should be other than
temporary unless they are proposing
eradications?
3. There is no doubt that when IFA reinfest
an area where their population has been
depleted that initially a large number of
small colonies will result. It is also clear
that after a few years the population
stabilizes very close to pretreatment
levels. In the meantime, close to a year
of relief has been achieved, and the
resurging mounds are smaller which in
many cases present less problems. We
strongly agree that designing more
specifically targeted baits would be a
major contribution to effective IFA con-
trol.
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9/9/82 Revision
APPENDIX K
FIRE ANT FACT SHEET*
PANEL VI
The following is a summary of the products (pesticides) currently registered
for IF A control, including approved Experimental Use Permits (EUP's) and pending
products presently under review. This fact sheet identifies formulation types.
•»
dosage rates, sites of application, application methods, and related points of
interest for each of the pesticides listed.
•Source: Environmental Protection Agency
190
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191
1. Chemical: Arodro PM-15
Company: American Cyanamid
EPA Reg. No's.: 241-260 and 241-261 (0.88% formulation)
Date Registered: 8/20/80 & 8/17/81, respectively
Description of Application
Site: Pasture and range grass, lawns, turf, and non-agricultural lands
Tolerance: 0.05 ppm (pasture, rangeland grass, and grass hay)
Dosage Rate: 6.0 grams a.i. per acre (5 level tablespoons per individual
mound)
Method: Bait broadcast (ground or air application) and mound to mound
treatment
Retreatment 4 to 5 months after first treatment if necessary
Is use for quarantine program? No
Restriction: No restriction on user group.
Points of Interest
Added control of harvester ants and big-headed ants to existing label.
Increased storage stability of the product up to three months after opening.
2. Chemical: Baygon PM-12
Company: Boyle Midway Inc.
Reg. No.: 475-173 (296 formulation)
Date Registered: 6/10/77
Formulation: 2% Containerized Bait
Description of Application
Site: Around the home (lawns, yards, etc.)
Method of Application: Place ant trap near or on mounds
Is use for quarantine program? No
3. Chemical: Bendiocarb (Ficara W) PM-12
Company: BFC Chemicals Inc.
Reg. No.: 45639-1 (76% WP formulation)
Date of Application: 3-25-81
Date Registered: 8-11-81
Site: Mound drench
Dosage Rate: 0.4 oz./8 gallons water
Method: Sprinkler can
Is use for quarantine program? No
Restriction: For use by pest control operators only
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192
Company: BFC Chemicals, Inc.
Reg. No.: 45639-3 (1% Dust)
Site: Mound (tench
Method: Sprinkler can (slurry treatment)
Is use for quarantine program? No
Restriction: No restriction on user group
4. Chemical: Carbaryl PM-12
Company: Union Carbide Corp.
Special Local Need (SLN) No.: SO780024, SC-780025, SC-780026
Date Issued by States 8/14/78
Description of Application
Site: Lawns, pasture, forage grass
Tolerance: 100 ppm in or on pasture and forage grass
Dosage Rates 1.0-1.5 pounds active ingredient (Ibs. a.i.) per ido gallons of
water. 1 quart of dilution per 6 inches of mound diameter
Method: Mound drench. Repeat if mound activity resumes
Is use for quarantine program? No
Points of Interest
Not renewed by State after 12-31-78
Company: Amchem Products Inc.
SLN No.: SC-790030 (50% WP Formulation)
Date Issued by State: 8/13/79
Description of Application
Site: Lawns
Dosage Rate: Same as above
5. Chemical: CHorpyrifos PM-12
Company: Chevron Co.
Reg. No.: 239-2423 (Amendment) (5.3% EC formulation)
Date of Application: 3/29/79
Date Registered: 6/24/80
Description of Application
Site: Ant mounds
Dosage Rate: 2.5 ounces product per gallon of water
Method: Sprinkler can treatment
to use for quarantine program? No
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193
Company: Dow Chemical Co.
Reg. No.: 464-343,464-360 (22.4% and 40.8% EC formulation, respectively)
Date of Application: 11/5/79
Date Registered: 11/17/80
Description of Application
Site: Potting plants
Dosage Rate: 8 ounces product per 100 gallons of water
Method: Dip and drench treatments
Is use for quarantine program? Yes
Points of Interest
USD A has certified effective control with this product
Company: Dow Chemical Co.
Reg. No.: 464-553 (5% granular formulation)
Date Registered: 12/12/79
Description of Application
Site: Potting media, nursery bench
Dosage Rate: 1.0 Ib. product per cubic yard of potting soil
Methods Mix into potting media granular 5%
Is use for quarantine program? Yes
Points of Interest
USDA has certified effective control with this product
Company: Best Products, Inc.
Reg. No.: 20954-46 (6.7% EC formulation)
Date Registered: 8/25/78
Description of Application
Site: Fire ant mounds
Dosage Rate: 2 ounces product per gallon of water
Methods Sprinkler can treatment
Is use for quarantine program? No
Company: Dow Chemical Co.
Reg. No's.: 464-343, 464-360 (22.4% and 40.8% EC formulation, respectively)
Date of Application: 1/17/80
Date Registered: 1/22/81
Sites Mound drench
Dosage Rates 1 fL oz./2 gallons water
Methods Sprinkler can treatment
Is use for quarantine program? No
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194
Company; Cessco, Inc.
EPA Reg. No.: 6959-67 (1% spray formulation)
Date of Application: 11/12/81
Site: Mounds-homeowner
Method: Pressurized-mound injection tube
IB use for quarantine program? No
Dosage Rate: 1%-dependent upon mound size as to time tube is left in mound
Date Registered: 3/26/82
6. Chemical: Diazinon PM-15
Company: Ciba-Geigy Corp. and others
Reg. No.: 100-456 (25% EC formulation)
Date of Application: 10/31/77
Date Registered: 12/18/79
Description of Application
Site: Lawns and recreation areas
Dosage Rate: 0.016 IDS. a.i. per gallon of water; 1 or more gallon per mound
Method: Mound drench
Restriction: Do not apply to feed/food producing areas
Is use for quarantine program? No
Points of Interest
Claim is only for "aids in control of fire ants." Product directed towards
homeowner market.
Company: Thompson-Hayward Chemical Co. and others
Reg. No.: 148-1130 (48% EC)
Date Registered: 8/11/81
Description of Application
Same .as above
Company: Hi-Yield Chemical Company and others
Reg. no.: 34911-23 Granules (5% and 14%)
Date Registered: 7/2/81
Description of Application
' Site: Lawns and recreation areas
Method: Mound application
Dosage Rate: 0.0125 IDS. a.i./mound
Is use for quarantine program? No
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195
Company: Penwalt Corporation
SLN No.: TX-920015 (23% Flowable Micro-encapsulated)
Date Issued by State: 4/2/82
Description of Application
Site: Lawns and other recreational areas
Dosage Rate: 1 fluid ounce/gallon of water
Method: Mound drench (sprinkler can)
Is use for quarantine program? No
7. Chemical: EL-468 (Bant) PM-15
Company: Eli Lilly & Company
BUP No.: 1471-EUP-73 (0.75% formulation)
Date Renewed: 4/30/82-4/30/83
Description of Application
Site: Non-cropland (restricted rangeland and pastureland*)
Tolerance: NA
Dosage Rate: 3.5-6.0 gm ai/A
Methods Bait broadcast or split application (ground or air application)
Retreatment 4 to 5 months after first treatment if necessary
IB use for quarantine program? No
Restriction: Maximum 70 IDS. a.i. over 4600 acres in Texas, Georgia, Florida,
Alabama, Mississippi, Louisiana, and Arkansas
*Do not allow beef cattle to graze treated fields until disappearance of the
bait is assured.
*Do not slaughter cattle for human consumption which have grazed treated
fields without direct consultation with Elanco personnel.
•Do not allow dairy cows to graze treated fields.
8. Chemical: H8-methoxy-4,8-
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196
Points of Interest
Existing stocks could be used until 9/30/82 under cooperation of USDA, State,
and local government officials.
Company: Same as above
EUP No.: 42634-EUP-2
USDA requested an extension and additional use of MV-678 to be used in
Brazoria (County) Texas.
Date Extended: 4/1/82 to 9/30/83
9. Chemical: Methyl Bromide PM-16
Company: Velsicol Chemical Co.
Keg. No.: 876-257 (99.9% pressurized gas)
Date Issued: 9/17/69
Description of Application
Site: Around home, non-cropland
Dosage Rate: 1 ounce of product per 10 square feet mound area
Method: Soil fumigation
Is use for quarantine program? No
Points of Interest
According to Company this product has not been marketed for EPA control in
the last four years.
10. Chemical: Orthene PM-16
Company: Chevron Chemical Co.
EPA Reg. No.: 239-2436 (15.6% EC formulation)
Date Issued: 1/21/81
Description of Application
Site: Around the home
Dosage Rate: 1/2 fl. oz./l gal. H20
Method: Apply on mound and treat a four (4) foot diameter circle around the
mound with sprinkling can
Treat new mounds as they appear
It use for quarantine program? No
11. Chemical: Pyrethrin I & 0 PM-17
Company: Cessco, Inc.
Reg. No.: 6959-58
Date of Application: 10/18/79
Date Registered: 7/2/80
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197
Description of Application
Site: Pastures, golf courses, woodlots, building lots, feed lots, buildings,
parks, and playgrounds
Dosage Rate: Spray as necessary
Method: (Pressurized spray) spray directly on ants
IB use for quarantine program? No
Restrictions: Not for house-hold use
12. Chemical: 1,1,1-Trichlore thane PM-16
Company: Trichem Industries
8LN No.: TX-780053, MS-800055, LA-800026, LA-800022
Date Issued: 12/11/78
Description of Application
Site: Fire ant mounds
Dosage Rate: 2-4 ounce product per mound
Method: Apply to top center of mound
Is use for quarantine program? No
13. Chemical: MK-936 (Avennectin Bj) PM-15
Company: Merck, Sharp & Dohme
EUP Hoc 618-EUP-10 (0.011% and 0.0055% formulations)
Date of Application: 11/25/81
Date Issued: 5/3/82-5/3/83
Description of Application
Site: Non-cropland
Dosage Rate: 25 mg-50 mg a.i. per acre
Method: Broadcast (ground and air)
Is use for quarantine program? No
Restriction: Maximum 63 grams a.i. over 1680 acres in Alabama, Florida, and
Georgia
Do not graze treated fields.
14. Chemical: Imidan N-dnercaptomethyl) PM-15
phthalimide S-{0,0-diniethyl phoshordithioate)
Company: Zoecon Corp.
EPA Reg. No.: 20954-14-(50% WP in pre measured water soluble packets)
Date Registered: 7/8/82
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198
Description of Application
Sites Residential, institutional, commercial, and recreational areas
Method of Application: Individual mound treatment (drench)
1 packet (3.8 gms a.i./gal. water/mound)
Is use for quarantine program? No
Restrictions: For sale and use only in the state of Texas
15. Chemical: Rotenone
Company: Pennick Corp.
EPA Reg. No.: 432-677
Date Registered: 7/20/82
Description of Application
Site: Gardens, lawns, fields, agricultural land, golf courses, recreational
areas, camp grounds and other similar areas.
Method: Drenching the ant mound
Is use for quarantine program? No
16. Chemical: Heptachlor
Company: Do-It-Yourself-Pest-Controllnc.
EPA Reg. No.: 13283*4 (5% granular formulation)
Date Registered: 10/21/74
Description of Application
Site: Buried telephone cable closures
Method: Place 4 ounces (premeasured packet) into buried telephone cable
closure
Is use for quarantine program? No
Restriction: Packaged for the telephone industry
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199
"Pending1' Registration Actions and EUP's for Fire Ant Control
•1. Chemical: Amdro PM-15
Company: American Cyanamid
EPA Reg. No.: 241-260 (Amendment) (PP-2F2627)
Date of Application: 1/7/82 & 12/1/81
Description of Application
Site: Cropland (including pineapple and sugarcane) for control of IF A,
harvester ants, and big-headed ants
Tolerance: 0.05 ppm for all rac's
Dosage Rate: 6.0 gms/ai/acre for imported fire ants and harvester ants;
10.0 gms/ai/acre for big-headed ants
Method: Bait broadcast (ground and/or air) and mound-to-mound treatment
Limitations: All Food Crops: Do not treat within seven days of harvest.
Pineapple; Do not apply more than two broadcast applications per crop
during any twelve month period.
Sugarcane; Do not apply more than three broadcast applications per crop.
b use for quarantine program? No
Status: Company has submitted outstanding long-term chronic studies.
Approval of cropland usage depends upon our review and acceptance of
these long-term data. Review completion expected by end of June.
2. Chemical: MV-678 (same as 18 under PM-17
registered chemical)
Company: Stauffer Chemical Co.
EUP File Symbol: 476-EUP-RNR
Date of Application: 1/27/82
Description of Application
Site: Crop or non-cropland
Dosage Rate: 4.8 gm/ai/acre
Method: Aerial application
Tolerance: None proposed
Status: EUP rejected 4/1/82 due to the need for temporary tolerances or
exemption from tolerances on rangeland and other crops. Awaiting
company response.
Stauffer Chemical also submitted an application for conditional registration
of MV-678
EPA File Symbol: 476-EER
Date of Application: 1/8/82
Description of Application
Same as for EUP above.
Tolerance: An exemption from tolerance was proposed
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200
Status: Objection letter issued 4/6/82. "BiorationaT status of chemical in
question. Additional data would be needed if chemical is not a biorational.
Company responded to our letter 6/1/82. Our answer to the biorational
classification is under consideration.
3. Chemical; Disodium Octaborate Tetrahydrate PM-16
Company: R Value, Inc.
EUP No.: 44313-EUP-R
Date of Application: 9/11/81
Site: Mounds on unspecified sites
Method: Broadcast application and individual mound treatment
Is use for quarantine program? No
Dosage Rate: 4 Ibs. eui./A (broadcast): 1/4 cup product (mound)
Formulation: 5% bait
Status: Objection letter sent 12/18/81; no response received to date; the
applicant had previously indicated that he may try 24(c) registration. The
application is incomplete; additional information regarding program is
needed.
4. Chemical: Methyl chloroform (1,1,1, Trichloroethane)
EPA File: 40708-R Southwest Trichem Industries, Houston, TX
Date of Application: 5/17/77
Site: Urban/rural (non-agricultural)
Dosage: 2 ounces/ant hill
Method: Pouring of chemical on top of ant hill
Formulation: 94.5%
Status: Objection letter dated 11/27/78 (additional safety and chemistry data
needed). Company indicated on 6/23/82 that they were interested in
pursuing registration and would respond to our objection letter.
5. Chemical: Resmethrin
Company: Cessco
File Symbol: 6959-AR, 6959-LO
Date of Applications 10/21/79
Description of Application
Sites: Buildings, playground, pastures, parks, feed, and woodlots
Dosage Rate: Spray as necessary
Method: (Pressurized spray) spray directly on ants
Is use for quarantine program? No
Restrictions: Not for household use
Status: Preliminary acceptance letters issued 6/28/82.
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200.1
6. Chemical: Lindane PM-15
Company: Woolfolk Chemical Co., Inc.
EPA File: 769-LGE
Date of Application: 6/9/82
Description of Application
Site; Home lawns, parks, cemeteries, and recreational and commercial turf
areas
Dosage Rate: 4 Ibs./lOOO sq. ft./ 160 Ibs./acre (4 Ibs. a.i./acre)
Method: Broadcast ground and individual mound treatment
Is use for quarantine program? No
Status: Under review.
7. Chemical: Methylenebis (thiocyanate) PM-31
Company: Vineland Chemical Company
EPA Reg. No.: 2853-43
Date of Amendment Application: 11/2/81
Formulation: 10% liquid
Description of Application
Sites Non-agricultural land
Method: Individual mound treatment (drench)
Dosage: 2 oz. product/gal, water/35 sq./ft.
Is use for quarantine program? No
Restrictions: Not for homeowner use as labeled
Status: Additional efficacy data required and additional testing requested of
applicant by Fire Ant Laboratory (USDA) Gainesville, Florida.
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APPENDIX L
ERADICATION: AN ASSESSMENT OF CONCEPT AND PRACTICE
Edward H. Smith
PANEL V
It is clear that human population growth,
dwindling resources, and global inflation will
increase the pressure for more effective
pest control. In the case of insect control,
we will need all the options we can get.
Insect resistance to insecticides is a growing
problem. Some of the "third generation"
insecticides have not fulfilled thier earlier
promise, and the gap between concept and
practice is still very wide for some promis-
ing control technology such as pheromones.
In addition, despite a concerted effort to
prevent the introduction of new pests,
present methods cannot offset the growing
global commerce that increases the likeli-
hood of new pest introductions. The time-
lessness of this assessment is heightened by
new technology which opens options that
were previously unavailable. This in turn
raises new questions regarding the philo-
sophical, social and economic issues in-
volved in the concept of eradication. And
within the many facets of the problem lies
the question: Does humankind have the
power to eradicate pests, and if so, does it
have the right to do so?
Eradication, the elimination of a pest
from an environment, has great appeal on
two counts. The first appeals to human-
kind's sense of dominion. In the Judo-
Christian philosophy, humans proclaimed
their dominion over the earth. They were to
"be fruitful and multiply, . . . have domin-
ion over . . . every living thing . .." To kill
and eliminate seems to be a deeply rooted
impulse, whether dealing with a mosquito
taking a blood meal or fire ants established
over thousands of square miles.
The second count, a more rational one, is
rooted in cost/benefit relationships. The
control of annually recurring pests involves
endless effort and expense. The futility of
the annual ritual of boll weevil control with
the full knowledge that one would be no
further ahead the next year offends the
sensibility of rational people dedicated to
education and research. Some of today's
leaders in plant protection have vivid child-
hood memories of long cotton row, sun, rain,
weeds, and insect pests which sentenced
them to endless toil. Through the drudgery
remained the conviction that there had to
be a better way. Despite the tremendous
gains in the science and practice of plant
201
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202
protection, however, the magnitude of pest
losses has not changed greatly over the past
eighty years (Metcalf 1980).
All these things considered, it is not
surprising that the concept of eradication
greatly appeals to the human intellect.
Modern agriculture is essentially the man-
agement of resources, the establishment of
favored plants in ecosystems where they did
not occur naturally, like maize in Africa.
To remove pest species from vast areas
follows as a natural aspiration in the evolu-
tion of agriculture.
SEMANTICS
Professional entomologists differ widely
on the issue of eradication. One of the
contributing factors to the controversy is
the difficulty of aggreeing on what is meant
by the term "eradication." For the purpose
of this discussion, I define eradication as
eliminating an existing pest population from
a specified area. The term "eradication"
has been so misused and has fallen into such
disfavor that one wishes it could be dis-
carded in favor of a term devoid of the
ambiguity and prejudice of the past. As this
semantic option is not readily available, we
can at least qualify our use of the term by
including a specification of the geographic
area involved.
Withoug specifying the area from which
the pest population is to be eliminated,
discussions are meaningless. As the target
area for eradication increases in size, so do
the complexities. While no conceptual and
philosophical issues arise in undertaking the
eradication of a pest from an individual
plant, field, or entire county, many complex
issues arise if the scope is regional, conti-
nental, or global.
The factor of time also deserves con-
sideration. Presumably, eradication, the
elimination of a pest population from a
specified area, would last indefinitely or
until the pst is reintroduced by humans or
gains access by its own migration, clearly
the spatial and temporal dimensions of erad-
ication require attention.
PROFESSIONAL PHILOSOPHY
The primary reason whyentomologists
have not come to consensus on eradication
is that they simply have not addressed the
issue seriously. A review of literature
shows that the issue has been largely ig-
nored. Other factors have contributed to
confusion and ambiguity. As already
pointed out, there is ambiguity regarding
the meaning of the term. Additionally,
many entomologists have direct interest in
the issue. The chief proponents of eradica-
tion have been USDA scientists, and their
leader, Dr. E. F. Knipling, acting as scien-
tist/administrator, has played a key role in
advancing the concept and programs. (Knip-
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203
ling 1979). Lines became drawn between
state and federal workers. Mistakes of
logistics and administration became con-
fused with soundness of concept. Politi-
cians, producers, and environmentalists
gathered in the drama and added their
biases to those of the professionals.
The issue of eradication was featured at
the annual meeting of the Entomological
Society of America in 1977. The title of the
topic was "Eradication of Plant Pests—Pro
and Con" (Bull. Entomol. Soc. Amer., 1978,
24(l):35-53). The format was that of de-
bate; however, as noted by one of the speak-
ers (Rabb), this format was not conducive to
an objective treatment of the topic. To
conclude that two speakers were "for" erad-
ication and two "against" eradication is in-
accurate and an oversimplification. The
"con" speakers, Newsom and Rabb, deplored
the excesses, weak research data base, es-
calating budgets, and decision making pro-
cess in some cases. They offered caution
but they did not take a stand of unequivocal
opposition to area eradication. The "pro"
speakers, Eden and Knipling, acknowledged
some mistakes of eradication programs, but
urged that the potential benefits of the
strategy not be overshadowed by failures of
the past, especially in light of the advancing
technology applicable to eradication pro-
grams. It is unfortunate that the areas of
agreement and directions for the future
were not more effectively identified in the
forum.
The goal of global eradication raises
serious moral and philosophical questions.
While most case histories of eradication
involved objectives much more modest than
global eradication, the issue of global eradi-
cation needs to be addressed by entomolo-
gists. The current range of views is well
illustrated by the statements of two con-
temporary leaders. Newsom (1979) states,
"I do not consider it to be morally wrong and
ecologically disasterous to attempt to eradi-
cate some pest species." By contrast Met-
calf says, "I do firmly believe that species
should be regarded as sacred and man indeed
has no right or reason to destroy them" (as
cited in Perkins, 1982, p. 190).
Perkins (1982) has examined the philo-
sophical foundations of entomology as they
have influenced the development of the
major new pest management concepts: in-
tegrated pest management (IPM) and total
population management (TPM). He proposes
that these paradigms are imbedded in a
matrix of ecological theory with the crucial
differences being in the position accorded
humans. He subsequently applies labels to
the .underlying presuppositions of IPM and
TPM:
"Integrated Pest Management
•Naturalistic'—A belief system that man
is a part of the biosphere but that he cannot
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204
be the total master of it. He may manipu-
late for his own benefit, but there are
intrinsic limits to his manipulative powers
that reside in the properties of the material
world."
"Total Pest Management
•Humanistic'—A belief system that man
is part of the biospere and that he can be
master of it. He may manipulate it for his
benefit, and there are no intrinsic limits to
his manipulative powers that reside in the
properties of the material world. The
limits, such as they are, stem from his
current ignorance of natural processes."
Ironically, until the late 1960's, no econ-
omist devoted serious attention to the prob-
lems of the entomology. More ironic is that
even more recently have the philosophical
foundations of entomology been considered,
despite the burning philosophical question of
our relationships to the natural world and
our right to eradicate living organisms,
termed pests, in a purely anthropocentric
classification. Perkin's work drawing on the
history of science, philosophy, and a schol-
arly brush with entomology and its leaders,
is certain to stimulate consideration by en-
tomologists of animal rights, the issues of
eradication, and related issues of the era of
environment and ecology.
INTRODUCED SPECIES
From earliest colonial time, normal
commerce has resulted in the introduction
of exotic insect species. Sailer (1978) re-
ported that of the 700 important arthropod
pests in the U.S. (contiguous states), 35%
are introduced species and these account for
50% of total insect losses. Although the
threat represented by introduced species
was recognized early, it was not until 1912
that the Plant Quarantine Act was passed,
but only in 1920 was it fully implemented.
Despite concerted efforts by regulatory
agencies, species continue to gain entrance
at an annual rate of approximately nine
species per year (Sailer 1978).
Clearly even with the growing effective-
ness of quarantine programs, introductions
will continue due to the tremendous speed
and volume which characterizes modern
transportation of goods and people. Accord-
ing to Elton (1958): ". . . we are living in a
period of the world's history when the
mingling of thousands of kinds of organisms
from different parts of the world is setting
up terrific dislocations in nature."
Bates has considered the role of people
as agents in the spread of organisms (cited
in Thomas 1956) and stresses that "the in-
troduction of an organism into a new region
. . . purposeful or accidental, is often pos-
sible only because the habitat has been
greatly altered by other human activity."
As we continue to manage natural systems
and commute between continents, the intro-
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205
duction of insect species is certain to in-
crease; therefore two possible strategies
could be exclusion, followed by eradication,
and finally containment through integrated
pest management.
THE CONCEPT OF ERADICATION
The species gaining access to a foreign
shore is faced with a formidable problem. It
must find a niche, compete for it, and
contend with the natural enemies. The
ecological complexity of the process is re-
vealed in part by the high proportion of
failures in attempts at deliberately intro-
ducing species for biological control. The
ecological principles involved in the inter-
action are those inherent in the biotic po-
tential of the species versus environmental
resistance. The growing body of knowledge
of the dynamics and behavior of insect pop-
ulations should provide a sounder base for
decisions on the feasibility of eradication
than has been available.
Eradication seeks to dislodge the species
from its niche by increasing environmental
resistance. Considering the vulnerability of
a species in a new habitat and the numerous
biotic and abiotic factors that can be man-
ipulated, the concept of eradication is eco-
logically sound and appealing. However,
numerous factors influence its complexity:
size of the area infested, length of time the
species has had to adapt to its new habitat,
similarity of new habitat to the species'
natural range, specificity of food require-
ments, influence of biological control agents
on the population dynamics of the species,
technology available for structuring a com-
prehensive control program, availability of
funds and personnel, public support, and
cooperation. These considerations are com-
plex and we have had limited experience in
dealing with them. A systematic approach
to evaluating eradication options is urgently
needed.
MAJOR ERADICATION EFFORTS
The early, predominantly rural, Ameri-
can society was much concerned over insect
pests and took legislative action to address
these and related problems as its agriculture
expanded. The Hatch Act of 1888 estab-
lished agricultural experiment stations, thus
providing an organizational structure for
conducting research on agricultural prob-
lems. Similar organizational effort
occurred at the federal level. Some major
insect problems appeared shortly thereafter:
gypsy moth in Massachusetts (1889), San
Jose scale in California (1893), and boll
weevil in Texas (1894). These major intro-
duced pests provided a rigorous test for the
political structure, the emerging entomolo-
gy profession, and the concept of eradica-
tion. In all three cases eradication was
recognized, by some at least, as the first
line of defense.
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206
Numerous other eradication efforts have
been attempted since then (Table 1). Brown
(1961) analyzed four eradication programs,
gypsy moth, imported fire ant,
Mediterranean fruit fly, and screwworm.
His report is drawn upon for the following
brief summaries. His analysis considered
personnel staffing of the projects, research
data base from which programs were pro-
jected, and adaptability of programs as they
proceeded. He reported striking differences
in the resourcefulness of personnel assigned
to the four programs and the kind and
amount of information on which control
operations were based^ As might be ex-
pected,the programs also differed widely in
effectiveness. Based on this analysis, four
recommendations were proposed (the vali-
dity of which were borne out by later exper-
ience):
1. Adequate research must be the founda-
tion for program development with fre-
quent reevaluation to determine effect
and need.
2. Expand funding for USDA research with
special emphasis on basic studies.
3. Deemphasize mass broadcast of non-
selective insecticides with augmentation
by other methods.
4. Establish a permanent interagency office
to coordinate control activities and eval-
uate environmental impact.
The following are summaries of several er-
adication programs.
Malaria. This program was the first
undertaken on a global scale. The success
with DDT and other residual sprays in the
late 1940's and early 1950's prompted the
idea of eradicating malaria, and, in 1955 the
World Health Organization adopted a resolu-
tion in support of this objective. This action
was taken despite early signs of anopheline
mosquitoes developing resistance to DDT.
Another factor was that financial support
would wane as early successes reduced the
urgency for control. Favorable progress was
made until 1966. According to Yekutiel
(1981): "The outstanding detrimental factor
was inadequate planning and financing . . ."
Additional factors were the increasing
problem of insecticide resistance, unfore-
seen behavioral characteristics of vectors,
and factors of human ecology. In retro-
spect, the malaria eradication program
failed to meet a number of prerequisites and
now seems unduly ambitious in scope and
objective.
Smallpox. In 1959 the World Health
Organization passed a resolution to globally
eradicate smallpox chiefly by intensive vac-
cination campaigns. Little progress was
made in the following seven years. In 1966
an intensive program was undertaken aimed
at eradication within ten years. The objec-
tive was reached in 1977 by a campaign
involving 46 countries on three continents.
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207
In Dec. 1979 a commission reviewed the
evidence and certified the global eradica-
tion of the disease (Yekutiel 1981). The
presumed eradication of this disease in
which vaccination played an important part
bears limited analogy to global insect erad-
ication.
Screw worm. The screwworm program
represents success and failure of the male
sterilization technique. The program was
conducted in 1958-59 in southeastern U.S.,
principally Florida, and involved the release
of laboratory-reared, sterilized males from
light planes at the rate of 40 million per
week. Results were immediate and
dramatic. The screwworm was eradicated
from the southeastern U.S. at a cost of $10
million.
With this success, attention was turned
to a more ambitious project; rolling the
screwworm back from southwestern U.S. to
a defensible line in southern Mexico. While
the program failed in its objective of eradi-
cation, it did dramatically reduce the
screwworm for the period 1962-76 (Newsom
1978). This experience highlights the diffi-
culty in transposing success from an area
where the species was recently established
(southeast) to a larger area contiguous with
overwintering areas (southwest). The exper-
ience also indicated how difficult it is to
estimate costs of such a project. More
recently, the failure of the autocidal
method of control has been explained on the
basis of genetic diversity between reared
and naturally occurring flies resulting in
different reproductive strategies
(Richardson et al. 1982). While the south-
west eradication program failed based on
the objective of eliminating the pest from
the area, it did provide valuable information
on insect nutrition, behavior, and genetics.
Imported Fire Ant. The red imported
fire ant, Solenopsis invicta Buren, became
established in Mobile, Alabama, in 1943 and
gradually spread to ten southeastern states.
Its status as an economic pest has been
debated for years. The original plan pro-
jected in 1957 called for eradication by
spraying border areas, centers of infesta-
tion, and areas from which it was most
likely to spread. The insecticides, hepta-
chlor and dieldrin, were first used, then
replaced by mirex bait. The debate over
environmental effects of mirex was ended
by agreement with EPA that mirex would
not be used after 1978. All of the insecti-
cides for IFA control were found to ad-
versely effect the environment, especially
wildlife. Thus, the eradication effort ended
with the banning of mirex and with the goal
of eradication further away than ever. The
striking features of this case are that eradi-
cation programs based entirely on insecti-
cide treatments proceeded with virtually no
research data base on either effectiveness
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against the target species or non-target
species.
Boll Weevil. The boll weevil is the kind
of "super pest" that evokes thoughts of
eradication. The eradication strategy was
proposed when the pest made its appearance
in Brownville, Texas, in 1894, but no action
was taken and the pest migrated to the
eastern seaboard by 1922. The boll weevil
has been the target of two major eradica-
tion programs: (1) the pilot program ini-
tiated in Mississippi, Alabama, and Louisi-
ana in 1972, and (2) the boll weevil eradica-
tion program initiated in the North Caro-
lina-Virginia area in 1980. The pilot pro-
gram was to demonstrate the feasibility of
an eradication program, and the second pro-
gram was to apply the technology. The
technology in both cases consisted of mul-
tiple control measures including the inten-
sive use of insecticides. The results of the
pilot program were hotly debated based
chiefly on the issue of the source of boll
weevil found within the demonstration area
(Perkins 1980). Were they migrants or did
they arise from infestations within the
demonstration area? Two committees
charged with evaluating the program con-
cluded that eradication had not been demon-
strated (Chiang et al. 1973). The conclusion
by the committee appointed by the National
Academy of Sciences to evaluate the more
extensive eradication program was that the
objective of eradication had not been
reached. The committee recommended that
"the potential for eradication should be per-
iodically reevaluated" and that there should
be "an indefinite postponement of the Opti-
mum Pest Management (OPM) Boll Weevil
Eradication (BWE) programs. . . ." (National
Academy of Sciences 1981). The debate
over the issues continues (Wade 1981). The
Committee supported the eradication con-
cept as being worthy of revaluation, but
discouraged implementation pending further
advances in technology. The committee's
view was undoubtedly influenced by the sig-
nificant advances made in integrated pest
management of cotton pests in recent years
(Adkisson et al. 1982).
Mediterranean Fruit Fly. There have
been two major efforts to eradicate this
pest from Florida and the adjoining area.
The first in 1929 involved ten million acres
representing three-fourths of the bearing
citrus land of Florida. The major features
of the program included destruction of fruit
in the infested area, strict quarantine, and
extensive use of bait spray (brown sugar,
molasses, and lead arsenate or copper car-
bonate). In the short span from April 6,
1929, when infested fruits were discovered
until July 1930, the fruit fly was eradicated.
The strategy for dealing with the 1959
infestation was considerably altered from
that used in 1929. Destruction of fruit was
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209
deemphasized in favor of fumigation. The
crude bait used earlier was replaced by
protein hydrolysate and malathion applied
by air. Eight hundred thousand acres were
sprayed one or more times. In addition,
detection methods were developed using An-
gelica seed which was later replaced by a
synthetic attractant, siglure, containing
esters of cyclohexane carboxylic acid.
Through these combined efforts, the fly was
eradicated in less than two years with no
serious effect on wildlife and relatively
little imposition on the public. A striking
feature of the 1956 experience was the
effectiveness with which the research find-
ings, developed by L. F. Steiner at USDA
station in Hawaii, were applied to this pro-
blem on the continent.
The cases briefly cited in the foregoing
represent both successes and failure. From
this limited cross section of cases, several
conclusions seem evident:
Early Detection. The Mediterranean
fruit fly was on two occasions detected
early and dealt with effectively. We tend to
assume that this is likely to be the case
considering our infrastructure of informed
growers, extension and industry personnel,
and resource specialists in state and federal
agencies, but early detection was not the
case.with the cereal leaf beetle experience.
The cereal leaf beetle was identified in
1962, but had apparently been present for
some time and had reached sufficient num-
bers of 1959 to warrant spray treatment on
the initiative of farmers. This occurred in
Michigan, a state well staffed by plant pro-
tection specialists. The development of
surveillance programs for new pests which
provide effectiveness at reasonable cost
poses a severe problem.
Research Base. Control programs must
be based on research findings. Research,
however, is difficult to provide, especially
when a new pest is discovered and the
element of urgency is often invoked as justi-
fication to proceed without essential infor-
mation. It is likely that far more is lost by
proceeding with weak programs than by de-
laying until essential data are available.
Budgeting for Eradication Programs.
Accurate budgeting is extremely difficult
especially for efforts characterized by so
many imponderables. This is to be expected
and tolerated to a point, but it is important
to distinguish between the factor of the
unknown and the practice of covering mis-
takes by increasing the budget. Skill in
assessing progress and adjusting budgets is
needed together with advances in tech-
nology. Above all, science and technology
must take precedence over public relations
and politics if credibility of the profes-
sionals is to be maintained.
Growing Technology and Experience.
Chemical control has been the prevailing
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strategy for the majority of professional
entomologists. Such strategies required
little imagination and ingenuity, and the
legacy of the low ceiling imposed by their
use is still with us. Each case history in
eradication has added to our knowledge,
despite mistakes that cannot be justified,
but growing experience and technology offer
a brighter outlook for future programs.
PREREQUISITES FOR ERADICATION
Based on experience of the past and
current knowledge of population dynamics,
it should be possible to determine with
better accuracy the probability of success in
eradication efforts. A listing of issues that
should be considered follows:
1. High socioeconomic importance of the
pest. The eradication strategy generally
involves a comprehensive research pro-
gram to develop the needed technology.
This phase is followed by a complex
phase involving extensive control pro-
grams. Such major effort should be
reserved for insect pests of high socio-
economic importance.
2. Specific advantages of eradication over
suppression. Unless there is a clear
advantage to eradication over suppres-
sion, undertaking eradication is not justi-
fied assuming effective technology and
modest costs for suppression programs.
3. Effective monitoring technology. It is
essential that effective technology for
monitoring pest populations be available.
Without such technology it is impossible
to determine the area infested by the
pest or the results of treatment. Recent
advances in pheromone chemistry and
technology offer promise here.
4. Effective control technology. In most
cases, eradication efforts will involve a
combination of measures. The effec-
tiveness of the total effort must be
determined with a high degree of cer-
tainty before undertaking eradication.
This poses special problems because of
the difficulty of interpolating from
small, preliminary tests to large area
tests. The paucity of data on effective-
ness of fire ant treatments was a major
weakness of early eradication efforts.
5. Environmentally acceptable programs.
The impact of control programs on the
environment must be assessed as a pre-
requisite to launching eradication pro-
grams. This poses a difficult problem
because of the time element involved in
making preliminary determinations.
6. Favorable logistical odds. Large-scale
application programs must be basically
simple or the element of human error is
likely to doom the program to failure.
the accuracy of aerial application, or the
thoroughness of scouting for infested
areas are the kind of operations alluded
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211
to here. The likelihood of failure in-
creases as the area increases. Similarly,
the longer the pest has been established,
the better it adapts to its environment.
7. Adequate funding to sustain programs.
In a number of cases, realistic estimates
of costs have not been agreed on before
programs are initiated. Undertaking
programs with open-ended budgets is
likely to place the program in jeopardy
for lack of funding or loss of credibility
due to excessive costs.
8. Adequate administrative resources to
sustain programs. A high level of admin-
istrative competence is required to
insure coordination of the many facets
of an eradication program. This essen-
tial input is more difficult to provide
when programs extend across state and
national boundaries.
9. Favorable socioecological conditions.
The success of eradication programs may
depend on the cooperation and active
participation of residents of the area. It
is essential that a high level of support is
assured and that regulatory authority
can be invoked to take required
measures.
10. Favorable cost benefit relationships.
The great appeal to eradication pro-
grams is that through the initial "capital
investment" phase the pests will be
eliminated, thereby avoiding the recurr-
ing costs of control programs. These
cost/benefit relationships need to be cal-
culated very realistically to avoid disal-
lusionment.
Prerequisites cannot assure successful
eradication programs. An element of risk
will always remain. But by analyzing a
program against the list of prerequisites can
increase a program's success.
CONCLUSION
Controversy has plagued the eradication
concept since its inception. It appears that
the weaknesses in technology, logistics, and
administration inevitably became confused
with basic concept. The result has been
that a strategy which should have great
appeal has been placed in disrepute, and the
stigma has become part of the conventional
wisdom of entomology. The myth of the
unsoundness of eradication is passed on in
the classroom. Objective people would not
defend glaring mistakes of past eradication
programs, neither would they deny that in
some situations eradication offers a high
probability for large gains and that a rigor-
ous analytical process can be applied in
determining which cases offer such promise.
Based on experience to date and future
outlook, the following conclusions are
drawn.
1. The concept of eradicating an insect
pest from an extensive geographical area
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212
is sound biologically, socially, and eco-
nomically.
2. The eradication strategy has been much
maligned because of the errors of past
programs.
3. Global eradication or extinction of an
insect pest species appears to be an
unreasonable objective on technical
grounds at this point in the state of art
and technology.
4. Global eradication poses complex philo-
sophical considerations that should be
addressed. Pending better understanding
of the implications of extermination, it
should not be acceptable on philosophical
grounds.
5. The eradication strategy should be ac-
cepted as a viable option subject to
rigorous assessments to determine its
appropriateness in specific cases.
6. To remove the constraints currently im-
posed on the eradication strategy will
require new alliances of biologists,
economists, philosophers, and politicians.
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Richardson, R. H., J. R. Ellison and W. W.
Averhoff. 1982. Autocidal control of
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screwworms in North America. Science
215(4531):361-9.
Thomas, W. L. ed. 1956. Man's role in
changing the face of the earth. Man as
an agent in the spread of organisms, pp.
788-804. Univ. of Chicago Press, Chi-
cago, IL. 1193 pp., ill.
Wade, N. 1981. Weevil war simmers unre-
solved. Science 213:147-879.
Yekutiel, Perez. 1981. Lessons from the
big eradication campaigns. World Health
Forum 2(4):465-90.
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APPENDIX M
BIOLOGICAL CONTROL: ITS HISTORIC USE VS. PROSPECTIVE VALUE TO
CONTROL THE IMPORTED FIRE ANT
Frank E. Gilstrap
PANEL V
Biological control of pest organisms is
currently receiving a great deal of attention
from the public, agriculture, and govern-
ment. Some of this attention undoubtedly
relates to the frequent notion that biologi-
cal control is simply a matter of getting
some "good" organisms and turning them
loose to provide control of a "bad" organism.
Actually, far more is required for success
than simply releasing or protecting "good"
organisms. But if success is achieved after
the appropriate effort, the payoff is gener-
ally well worth the time, energy, and cost.
Though originally employed only in entomol-
ogy to control insects, biological control
now includes plant pathology and weed sci-
ence, the former using microorganisms as
antagonists to prevent plant disease, and the
latter using insects or plant diseases to
control weedy plants. Neither plant science
nor plant pathology are germane to the
present topic and will not be referred to
further.
Most biological control specialists in
entomology describe biological control as an
ecological process wherein pest individuals
are killed by natural enemies and each pest
death produces one to many new natural
enemies. Biological control occurs only as
the result of human activity; when people
are not actively involved either by protect-
ing or releasing natural enemies, the same
process is called natural control. In prac-
tice, biological control is the study and use
of natural enemies to regulate pest abun-
dance at levels where they cause no signifi-
cant detriment to people. Put very simply,
biological control is two sets of three items.
The first set names the kinds of approaches
used, i.e., conservation, augmentation, and
importation of natural enemies; the second
set names the kinds of organisms used, i.e.,
parasites, predators, and pathogens.
Conservation is the practice of conserv-
ing or protecting natural populations of a
known natural enemy, thus encouraging its
suppressive action on the pest population.
This technique is used for a natural enemy
that does not obtain its potential because of
some adverse condition or missing environ-
mental requisite (e.g., pesticides, lack or
proper habitat, lack of continuity in habi-
tat). The solution is to eliminate the adver-
sity or provide the missing requisite, as is
214
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215
commonly done in insect pest management.
Augmentation of natural enemies seeks to
enhance the effect of an exotic or indige-
nous natural enemy by releasing field-col-
lected or laboratory-reared natural enemies
in places where they are needed. Both
conservation and augmentation assume the
use of a relatively effective natural enemy,
but one that for some reason cannot achieve
its potential. Importation of new exotic
natural enemies is the best first option for
biological control of an exotic pest. This
type of biological control, usually referred
to as classical biological control, consists of
introducing one to several exotic species of
natural enemy for permanent establishment
in the area where the exotic pest is causing
damage. The term "classical" applies
because the historical origins of biological
control are tied to numerous successful im-
portation programs of the past.
Importing natural enemies is conceptual-
ly based on the fact that often an exotic
pest is accidentally established in a new
environment without the controlling effects
of natural enemies from its native home.
Exotic arthropods are only rarely pests in
their aboriginal homes, largely because of
natural enemies that effectively control it.
The biological control program seeks to
identify these natural enemies in the pest's
area of origin, ascertain their beneficial
status, and then import and release them for
establishment. This type of biological con-
trol has obtained a worldwide total of at
least 120 successful programs on 120 differ-
ent pest insects; 42 of these programs have
resulted in complete and permanent control
of the subject pest (Coppel and Mertins
1977). Put another way, each of these 42
programs was so successful that the object
pest no longer causes any significant loss or
damage. The remaining 78 programs have
resulted in less than total control, but clear-
ly contributed towards solving the pest
problem. Examining the record a little
differently, of ca. 2300 species of natural
enemies introduced for control of pests in
ca. 600 different situations (essentially
same pests as before but counting each pest
control success separately), 34% of the
natural enemies became established causing
partial to complete control in 60% of the
situations (Hall et al. 1980). In all success-
ful cases of classical biological control, the
outcome has proven economical and has
invariably been environmentally safe. The
President's Science Advisory Committee
(1965) reported that biological control
returned ca. $30 for each research dollar
invested. This compares to a return of ca.
$4 and $15 for insecticides and insect resis-
tant plants, respectively. These benefits
from successful biological control programs
continue to accrue ad infinitum or until
disrupted. In terms of economical return
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216
and safety, the record of classical biological
control successes is the product of routine
commitment, proper training, and appropri-
ate caution exercised by importing person-
nel, and it is the product of properly strin-
gent importation regulations enforced by
governmental agencies. Classical biological
control has historically not been the first
control tactic considered for dealing with
long established or even new exotic pest
insects. Considering long established pests,
17 of 28 identified major insect and mite
pests in the U.S. are exotic in origin (Van
den Bosch 1975). Some of the more notori-
ous insects and mites of exotic origin
include the codling moth, European corn
borer, cotton bollweevil, pink bollworm,
gypsy moth, Japanese beetle, imported fire
ant, alfalfa weevil, green peach aphid, pea
aphid, greenbug, cabbage maggot, and Euro-
pean red mite (Knipling 1979, Van den Bosch
1975). Some have been the object of biolo-
gical control, but most have not and all
continue to cause serious damage.
BIOLOGICAL CONTROL AND INSECT
PEST MANAGEMENT
Any given crop typically supports several
to many phytophagous arthropods, each of
which could cause severe damage if not
controlled. Those not under natural control
may be further suppressed by use of (1) crop
cultivars that are resistant to pest damage
(= host plant resistance); (2) crop production
practices that avoid or minimize pest dam-
age (= cultural control); (3) release of steri-
lized pests that mate with naturally-occur-
ring pests causing production of non-viable
eggs (= autocidal control); (4) chemicals
(hormones) that disrupt a pest's normal
internal processes such as growth and devel-
opment, or chemicals (pheromones) that
interfere with normal communication
between pest individuals of the same
species; (5) pesticides that kill pests (and
often non-pests) by ingestion, inhalation, or
contact with poisons; and (6) biological con-
trol that kills pests using other living organ-
isms. These tactics are used unilaterally or
in concert depending on the crop, pest
insect complex, and level of understanding
for the crop's ecology. Integrated pest
management (IPM) occurs when several of
these tactics are combined, or when one to
several are used based on a well-founded
economic threshold, or when the purpose of
a control procedure is to optimize yield with
costs of production.
Historically, the crisis of insecticide
resistance provoked the serious study of
biological control as a major component of
IPM. Significantly, this push-pull relation-
ship between insecticide resistance and bio-
logical control is changing. Current
emphasis on biological control is inspired
more by economic and environmental pro-
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217
tection considerations than as a choice of
last resort. Crop production systems that
use biological control almost always use
other tactics. Thus, the concept of IPM is
one whereby one to several tactics are
selectively employed in a mutually compati-
ble framework, are based on an economic
threshold, and/or are used to optimize yield
with costs of production. Biological control
is the cornerstone for such IPM programs,
whether they be for glasshouse crops, row
crops, field crops, or tree crops. In IPM,
effective natural enemies are encouraged,
protected, or increased for certain pests and
other controls are selected for other pests
not amenable to biological control. The
alternate tools are those least disruptive to
important natural enemies needed to control
other phytophagous species.
All three biological control tactics are
employed in some IPM programs. For exam-
ple, citrus pest controls in the Fillmore
district of Ventura County (California) con-
sist of classical biological control of four
once-major pests, augmentative releases for
two pests, and occasional pesticides for
three pests only partially controlled by
natural enemies (DeBach 1974). Other
examples of IPM using biological controls as
the focus include peaches in California and
apples in Washington (Hoyt and Caltagirone
1971), glasshouse crops in Europe (Hussey
and Bravenboer 1971, Markkula 1978), citrus
in Israel (Harpaz and Rosen 1971), and sor-
ghum pests in Texas (Young and Teetes
1977, Teetes et al. 1973, Starks et al.
1972). In each example, effective natural
enemies are either imported and established
for essentially permanent control, released
periodically when normal natural enemy
activity is insufficient for control, or are
conserved when non-biological controls are
needed for pests not controlled by natural
enemies.
The invasion of an introduced pest is
potentially the most disruptive event to
affect a well-researched IPM program.
Introduced pests usually originate in a for-
eign country and are not yet adequately
studied for immediate use of biological con-
trols. Eradication efforts in response to
such invasions often result in serious local
disruptions to extant biological controls
used in IPM, and can hinder progress
towards classical biological control of the
new pest. Three recent programs are excel-
lent examples of such an effect. The pro-
grams are citrus blackfly, Aleurocanthus
woglumi Ashby, on citrus in Texas (Hart et
al. 1978; Hart, personal communication) and
Florida (Selhime et al. 1982), and the Corn-
stock mealybug, Pseudococcus comstocki
Kuwana, on citrus in the San Joaquin Valley
of California (Anonymous 1979, Meyerdirk
et al. 1981). In each, it was clear from the
outset that prospects for complete biologi-
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218
cal control were excellent, based on previ-
ous programs on each pest in other parts of
the U.S. or Mexico. Eradication efforts for
each pest in each area caused localized
outbreaks of other pests previously under
control by natural enemies; made pursuit of
classical biological control very difficult;
and failed in spite of intensive efforts and
considerable expenditure of tax dollars.
Exotic natural enemies for each pest were
eventually established by agencies outside
those involved in the eradication effort.
The natural enemies brought complete bio-
logical control.
The issue is not that eradication was
attempted, but that eradication interfered
with the pursuit of alternative control ef-
forts long after it was clear that eradication
was not possible. Clearly, an ingredient is
missing in present protocol for dealing with
an introduced pest.
The invasion of the pink bollworm on
cotton in the lower deserts of southern
California is an exception to the general
rule that invading pests are usually poorly
.researched. This insect had been well re-
searched in Texas where it was suppressed
primarily by cultural controls (Noble 1969).
However, the key Texas tactics of growing
short season cotton varieties and of early
crop destruction were not well suited to
California conditions. Thus, the pink boll-
worm became a new key pest and required
frequent, large volume insecticide applica-
tions. These pesticides totally disrupted the
biological controls used in the previous IPM
program. Natural enemies suppressing the
cotton leaf perforator, boUworm, cabbage
looper, salt marsh caterpillar, spider mites,
and other pests were killed and these pests
resurged to damaging levels. Not only did
cotton producers adopt non-selective pesti-
cides and use them heavily, but such use
greatly accelerated the development of in-
secticide resistance in the target pink boll-
worm and even in other, non-target pests.
Thus, a previously well-founded IPM pro-
gram has become totally useless until the
new key pest is controlled in a non-disrup-
tive manner (Emerson 1974, Reynolds et al.
1975). The pink bollworm remains a key
pest in spite of considerable research into
classical biological control and other tac-
tics, and the normally non-damaging cotton
leaf perforator has risen to pest status
causing such heavy damage that the future
of cotton production in southern California
deserts is threatened.
The programs on citrus blackfly, Corn-
stock mealybug, and pink bollworm exem-
plify what is likely to occur more frequently
in the future when an introduced arthropod
becomes a serious pest in a new area. The
likely, and generally appropriate, response
will be an area-wide eradication program,
though the issues are occasionally not clear-
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219
cut as revealed by Newsom (1978), Rabb
(1978), Knipling (1978, 1979), and Eden
(1978). However, at the onset of an eradi-
cation effort more funds should be devoted
to developing alternative controls should
eradication fail or falter. This point was
made extremely well by W. L. Brown, Jr.,
who over 20 years ago (Brown 1961)
reviewed four area-wide, mass insect con-
trol programs, one of which was the import-
ed fire ant. Brown was highly critical of the
programs because research was not integral-
ly involved at the onset of each program. In
Brown's own words:
Every mass control campaign should
have an adequate research program
functioning as far ahead as possible
before control operations get under way.
The control work should be guided by the
research and not the reverse, and every
campaign should be re-evaluated
frequently to see if a need for it
continues.
It seems clear that we have made very
little progress towards Brown's suggestion, a
fact that is extremely unfortunate as so
much progress is needed in view of today's
complexities for protection of crops, animal
and human health, and the environment.
PROSPECTS FOR BIOLOGICAL CONTROL
AGAINST IFA
Though the imported fire ants (IFA),
Solenopsis richteri Forel and S. invicta Bur-
en, have been residents of the U.S. for ca.
64 and 39 years (Hung and Vinson 1978),
respectively, biological control of each has
progressed only to very early stages. Some
natural enemies have been identified in the
IFA aboriginal home in South America, but
they have not been studied for their roles or
ecological impact. This must be done
before importations can be seriously consid-
ered. Jouvenaz et al. (1981) recently
reviewed the current knowledge of biologi-
cal control prospects for IFA and pointed
out that disease, parasites, and predators
are scarce and ineffective controls in the
U.S.—an expected conclusion given the con-
tinual problems by IFA. They also pointed
out that preliminary searches for natural
enemies of IFA had been done in South
America. The tone of their review was that
at present, exotic pathogens are almost cer-
tainly the only hope for effective biological
control of IFA. Such conclusions however,
are premature and counterproductive as
adequate field evaluations are not yet avail-
able for any natural enemy of IFA. Accord-
ing to Jouvenaz et al. (1981) most biological
control work has been supported through the
USDA-ARS IFA Research Laboratory at
Gulfport, Mississippi, and has been done by
either personnel at the laboratory or by
SAES personnel at the University of Florida
or Mississippi State University. If the
analysis of the Jouvenaz et al. review is
allowed to stand as the operative statement
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220
for future biological control work, and if
only the extant group working on biological
control of IFA continues without addition of
others who are trained specifically in the
principles of biological control, chances are
quite remote for a successful project on
biological control of IFA.
The IFA invasion and spread in the U.S.
is paralleled in some respects by the inva-
sion of the Argentine ant (described by
Elton 1958). The Argentine ant, like the
IFA, is an extremely intense and successful
competitor. As it invaded new areas, it
caused significant reductions in native ant
populations. Native ants most affected
were those that occupied similar niches.
The crux of the Argentine ant story is that
when the competitive advantage of Argen-
tine ant was reduced, by chemicals or other-
wise, the native ants quickly regained a
temporary competitive position. The same
kind of phenomenon would probably occur
with the IFA in the U.S. if an acceptable
non-chemical and economical device is
developed or imported to reduce IFA com-
petitiveness. The rationale for area-wide
control if IFA could be compared to that
needed for biological control of weeds, as
biological weed control is also based on
reducing the competitive advantage of the
exotic weed (Huffaker 1962).
Parasites
Known parasites of IFA are members of
either fly family, Phoridae, or the wasp
family, Eucharitidae. Species of Euchariti-
dae (Orasema spp.) have been reported at-
tacking IFA in Uruguay and Brazil (Williams
and Whit comb 1973). The ants apparently
are not disturbed by the presence of these
parasites during the parasite developmental
time within the ant nest. At least 14
species of phorid flies belonging to two
genera, Pseudacteon and Apodicrania, have
been reported associated with fire ants in
either Brazil or Argentina (Williams and
Whitcomb 1973). According to Borgmeier
(1963, as cited by Williams and Whitcomb
1973), all species of Pseudacteon attack
ants belonging to Solenopsis, Lasius, Dory-
myrmex, or Crematogaster. In nearly all
species of phorids attacking ants, the para-
sites are attracted to disturbed mounds.
Generally, only worker caste individuals are
parasitized. The larvae, depending on the
parasite species, develop in the head capsule
of the adult ant (in which case the ant's
head falls off at pupation of the parasite) or
in the body of the ant larva. In all cases the
parasitized individual is killed and a new
adult parasite is produced.
According to Jouvenaz et al. (1981) (and
those they consulted), none of these para-
sites offer much potential for suppressing
IFA. However, work initiated by Feener
(1981) should be studied further before
developing any conclusions. Feener's studies
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221
strongly suggest that phorids can cause a
shift in the competitive balance between
ant species. His studies were conducted in
Texas, on Pheidole dentata and a native fire
ant, Solenopsis texana, and showed that
Pheidole was unable to respond naturally in
the presence of the phorids. Thus, it did not
recruit normal numbers of major worker
ants to ward off an invasion by the Solenop-
sis. In the absence of the phorid parasite,
Pheidole dominated most confrontations
with Solenopsis, but in the presence of the
parsite, the outcome was usually reversed.
This reversal of dominance was shown to be
seasonal and dependent on the phenology of
the parasite. Feener concluded that the
notorious imported fire ant . . . appears
free of phorid parasites in the United
States, despite the diverse array of
phorid flies (attacking) this species and
its close relatives in South America.
This freedom may partly explain the high
densities of IFA and its competitive
dominance over the (indigenous) fire ant
in southeastern United States.
Parasites for IFA may be far more im-
portant because they disrupt IFA's competi-
tive advantage rather than simply increasing
IFA mortality.
Predators
Indigenous predators of IFA have been
reported by Bass and Hays (1976), Whitcomb
et al. (1973), O'Neal (1974), and Lucas and
Brockman (1981). Reports of predators of
IFA in South America are essentially only
those of .Silveira-Guido et al. (1972) which
are very general. However, the phenomenon
of predation by other species of ants was
examined in Florida by Nickerson et al.
(1975) who reported that predation could
cause up to 60% mortality in post-nuptial
IFA queens. Silveira-Guido et al. (1972) in
their review of predation in South America,
reported on Solenopsis (= Labauchena) dag-
uerrei Santschi, a socially "parasitic" ant
that takes over nests of IFA in Argentina
and Uruguay. When the invader ants are
present in the IFA nest, the IFA workers
stop tending their own brood and tend those
of the invader. Eventually, the IFA colony
vigor attenuates and the nest becomes
extremely unthrifty. According to Jouvenaz
et al. (1981), these ants have little potential
for biological control, due either to poor
searching ability and/or other factors that
inhibit their ability to find colonies of host
ants. Additional study is warranted to pro-
perly identify causes for low frequencies of
occurrence (ca. 4%), and to identify reasons
previous investigators were unable to suc-
cessfully import these parasitic ants to
other locations.
Pathogens
Diseases of IFA are reported to occur
naturally in the U.S. and in South America
(Lofgren et al. 1975). The indigenous patho-
gens are apparently relatively few and do
not seem to exert any significant control in
field populations. However, disease is
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222
reportedly fairly common in South America
where 20 to 25% of the colonies show pre-
sence of disease organisms. Jouvenaz et al.
(1977, 1980) reported that 22 species in the
IF A species complex have been found
diseased in either Brazil, Paraguay, Uru-
guay, or Argentina. Considerable work has
been done on microsporidan diseases of IF A
in the U.S. (Jouvenaz and Hazard 1978) and
in South America (Allen and Silveira-Guido
1974, Knell et al. 1977); however, none have
yet been reported as field evaluated either
in South America or the U.S.
According to Lofgren et al. (1975), the
findings of Allen and Buren (1974), working
with a microsporidan disease, is the most
promising. Knell et al. (1977) report 50 to
95% of the adult ants in some colonies are
infected with the microsporidan pathogen,
causing a diseased condition resulting in less
vigor and destruction of fat bodies. Jouven-
az et al. (1981) appropriately point out that
debilitating diseases might stress fire ant
sufficiently to allow other indigenous ants
to become more successful in competing
with IF A.
RECOMMENDATIONS
1. Studies should be initiated to quantita-
tively evaluate arthropodial and patho-
genic natural enemies of IF A. These
studies should consist of life table analy-
ses and/or experimental methods (as out-
lined by DeBach and Bartlett 1964) and
be conducted for two to five years in the
IF A aboriginal home.
2. Studies to identify the IFA natural
enemy fauna should be continued in the
IFA distribution area in South America.
3. A laboratory should be established near
the center of origin of IFA in either
Argentina or Brazil. This laboratory
should be staffed by the minimum num-
ber of permanent scientists and be easily
accessible to U.S. scientists on tempor-
ary duty studying some aspect of IFA.
4. The classical biological control program
for IFA should be expanded and should at
very minimum include a biological con-
trol specialist (with formal academic
training in biological control), an insect
pathologist, a specialist in taxonomy of
parasitic Hymenoptera (Chalcidoidea) or
Diptera, a quantitative ecologist, and a
taxonomist of Formicidae.
5. Funding should be generated to support
field studies of natural enemies of IFA in
three or five or more IFA-infested states
in the U.S. These studies should be
oriented to understanding the ecology of
IFA, its competitors, and its natural
enemies. Research locations would
serve as loci for release of exotic
natural enemies when they become
available.
6. A review panel should be established,
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223
consisting of an individual from each
facet of the total IF A program (regula-
tory and each research component) and
the various parts of the public sector
(health, environmental protection, com-
merce, etc.). This panel's role would be
to regularly review progress in the IFA
regulatory, control, and research pro-
grams and to critique each. A public
meeting should follow each such panel
meeting.
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Knell, J. D., and G. E. Allen. 1977. Light
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Knipling, E. F. 1979. Role of insecticides
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Lofgren, C. S., W. A. Banks, and B. M.
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Markkula, M. 1978. Studies and experi-
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Buren and Solenopsis richteri Forel.
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APPENDIX N
IMPACT AND MANAGEMENT OF INTRODUCED PESTS IN AGRICULTURE
Marcos Kogan
PANEL V
When insects and plants coexist in evolu-
tionary time, a process of mutual adaptation
becomes established. This process known as
coevolution results from the accumulation
of several lines of defense in the plant and
the gradual adaptation of a few herbivorous
species to overcome such defenses. In fact
some of these defensive traits become posi-
tive stimuli capable of eliciting the behav-
ioral responses characteristic of an herbiv-
orous insect's relationship to its host plant.
Many of the defensive traits are of a chemi-
cal nature and are known as allomones.
However, many plant chemicals have an
allomonal function against the majority of
the herbivores but a kairomonal (or positive)
function for a few species (Norris and Kogan
1980). These latter species are the co-
evolved ones. Key to this adaptive coevolu-
tionary process is the existence of the her-
bivore and the plant in the same geographic
area over an extended period of time.
In addition to the adaptation of the her-
bivore to the plant, another level of coevo-
lutionary process permits parasitoids and
predators of the herbivores to adapt to the
habitat provided by the plant with its full
complement of defensive morphology and
biochemistry. This is the so-called interac-
tion at the third trophic level (Price et al.
1980).
Current revolutionary theory assumes
that plants have evolved to produce an opti-
mal defense strategy against its associated
fauna. In turn the herbivores evolved to
produce optimal foraging and host selection
strategies. The confluence of these opti-
mization processes is a very dynamic system
of herbivore/plant interactions. The lines of
defense usually presented to the herbivores
by the plant include morphological charac-
ters such as hairiness, thorns and spines,
thickening of epidermal tissues, accumula-
tion of waxy layers, etc. Another line of
defense is represented by secondary meta-
bolites. Most of the allomonal and kairomo-
nal compounds mentioned above are second-
ary metabolites. Under natural conditions
the defensive repertoire of a plant operates
synergistically with the complement of na-
tural enemies that regulates herbivore popu-
lations. Through man's interference in agri-
cultural systems plant natural defenses and
natural enemies are often disturbed and the
consequences are "ecological explosions"
(sensu Elton 1958) of the kind that brought
about the present situation with the import-
ed fire ants in the southeastern U.S. (Lof-
226
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227
gren et al. 1975).
GEOGRAPHIC ISOLATION OF PESTS
AND POTENTIAL HOSTS
When Painter first defined the various
categories of resistance in plants against
insects in 1951, he established the category
of pseudoresistance to encompass those
mechanisms that involve the escape of the
plant in space or in time from a damaging
encounter with a potential pest. This is not,
in fact, a true mechanism of resistance.
Not all plants are exposed to all potential
pests because many simply do not coexist in
the same geographic area. As a conse-
quence of the geographic isolation of pests
and potential hosts one can identify two
factors that often account for the explosive
outbreaks that often result from the immi-
gration of a pest into a new region. First
the pest may find suitable host plants in the
new region. Provided that the feeding nich-
es are not adequately occupied by well
adapted native species, the invader will find
the plant defenseless. The historical case of
the invasion of Europe by the grape Phyllox-
era, Phylloxera vitifoliae, illustrates this
point. This North American pest species
appeared in France in 1861 and rapidly
spread to vineyards in other European and
Mediterranean countries. By 1880 the
French wine industry was on the brink of
collapse. Complete control of the pest was
achieved after French vineyards were re-
constituted using grafts of the susceptible
European grape vine scions on the resistant
North American rootstocks. The European
vine, Vitis vinifera, was extremely suscepti-
ble to the Phylloxera, whereas the American
species of Vitis, such as V. riparia, V. rupes-
tris, and others, are virtually immune to the
pest.
The other more commonly reported
mechanism is the release of the immigrant
pest from the pressure of efficient natural
enemies upon invasion of a new area. There
are many well documented cases of this
phenomenon which remains as the conceptu-
al foundaton of classical biological control.
BREAKING THE GEOGRAPHIC ISOLATION
BETWEEN HOST PLANT AND PESTS
The escape mechanisms reported above
are obviously disrupted when the geographic
isolation between a plant and a potential
pest is eliminated. There are two possible
ways whereby geographic isolation between
hosts and potential pests is overridden. One
is the intentional expansion of crops into
new areas. The second is the inadvertent
introduction or the accidental immigration
of a pest into new regions. Most studies on
the impact of immigrant pests have used the
examples of successful colonization of her-
bivores in new regions. These can be illus-
trated by the many cases of immigrant
pests. Also, the successful biological con-
trol of many weed species illustrates what
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228
can be done if the plant is the migrant
species and the herbivores are then inten-
tionally introduced to control the host. Less
attention, however, has been given to the
consequences of introduction of a crop into
a new region (i.e., soybeans). In either case,
however, the result is an imbalance on the
established plant/herbivore system. If the
host happens to be a crop plant, the eco-
nomic impact can be catastrophic.
OVERALL ASSESSMENT
OF IMMIGRANT PESTS
Sailer (1978) made an interesting study
on the number of immigrant species into the
continental U.S. He took into account the
total number of species by order including
those that were intentionally imported for
biological control of insect pests and weeds.
According to Sailer, of 1,379 species for
which economic importance has been as-
signed, 236 are in the category of important
pests, that is, species that cause economic
losses. Of these, some 80 species are ex-
pected to be serious pests. According to
Glass (1975), of the 35 most important
insect pests in the United States, some 20
are of foreign or exotic origin. Among the
most important agricultural pests of foreign
origin are the European corn borer, the pink
bollworm, the boll weevil, the alfalfa wee-
vil, the southern green stink bug, the green
bug, and the pea aphid. By comparison with
immigrant pests of perennial plants such as
forest or orchard trees, range plants, etc.
one has the impression that annual agricul-
tural crops are less vulnerable to the ravag-
es of immigrant pests. If one compares the
area planted to annual field crops to other
crops and to the impact of immigrant pests
of these crops around the world this impres-
sion may have some foundation. There are
some possible natural restrictive barriers
for the successful colonization of insects
associated with annual field crops. Some of
these barriers have been mentioned by Sail-
er (1978).
1) The absence of adequate host upon
arrival of the immigrant; A tropical pest
arriving in an area where the host is not
grown will have very little chance of surviv-
al, for example, pests of soybeans that may
be on board airplanes arriving from the
Orient and landing in San Francisco (see
below).
2) Inhospitable conditions; A similar
situation as mentioned above would have
happened if the same airplane landed in
Chicago in the middle of the winter. The
crop would not be present and the climatic
conditions would be such that any immigrant
pest would have very little chance for sur-
vival.
3) Predation by general native preda-
tors; The immigrant pest may be welcomed
in the new country by a horde of birds and
other general predators that usually abound
near the possible ports of entry. In this case
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229
the unprotected potential pest would have
very little chance for survival.
4) Inbreeding degeneration: Usually,
under current quarantine regulations,
invaders are those few individuals that
manage to escape the controls. These
individuals, assuming that they will
reproduce, bring a very limited gene pool.
The successive generations resulting from
these few initial colonizers will be intensely
inbred which may have as a consequence an
extreme concentration of semi-lethal or
lethal alleles that will eventually lead the
population to degenerate and dwindle.
With these introductory remarks as a
background I would like now to use three
examples of introduced pests in their impact
on the development of crops and their influ-
ence in the ecological research that lead to
their control. Then I will discuss the oppo-
site situation, that is, when the plant is the
"migrant" and is exposed to a new set of
environmental conditions, including a new
spectrum of potential pests.
CASE HISTORIES-EXAMPLES OF
ACCIDENTAL INVASIONS BY IMMIGRANT
PESTS IN AGRICULTURAL CROPS
Among the numerous examples of pests
of foreign origin, three illustrate the ap-
proaches and the impact that these pests
had, not only on the economy of the crops
that the>> ittacked, but also on the direc-
tions of the research that was stimulated by
the very upsurge of these pests. As we will
see later, a common consequence of the
impact of an immigrant pest is public sup-
port to promote allocation of manpower and
funds to the problems that they create.
These pests are the European corn borer on
corn, the cereal leaf beetle on small grains,
and the imported crucifer beetle, a very
recent invader that causes economic losses
to horseradish.
European Corn Borer
This lepidopterous pest of probable Euro-
pean origin was first detected in the U.S. in
1917 in the neighborhood of Boston, Massa-
chusetts. It is, however, probable that the
pest had been around since the early 1900s,
because after its detection and correct
identification, it was recorded over a rather
large area, indicating that spread had oc-
curred in previous years. There is excellent
documentation about the possible means of
invasion. In the early part of the century
rather large amounts of broomcorn were
imported by New England broom manufac-
turers. Much of this broomcorn was import-
ed from Hungary and Italy where the crop
was known to be commonly infested by the
borer. Since the imported broomcorn was
often stored for many months prior to pro-
cessing, the larvae probably completed de-
velopment within infested broomcorn and
the emerging adult moths escaped and
proceeded to colonize neighboring corn
fields and fields of other host crops.
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230
The European corn borer is a rather
polyphagous species capable of developing
on a very large number of grasses as well as
broadleaf plants. It has some definite pre-
ferences for grasses such as barnyard grass,
corn, sorghum, and millet, but does well also
on many dicot weeds and crop plants. This
rather broad host range certainly enhanced
the chance for survival of the initial colo-
nizers.
The spread of the European corn borer
from the initial focus was rather rapid and
continues. According to Brindley et al.
(1975), each year the borer spreads into a
few more uninfested counties within the
states that are known to be infested.
Detailed biological studies started al-
most immediately with the detection of the
pest. Today the European corn borer is
perhaps one of the best studied insects. Of
great interest to the management of the
pest was the early identification of three
ecotypes: a northern univoltine, and two
multivoltines—central and southern. Table
1 summarizes the chronological expansion of
the research activities on various aspects of
the biology and control of the European corn
borer (based on Chiang 1978).
In summary, after the failure of early
attempts at eradication, the current status
of the European corn borer in much of the
midwestern corn belt is one of a dynamic
equilibrium with fluctuating climatic condi-
tions as well as with biological control
Table 1. European corn borer research
activity in the U.S.
1917, 1st reported by S. C. Vinal near
Boston, Massachusetts.
1917-27, Mass. Ag. Exp. Sta. <5c Bur. of
Entomol. (USDA): Surveys, biology,
economic impact control methods.
1930-50s, Intensification of research at
state exp. stations with geographic
expansion of pest, laboratory founded in
Ankeny, IA; biology, ecology, biocontrol,
host plant resistance, chemical control.
1953-62, Regional cooperative research
project on causes of outbreaks:
Monitoring regional fluctuations;
economic thresholds; effect of
parasitoids & diseases; detection of
regional biological races.
1963-70, Regional cooperation on detection
of biological races.
1973, Regional cooperative project on corn
pest management: all phases including
modeling and forecasting.
agents. The European corn borer is still
considered one of the key pests of corn in
the Midwest, but its impact varies greatly
from year to year. There is continuous
effort to monitor and to understand the
dynamics of these fluctuations and to pre-
dict potential outbreaks. Efforts are contin-
uing to identify sources of resistance. Re-
sistant lines to the first brood of the Euro-
pean corn borer have been identified. Re-
search on mechanisms of resistance to the
first brood led to the identification of
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231
DIMBOA, as a key allomone. This research
is classic in the entomological literature.
Identifying the resistance source to the sec-
ond brood has been more evasive. Screening
of the germplasm is continuing with more
effective methods of mass rearing and arti-
ficial infestation. Inbred B52 with high
levels of resistance to the second brood has
been intensified among some 600 accessions
(Brindley et al. 1975). Thus, although, it is a
cause of concern for corn growers and re-
searchers, the situation of the European
corn borer has stabilized. It is an important
economic factor but by no means is it a
limiting factor in corn production in the
Midwest. Farmers, have learned how to live
with the problem and researchers are learn-
ing better ways of coping with the problem.
Cereal Leaf Beetle
Haynes and Gage (1981) offer a state of
the art review on the cereal leaf beetle
situation in North America.
Since the discovery of the cereal leaf
beetle, OuZema meZanopus, in North Ameri-
ca in the early 1960s, research associated
with this species is a chronology of how
society deals with the introduction of an
exotic pest. The numerous facets of the
programs that were implemented to control
cereal leaf beetle reflect the priority placed
on structural change in the agricultural pro-
duction system. The initial response was
detection, then eradication and contain-
ment, followed by an intensive program of
host plant resistance and ultimately a bio-
logical control effort of questionable suc-
cess. A great deal of activity and research
effort since the early 1960's added much to
the understanding of the cereal leaf beetle
problem, but both the activity and the re-
search appear to have had minimal impact
on the present or final outcome.
The first official record of cereal leaf
beetle occurrence was made in 1962 in Ber-
rien County, Michigan. But, according to
Haynes, damaging populations in the area
were probably present since the latter part
of the 1940fs. Thus, actual invasion preced-
ed detection by more than ten years. Ex-
pansion of the area infested by the cereal
leaf beetle occurred rather rapidly; the cur-
rent range extends from Illinois in the west
to New England states in the east, south
into the northern ranges of Tennessee and
North Carolina, and north to Wisconsin.
Strict quarantine procedures and treatment
of potentially infested bales of hay and
grain were imposed. Later it was discovered
that the cereal leaf beetle overwintered
under the bark scale of Christmas trees.
Certification for the movement of these
trees was required. Eradication efforts cov-
ered a period of about seven years and
included extensive areas in Michigan, Indi-
ana, and Illinois reaching a peak of over 1.6
million acres blanket-sprayed with carbaryl
in 1966. Efforts at eradication were aban-
doned after the spread of the beetle was out
of control and the spray program generated
public opposition due to inconvenience to
city dwellers (there were lawsuits against
the sprays by new car owners for pitted
paint on their vehicles).
With the spread of the pest, intensive
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232
programs were initiated in several other
areas of research including: sterile male
techniques, artificial media for mass pro-
duction of beetles, attractants, and biologi-
cal control.
Much of the biological control was based
on the idea of mass rearing the parasitoid
Anaphes flavipes for release. Since the
beetles were not easily reared, cultures
were maintained on beetles collected in the
field. In addition, these stocks of beetles
provided materials for an intensive host
plant resistance program whereby a large
number of wheat, oat and barley lines were
screened. As a consequence of this program
resistance in wheat was found to be directly
related to thrichome length and density. No
high levels of resistance were detected in
oat and barley lines.
Meanwhile, the biological control pro-
gram was intensified by importing additional
natural enemies of the cereal leaf beetle
from Europe. Also an imaginative program
was started with the establishment of a
parasitoid nursery in the USDA Parasite
Laboratory at Niles, Michigan. This nursery
concept allowed redistribution of the parasi-
toids reared on field-infested populations.
The threat of the cereal leaf beetle to
small grain production in the Midwest stim-
ulated one of the most concentrated and
intensive efforts on researching the life
history and ecology of an insect pest. Per-
haps the most beneficial outcome of this
activity has been the impetus that it provid-
ed to the modeling effort at Michigan State
University. As a result of this effort a
program of early detection and modeling
was initiated and provided a pattern for
other such programs in other states. An on-
line system was developed and a network of
weather stations specifically aimed at pro-
viding current weather information for users
of the system was also implemented.
Through continuous monitoring of the
cereal leaf beetle, it is apparent that popu-
lations have generally declined since 1971.
The causes for this decline seem to be the
result of a combination of factors such as
weather related mortality, mortality due to
introduced parasitoids, genetic changes in
beetle populations, and changes in overwin-
tering habitat (Haynes and Gage 1981).
As was the case with the European corn
borer, the cereal leaf beetle is now a per-
manent feature of the grain production sys-
tem in North America. Specialists predict
that the beetle will remain a sporadic pest
requiring occasional treatments. The pro-
gram also demonstrates that if infestations
are not detected very early, efforts at era-
dication are usually futile. Also, given the
particular pattern of adaptation of the pest
to the agro-ecosystem, an equilibrium is
sooner or later developed. It behooves re-
searchers to strive in the painstaking task of
documenting the mechanisms of adaptation
so that a better understanding is gained as
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233
to the real status of these pests and a
perception is also gained as to policies that
should be adopted to cope with future immi-
grant pests.
Imported Crucifer Weevil
Horseradish is a small but a highly valu-
able crop in southwestern Illinois. In 1977 a
grower detected extensive tunneling of
some of his roots. The causal organism was
the grub-like larvae of a weevil later identi-
fied as the European species Boris lepidii
(Bousernan et al. 1978). An intensive pro-
gram started for the study of the biology,
damage potential and control of the weevil
that became known as the imported crucifer
weevil. Because of the small number of
growers involved in horseradish production
in the area, an almost total survey was
accomplished in a short time. The problem
was well defined and a program for monitor-
ing the infestation was initiated. Despite
the circumscribed area of spread no at-
tempts were made at eradicating the pest,
because the pest had already invaded wild
and other cultivated crucifer species. In-
stead, mechanisms were studied to reduce
the spread and survival of the pest based on
a better understanding of its bionomics.
Treatments of sets that are used for the
vegetative reproduction of the crop were
tested using a range of methods from hot
water to immersion in synthetic pyrethroid
solutions.
The problem, as it happened with the
other pests discussed above, seems to be at
this time reduced to only sporadic infesta-
tions. Methodologies are being developed to
cope with these infestations. The main
lesson from this episode was the ability of
researchers to join forces with growers and
generate financial support from state legis-
lators. This support afforded, in turn, a
concerted effort towards the study of the
problem. Such cooperation between growers
and researchers with official legislative sup-
port has resulted in a better definition of
the problem and improved methods of con-
trol.
EXPANSION OF CROPS INTO NEW AREAS
The other method whereby the geograp-
hic barrier between plants and potential
pests is broken is the expansion of crops into
new regions. A good example is provided by
the soybean. Typically a temperate zone
plant, soybean has been pushed into produc-
tion into more and more tropical regions.
The soybean in the midwestern U.S. is only
sporadically affected by serious insect pest
outbreaks. The crop grows vigorously during
a rather short (100 to 120 day) growing
season; however, when it is planted further
south, in northern Florida for example, out-
breaks of insect pests, in particular the
velvetbean caterpillar, occur almost every
year and require one or several spray appli-
cations per season. The velvetbean cater-
pillar breeds throughout the year in southern
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234
Florida and probably in more tropical areas
of the Caribbean Islands. They migrate
north, reaching northern Florida by the time
soybean is growing. Several generations are
possible during the growing season. The
damage caused by these caterpillars can be
extremely severe. Similar outbreaks have
been observed when soybean was planted
into the subtropical regions of Brazil. Ex-
tensive damage is detected by the same
velvetbean caterpillar and a complex of
other defoliators. It is obvious that the
phenology of the pest and the crop have
been synchronized to a point that the
breaching of a geographic barrier has al-
lowed for a new pest syndrome to develop.
It is certainly impossible in this case to
recommend withholding the expansion of a
crop into a certain region, although there
are compelling economic reasons for such an
action. However, it may be useful, from the
standpoint of a global economic analysis of
a crop, to take into account these potential
risks as a crop is considered for extensive
production in a new area. Quite often such
decisions are left in the hands of individuals
or groups who have little or no concern or
awareness of the potential threats that in-
sect and disease pests may have on the
economic production of a crop.
FORECASTING RISKY INTRODUCTIONS
As a native crop of the northeastern
provinces of China, soybean has been
spreading throughout the world as a major
legume crop. Fortunately, up to this point
no major introductions of serious oriental
pests have been detected in the western
hemisphere. Two of these pests are of
particular concern: (1) pod borers, especial-
ly Leguminivora glycinivorella, and (2) the
soybean colonizing species of aphids, espe-
cially Aphis glycines. These pests can be
extremely serious and could completely up-
set the economic production of this crop.
We have made special efforts to compile the
literature on these pests and to get a first
hand perception of their role in soybean
production in the orient, particularly in Chi-
na, Korea, and Japan. Although these ef-
forts cannot guarantee that we will detect
any invasions early enough to avoid their
propagation, they may allow us to establish
beforehand a control strategy to adopt
should such immigrations take place.
CONCLUDING REMARKS
The impact of immigrant pests in agri-
culture in the U.S. has been noticeable. In
no event, except for perhaps the spread of
the boll weevil and the pink bollworm in
cotton, have immigrant pests changed dras-
tically the economic production of agricul-
tural crops. They have generated an enor-
mous body of information and stimulated
very productive research, such as the mech-
anisms of resistance in corn to the European
corn borer or the modeling of the population
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235
dynamics of the cereal leaf beetle. In most
cases also an equilibrium position has been
established whereby the invading species has
been relegated either to the status of a
sporadic or secondary pest, or its control
became part of a global pest management
program. In general, efforts at eradicating
the pest came too late to be of benefit.
Usually detection of these immigrant pests
occurred ten or more years after the proba-
ble date of actual immigration. At that
point the pest had already spread beyond a
reasonable chance for successful eradica-
tion. Thus, for the most part, the recom-
mendation for the control of immigrant
pests does not differ from that of our most
serious native pests. That is, there is no
substitute for thorough, intensive scientific
research of the population dynamics of the
pest and its life system and the development
of a global pest management strategy. It is
extremely important in the case of very
serious potential pests to gain a better un-
derstanding of the potential adaptability of
these pests prior to their introduction. It
would be important, too, to intensify the
efforts towards developing of a methodology
for the early detection of these pests.
REFERENCES
Houseman, J.K., D. Sherrod, C. Eastman,
W.H. Luckmann, R. Randell, and C.
White. 1978. Note on the establishment
in Illinois of Ban's tepidii, a destructive
European weevil. Bull. Entomol. Soc.
Amer. 24:407-408.
Brindley, T.A., A.N. Sparks, W.B. Showers,
and W.D. Guthrie. 1975. Recent advan-
ces on the European corn borer in North
America. Ann. Rev. Entomol. 20:221-
239.
Chiang, H.C. 1978. Pest management in
corn. Ann. Rev. Entomol. 23:101-123.
Elton, C.S. 1958. The Ecology of Invasions
by Animals and Plants. Methuen <5c Co.,
London. 181 p.
Everett, T.R., H.C. Chiang, and E.T. Hibbs.
1958. Some factors influencing popula-
tions of the European corn borer Py-
rausta nubilalis (Hbn.) in the North Cen-
tral States. Univ. of Minnesota Ag. Exp.
Sta. Tech. Bull. N.C. Reg. Pub. 87. 83 p.
Lofgren, C.S., W.A. Banks, and B.M.
Glancey. 1975. Biology and control of
imported fire ants. Ann. Rev. Entomol.
20:1-30.
Glass, E.H. (ed.) 1975. Integrated pest
management: Rationale, potential,
needs and implementation. Entomol.
Soc. Amer. Special Pub. 75-2. 141 p.
Haynes, D.L. and S.H. Gage. 1981. The
cereal leaf beetle in North America.
Ann. Rev. Entomol. 26:259-287.
Huber, L.L., C.R. Neiswander, and R.M
Salter. 1928. The European corn borer
and its environment. Ohio Ag. Exp. Sta.
Bull. 429, Wooster. 196 p.
Kogan, M. 1981. Dynamics of insect adap-
tations to soybean: impact of integrated
pest management. Environ. Entomol.
10:363-371.
Norris, D.M. and M. Kogan. 1980. Bio-
chemical and morphological bases of re-
sistance, pp. 23-61 In F.G. Maxwell and
P.R. Jennings (eds.), Breeding Plants
-------
236
Resistant to Insects. John Wiley & Sons,
New York. 683 p.
Painter, R.H. 1951. Insect Resistance in
Crop Plants. The Macmillan Co., New
York. 520 p.
Price, P.W., C.E. Bouton, P. Gross, B.A.
McPherson, J.N. Thompson, and A.E.
Weiss. 1980. Interactions among three
trophic levels: Influence of plants on
interactions between insect herbivores
and natural enemies. Ann. Rev. Ecol.
Syst. 11:41-65.
Sailer, R.I. 1978. Our immigrant insect
fauna. Bull. Entomol. Soc. Amer. 24:3-
11.
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APPENDIX O
SOME CONSIDERATIONS FOR THE ERADICATION AND MANAGEMENT
OF INTRODUCED INSECT PESTS IN URBAN ENVIRONMENTS
Gordon W. Frankie1
Raymond Gill*
Carlton S. Koehler
Donald Dilly2
Jan O. Washburn'
Philip Hamman3
PANEL V
INTRODUCTION
Plant pests that are exotic to all or parts
of the U.S. are continually being intercepted
at the many ports of entry around the
nation. For example, during the period of 1
October 1978 through 30 September 1979,
the Animal and Plant Health Inspection
Service of the USDA intercepted 18,644
plant pests; 14,002 were insects (APHIS
1981). The number of interceptions has
increased slightly each year, (APHIS 1979,
1980), which can be attributed mainly to
large numbers of travelers using the airways
to commute between countries (G. Snider,
APHIS USDA, pers. comm.). These inter-
national movements will always represent a
potential for the introduction of pest organ-
isms.
This paper will briefly consider some
biological, social, economic, and political
consequences associated with the introduc-
tion of pests (primarily insects) into urban
environments. Although emphasis is placed
on the California experience, the general
trends probably apply to most urban areas
throughout the U.S.
.Entomology, University of California, Berkeley, CA 94720
2Entomology, California Dept. of Food and Agriculture, Sacramento, CA 95814
Q
Entomology, Texas A&M University, College Station, TX 77843
237
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238
CALIFORNIA AS A CASE STUDY
During the past century, numerous intro-
ductions and establishments of insects and
other pests have occurred throughout Cali-
fornia. No exact figures have been tabu-
lated for all taxonomic groups; however,
some idea of the frequency and character-
istics of introductions and establishments
can be gained by examining records of
selected Homopteran families (Table 1).
Compared with other insect groups, the
introduction frequencies are high and are
due to such factors as: 1) many Homop-
terans are relatively sessile and remain at-
tached to their host plants during transpor-
tation; this feature contrasts with members
of other groups that have easily dislodged
life stages; 2) because of their small size,
life stages of many Homoptera are often
difficult to detect; and 3) high volumes of
plant materials (nursery stock and personal
house/yard plants) are continually moved
across state boundaries. When detected
early and when infestations are small in
o
size, it has been possible to eradicate some
of the introduced homopterans, especially
the armored scales. However, a few intro-
ductions have disappeared without interven-
tion by humans (see Table 2 for more speci-
fic information on the homopterans).
Of great interest and concern is the fact
that most introduced horn opt eran species
(85%) were first reported in urban centers
(Tables 1 and 2). This is an important
pattern that undoubtedly applies to pest
species in other toxonomic groups as well.
Points of air and sea entry into the U.S. are
always located in or near significant popula-
tion centers. Further, when people move
among states they generally do so from one
urban center to another. It follows, there-
fore, that urban centers going to remain the
point of first discovery of most exotic pests,
some of which have potentially serious con-
sequences to agriculture and forestry. For
example, the Mediterranean fruitfly, Cera-
titis capitata (Wiedemann), appeared in the
heavily populated San Francisco Bay Area in
1980. In addition, the gypsy moth, Lyman-
tria dispar (L.), although, hardly an exotic
pest new to the U.S., was first discovered
established in California in San Jose in 1976,
and again in 1982 in Santa Barbara—both
urban centers (Hoy 1982). To the north,
gypsy moth activity is concentrated in the
Seattle area of Washington, Salem, and
Portland Oregon, and Vancouver, B.C.—all
urban regions. Examples of other economi-
cally important pests, their first discovery
sites, and their subsequent eradications are
presented in Table 3. As with the Homop-
tera, most of these species were first dis-
covered in urban areas.
Past experience with introduced pests
indicates that species of agricultural, for-
est, or public health importance have re-
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239
ceived top priority for eradication and/or
subsequent intensive management efforts
(for example, Medfly, Japanese beetle, and
gypsy moth). The vigor of these efforts,
some of which require considerable expendi-
tures of resources, directly relates to ad-
verse impacts (economic or health) expected
in the event of widespread establishment.
However, species more appropriately char-
acterized as causing aesthetic or nuisance
damage, which is typical of urban pests such
as most ant aphid species that pose little
immediate economic or health threat (see
also NAS 1980, Levenson and Frankie 1981),
receive considerably less attention as tar-
gets for eradication and/or subsequent man-
agement. In addition, many pests that are
introduced into urban environments are as-
sociated with indoor as well as garden or
yard situations—difficult habitats for eradi-
cation efforts. Further, if surveys reveal
that these aesthetic/nuisance pests range
beyond one square mile (see footnote 2), the
California Department of Food and Agricul-
ture (CDFA) considers them unlikely candi-
dates for total eradication. Quarantines
are, however, imposed to keep these in-
festations localized. Finally, other con-
straints may seriously limit the kinds of
actions taken against introduced aesthetic/-
nuisance pests. It follows, in theory, that
we should expect a proportionally greater
accumulation of pest species in urban versus
agricultural or forest environments, of com-
parable size. For example, the number of
new insect pest species established on the
largest and most important agricultural
crops in northern California over the past
100 years compared to the number of new
established species in the largest cities of
the same region, should show the totals to
be greater in the urban environment, as a
whole. Surveying to test this hypothesis
would require considerable effort which was
not possible given the short time frame for
paper preparation; however, the following
case histories exemplify the relative ease by
which some pests become established in
urban environments.
Iceplant Scales Along California Freeways
From June 1971 to June 1973, two scale
species, Pulvinaria mesembryanthemi
(Vallot) and P. delottoi Gill, were found to
be established in Napa County (north end of
the San Francisco Bay). An initial, unsuc-
cessful, effort was made in 1971 to eradi-
cate P. mesembryanthemi from one small
suburban locality. During the spring of
1973, this scale was found in three cities in
nearby Alameda County. The CDFA con-
cluded that (1) the area infested exceeded
100 acres in three cities in Alameda County;
(2) the scale was probably not "a truly
destructive pest" (agricultural); and (3)
there were several obstacles to eradication,
which included the difficulty of dealing with
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240
hundreds of private residences. As a result,
the CDFA did not implement an eradication
program.
By 1974, iceplant scales were detected
in three San Francisco Bay Area counties
where they were causing extensive iceplant
mortality in private and public landscape
areas. Thus, this urban "nuisance pest"
became a potentially serious economic prob-
lem since iceplants are extensively used as
landscape ground cover in urban areas and
for dune stabilization in coastal areas. Be-
tween 1974 and 1976, the California Depart-
ment of Transportation (CALTRANS), which
maintains the largest acreage of iceplant in
this state (6,000 acres along freeways), be-
came increasingly alarmed as the potential
impact of the scale was realized. In 1976,
at the request of CALTRANS, Cooperative
Extension conducted a pilot study on the
efficacy of chemical control. This study
revealed that some compounds would reduce
scale populations. However, this finding pro-
vided only a partial answer for the manage-
ment of the pest since much remained to be
learned about the scales' biology, behavior,
and ecology, and how this information could
be related to more effective chemical and
other control methods.
CALTRANS and CDFA personnel met
with University of California researchers at
Berkeley in 1978 and resolved to develop a
research program aimed at designing and
implementing an integrated management
program that would effectively deal with
the iceplant scale problem. Two coordi-
nated projects were initiated and funded by
CALTRANS: one aimed at discovering and
establishing natural enemies and the second
aimed at elucidating the scale biology, in-
teractions with host plants, and cultural
practices that might lessen scale damage.
During this same year, foreign exploration
to South Africa, the suspected geographic
origin of iceplant scales, was conducted.
Seven species of natural enemies (parasites
and predators) were discovered and im-
ported to California (U.C. Berkeley) for
rearing and later release. Several of the
parasitoid species are now known to be
established in a variety of the climatic
zones where the scales are found. These
introductions, in addition to natural enemies
already present (six species of parasites and
predators), appear to be providing good con-
trol of the iceplant scales, which have now
spread (primarily by wind) to 17 counties,
including areas of the Central Valley and
Southern California.
Iceplants were initially chosen as a land-
scape ground cover in California because of
their ability to grow in poor soils, tolerance
of high temperatures and salt spray, and low
water requirements. Prior to the introduc-
tion of the scales, iceplants enjoyed a nearly
pest-free existence, and most landscaped
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241
areas appeared healthy and vigorous. The
plant mortality that did occur was attri-
buted to poor soil and nutrient stress. This
suggested that while iceplants appeared to
be healthy, they were actually growing
under suboptimal conditions (J. MacDonald,
personal communication). In the presence
of scales, iceplant landscapes were sub-
jected to an additional stress that created
widespread plant mortality. While biologi-
cal contol was effective, considerable time
was required to colonize and multiply the
natural enemies. This time frame often
exceeded the tolerance limits of the plants.
Laboratory tests indicated that improving
soil conditions through fertilization and
watering lessened scale damage and im-
proved iceplant vigor and health. By im-
proving the fertilizer regimes of freeway
landscapes, it is now possible to maintain
landscape quality where scales are present
until the natural enemies can control the
pest.
The control approach for the scale is an
integrated system emphasizing biological
control. Presently, a system is being de-
signed that will transfer these research
findings to CALTRANS personnel.
Cockroaches in Urban California
The CDF A has recorded the introduction
and establishment of nine cockroach species
in urban California environments; all of the
following species originated from areas out-
side North America:
Species Common name
Blatta latoralis (Walker) Turkistan
cockroach
B. orientalis L. Oriental
cockroach
('black beetle')
Blattella germanica (L.) German
cockroach
B. vaga Hebard Field cockroach
PeripZaneta americana (L.) American
cockroach
P. oustralasiae (F.) Australian
cockroach
P. brunneo Burmeister Brown
cockroach
P. fuliginosa (Serville) Smoky-brown
cockroach
Supella longipalpa (F.) Brown-banded
cockroach
In general, very little effort has been made
to eradicate any of these species.
Two of the most recent California intro-
ductions, PeripZaneta fuligionosa and BZatta
ZateraZis exemplify how new roach species
may become established in California. Peri-
pZaneta fuligionosa was first discovered in
1970 at Sutter Creek. Since that time it has
spread or has been newly introduced from
outside the state to several northern Cali-
fornia counties and at least two southern
California counties. Despite what may be
characterized as spotty initial infestations
of this species over a 12-year period, no
concerted effort was made to eradicate any
of the infestations (Dilly, pers. observ.).
B. ZateraZis was first discovered in 1978 at
the Sharp Army Depot near Stockton. At
that time, army entomologists determined
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242
that the infestation was well established and
widespread (however, it was less than one
square mile: K. Hansgen, pers. comm.) at
the base and had been there for at least two
or more years. The entomologists also con-
cluded that the infestation could not be
eradicated. Officials of the state of Cali-
fornia (see next paragraph) concurred with
this assessment (K. Hansgen), and as a result
the army opted to institute a chemical con-
trol program to manage the population tat a
low level. As of this writing, the roach
remains confined to Sharp Army Depot;
however, a very real potential still exists
for range expansion of B. lateralis in Cali-
fornia from this one small focus.
In summary, cockroaches are not viewed
as agricultural pests and therefore do not
receive top priority as candidates for eradi-
cation by the CDFA. Responsibility for
these pests has been largely assumed by the
California Department of Health Sciences;
however, due to limited budgets and com-
peting (and more serious) public health
pests, cockroaches also seem to receive a
relatively low priority by that agency. In
effect, cockroaches are treated as pests
that cause "only" aesthetic or nuisance dam-
age. One may conclude therefore that a
relatively lax attitude towards cockroaches
has greatly contributed to their successful
2
establishment and spread in California.
BIOLOGICAL IMPACTS
The urban environment abounds with un-
exploited resources that include a vast array
of native and exotic plant species and vari-
ous structures that humans erect (see
Frankie and Ehler 1978). In addition to
physical resources, people may be viewed as
a resource since they often play an impor-
tant role in the ecology of urban pests. For
example, in the case of newly introduced
pests, people may (1) subsequently spread
them to adjacent areas after initial estab-
lishment, (2) take direct action against
them, or (3) fail to take appropriate action
against the pests when they are relatively
vulnerable because of socioeconomic and/or
political constraints (Frankie and Ehler
1978, Nelson 1978, and Frankie et al. 1982).
New pest species usually arrive without
their natural enemies. Although this attri-
bute is recognized for agricultural and for-
est environments, it has been seldom real-
ized in urban environments. For example, a
vast array of natural enemies are associated
with the cockroach species in their native
habitat (Roth and Willis 1960). However,
virtually no effort has been made to seek
out these enemies to set up biological con-
trol programs in the countries where the
cockroach species have been long estab-
lished. A few examples of classic biocontrol
have been attempted against introduced
pests in urban areas, primarily plant pests,
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243
and these are summarized in a National
Academy Report on urban pest management
(pp. 148-153, I960).4 The potential for clas-
sic biological control has been emphasized
by in a paper by Olkowski et al. (1978) when
they used biological control against herbi-
vores on urban shade trees. Although, the-
oretical classic biological control offers
an attractive means for dealing with some
introduced urban pests, success is by no
means a certainty (consider the gypsy moth
program).
As noted earlier, introductions and es-
tablishments of pest organisms in urban Cal-
ifornia environments have occurred contin-
uously for many years. Overall, these es-
tablishments amount to a gradual and pre-
dictable rate of species accumulation that
could result in devastation of nearby agri-
cultural environments by the pest species.
Some introductions will be recognized im-
mediately for their potential (e.g., Medfly
and other fruit flies). However, others will
not manifest themselves immediately. The
following case history exemplifies how a
relatively subtle urban introduction could
develop into a serious agricultural problem.
Japanese Bayberry Whitefly
The Japanese bayberry whitefly, Para-
bemisia myricae (Kuwana), is found in Tai-
wan, the Philippine Islands, and the southern
islands of Japan. Although the whitefly has
been intercepted many times in Hawaii
(from the Philippines), no evidence indicates
that it has become established there. It was
listed as a serious pest of mulberry in areas
of Japan in the 1920's and is also a minor
pest of citrus. The species, however, is well
controlled by natural enemies in Japan and
in the Philippines.
The whitefly was collected for the first
time in the western hemisphere from a
nursery in Santa Ana, Orange County, Cali-
fornia. Specimens of the insect were col-
lected from Gardenia on 6 October 1978 by
agricultural inspectors during a routine nur-
sery inspection. Independently, Los Angeles
agricultural inspectors discovered the same
species on Robinson naval orange during a
routine inspection of a wholesale nursery in
San Gabriel on 12 October 1978. A Los
Angeles County entomologist, having been
informed of the Orange County find, recog-
nized the whitefly and sent it to Sacramento
for confirmation. Subsequent inspection of
the San Gabriel nursery resulted in discov-
eries of this insect on Robinson naval or-
ange, Dancy tangerine, Bearss lime, Marsh
grapefruit, Eureka lemon, Washington or-
ange, and dwarf birch.
By 6 November 1978, the bayberry
whitefly had been found in two nurseries and
their urban environs in Orange County and
in two wholesale nurseries and their urban
environs in Los Angeles County. The known
infested area in Los Angeles covered 35
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244
square miles. Further, the wholesale nur-
series were shipping infested nursery stock
to other counties in California and to Ari-
zona.
By 11 November delimitation surveys re-
vealed the whitefly's presence in nurseries
in El Cajon, Encenitas, and La Jolla in San
Diego County; Hesperia in San Bernadino
County; Carpinteria in Santa Barbara
County; Bakersfield, Delano, and Oakdale in
Kern County; Fresno in Fresno County; and
Lafayette in Contra Costa County (and two
locations in nurseries in Phoenix, Arizona).
The infested area in Los Angeles extended
some 200 square miles.
On 15 November 1978, a committee met
to determine a course of action. The com-
mittee felt that further data was needed
before a sound decision could be made.
They postponed any recommendation for ac-
tion for 60 days. The likelihood of success-
ful chemical eradication already seemed re-
mote. Based on previous experiences with
eradication of the woolley whitefly, AZeuro-
thrixus floccosus (Maskell), the committee
estimated that the cost of chemical eradi-
cation for this new whitefly would amount
to about 16.5 million dollars over a six-year
period. Further, eradication would require
the application of about 17.5 million pounds
of insecticide. In view of the expected cost,
the already widespread distribution, and the
good biological control of the pest in Japan
and the Philippines, the CDFA in January
decided to take no further chemical control
or quarantine action. Rather, a biological
control program was suggested as an alter-
native and was initiated through the Uni-
versity of California.
By 22 November 1978 the pest potential
of the species in California was already well
recognized. It had been found on 45 plant
species including citrus, avocado, and decid-
uous fruit trees. By late 1979, populations
began to increase substantially on many
hosts. By June 1980, a large block of
commercial lemons in Orange County be-
came so heavily infested that insecticide
treatments were required. On lemons the
growth patterns of the cultural pruning
practices meant that the trees produced
new growth almost constantly, an attribute
preferred by this whitefly. By early 1981,
many lemon groves throughout southern
California were heavily infested.
Due to the whitefly's short life cycle in
California (21 days under greenhouse condi-
tions) and its ability to reproduce parthen-
ogenetically, the whitefly can develop large
populations rapidly and can spread quickly
from place to place. The early stages are
small and without the noticeable wax adorn-
ment typical of other whitefly species. It is
therefore difficult to locate in low densities
during delimitation surveys.
The Japanese bayberry whitefly story
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245
exemplifies the difficulty of finding, con-
trolling, or eradicating an insect pest in an
urban environment. When the initial infest-
ation was discovered, it was too large to
eradicate. Biological control was the only
logical alternative. Unfortunately, to date
biological control has not been very effec-
tive in either commercial orchard or urban
situations in California. This may be due to
rapidly developing and dispersing popula-
tions which do not allow natural enemies to
keep pace. It may also be due to poor
acclimatization by recently introduced
natural enemies. Hopefully, biological con-
trol will eventually reduce the whitefly pop-
ulations.
SOCIO ECONOMIC AND POLITICAL
IMPACTS
Where eradication efforts are mounted
against exotic pests, eradication must also
be conducted in urban areas. Although the
pest in question may be of greater concern
to agricultural or forest interests than to
urban residents, such eradication efforts
must be conducted by the ground rules of
the urban, not rural, situation. Even in
states whose principal industries are agri-
culture or forest products, vocal and highly
organized efforts to compromise proposed
"optimum" eradication programs can be ex-
pected from today's more informed and
sophisticated urban citizenry.
Recent U.S. events concerning toxic
chemicals and human health virtually dic-
tate that decision-makers seriously examine
the attitudes of urbanites towards standards
of environmental quality as they relate to
pest management. Findings from a recent
national poll by Louis Harris (as reported in
Sierra, Vol. 67(4), 1982) exemplify relevant
aspects of these attitudes. For example, an
overwhelming majority of people, 83%,
"want the Clean Air Act enforced as strictly
as it is today or even more so." A majority
of 65% to 32% also say they oppose any
constraint on human helath standards on
grounds of cost! Of considerable signifi-
cance to the politics of decision-making is
the fact that, fully 45% of the voters
nationwide say that the way a candidate for
Congress voted on clean air would probably
or certainly affect their vote for that candi-
date this fall [1982], even if they agreed
with him or her on most other issues. When
probed further, Harris found that "33% of
the voters this fall are prepared to defeat
candidates for Congress who yield on Clean
Air." In another national survey on environ-
mental issues, conducted by the Council on
Environmental Quality (CEQ 1980), pollsters
learned that 46% of the interviewees were
greatly worried about "the presence of toxic
chemicals such as pesticides or PCB's in the
environment" (see also Levenson and
Frankie 1981).
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246
When these survey findings are con-
sidered in light of other socioeconomic and
politiacl patterns (e.g., voting strength is in
urban rather than in rural areas, and public
involvement in decision-making is increas-
ing), one may expect a wider array of pest
management decisions in the future. One of
these options, that of no action, will in-
creasingly be given serious consideration.
This situation in turn should place much
greater pressure on research and extension
institutions to provide urbanites with high-
quality information on the costs and bene-
fits of eradication and/or management op-
tions.
CONCLUDING REMARKS
This treatise is the first step towards
understanding the processes that lead to the
introduction and establishment of pest or-
ganisms in urban environments. Future in-
quiry into this topic might include such
matters as:
1. Elucidating the characteristics of intro-
ductions and establishments (e.g., fre-
quency of urban vs. agricultural intro-
ductions) of a greater representation of
pest organisms in California and other
states where accurate records are com-
piled.
2. Developing generalizations about intro-
ductions and establishments based on
case history accounts from several
states. These case histories should also
include the socioeconomic and political
circumstances associated with the intro-
ductions and establishments.
3. Assessing current nursery practices (in-
cluding assoicated regulations involving
movemnets of plant materials) that may
be responsible for some introductions.
4. Surveying attitudes of people who trans-
port plant materials across international
and state boundaries. Some effort to
survey these attitudes has already been
attempted by federal quarantine author-
ities (G. Snider, pers. comm.).
5. Examining pest faunas on native and
exotic plant species in given urban areas.
Do natives or exotics, for example, have
more pest problems (including plant
pathogens)? Further, what are the pros-
pects for using biological control agents
against exotics and natives (see Ehler
1982)?
ACKNOWLEDGEMENTS
We thank K. Brown, G. Buxton, H. Fair-
child, K. Hansgen, A. Hardy, and G. Snider
for providing us with unpublished informa-
tion and insight into many of the problems
associtated with introduced pest organisms.
FOOTNOTES
1
Based on records of the California Depart-
ment of Food and Agriculture.
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247
One square mile policy: The State of
California administers and operates a
pest prevention system mandated by
Section 403 of the Food and Agriculture
Code. Its major components are: pest
exclusion, pest detection, pest eradica-
tion, and public information and educa-
tion. Pest detection involves systematic
searches for specific pests outside of a
known infested area. The goal is to
detect incipient infestations before er-
adication becomes biologically or eco-
nomically uinfeasible. In the case of
insects, the goal is to detect pests (and
take appropriate action) before the in-
festation exceeds 1 square mile.
3
Many other pest groups, including poten-
tially serious pests such as termites and
wood-infesting beetles from overseas
crating material, are similarly char-
acterized and treated in the same man-
ner (D. Dilley and R. Gill, pers. observ.).
4
Two errors should be noted in the biocon-
trol narrative of the NAS report. The
second complete paragraph on page 15
should begin with: "Fifteen pests were
the targets of classical biological control
from 1890-1969 (Laing and Hamine
1976)."
The third complete paragraph on page
151 should begin with: "In contrast, 106
agricultural, medical/veterinary, forest, and
greenhouse pests were the targets for clas-
sical biological control."
REFERENCES
APHIS. 1979. List of intercepted plant
pests (from July 1, 1973 through Sep-
tember 30, 1977). USD A, APHIS publ.
82-5.
APHIS. 1980. List of intercepted plant
pests (from October 1, 1977 through Sep-
tember 30, 1978). USDA, APHIS publ.
82-6.
APHIS. 1981. List of intercepted plant
pests (from October 1, 1978 through Sep-
tember 30, 1979). USDA, APHIS publ.
82-7.
CEQ. 1980. Public opinion on environ-
mental issues (Results of a national pub-
lic opinion survey). A publication of the
Council on Environ. Quality, USDA,
DoE, and EPA.
Ehler, L.E. 1982. Ecology of Rhopalomyia
californica Felt (Diptera: Cecidomyii-
dae) and its parasites in an urban envi-
ronment. Hilgardia 50:1-32.
Frankie, G.W. and L.E. Ehler. 1978. Ecolo-
gy of insects in urban environments.
Ann. Rev. Entomol. 23:367-387.
Frankie, G.W., J.B. Fraser and V.R. Lewis.
1982. Suggestion for implementing sur-
vey research results that deal with pub-
lic attitudes and behavior towards arth-
ropod pests in urban environments.
Proc. of Symp. on Urban and Suburban
Tree Health. Michigan State Univ., E.
Lansing (in press).
Gill, R.J. 1979. A new species Pulvinaria
Targioni-Tozzetti (Homoptera: Cocci-
dae) attacking ice plant in California.
Pan-Pac Entomol. 55:241-50.
-------
248
Hoy, M. 1982. The gypsy moth - here
again. Calif. Agric. 36:4-6.
Levenson, H. and G.W. Frankie. 1981. Pest
control in the urban environment. In: T.
O'Riordan and R.K. Turner (eds.) Pro-
gress in Resource Management and Envi-
ronmental Planning. John Wiley and
Sons, Ltd., England.
NAS. 1980. Urban Pest Management. A
report of the committee on urban pest
management. National Research Coun-
cil. National Academy Press.
Nelson, B.C. 1978. Ecology of medically
important arthropods in urban environ-
ments. In: G.W. Frankie and C.S.
Koehler (eds.) Perspectives in Urban
Entomology, pp. 87-124.
Olkowski, W., H. Olkowski, A.I. Kaplan and
R. van den Bosch. 1978. The potential
for biological control in urban areas:
shade tree insect pests. In: G.W.
Frankie and C.S. Koehler (eds.) Perspec-
tives in Urban Entomology, pp. 311-
347.
Roth, L.M. and E.R. Willis. 1960. The
biotic associations of cockroaches.
Smithson. Misc. Collect. 141.
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249
Table 1. Numbers of introduced homopteran species that have established in
California environments and their probable sites of introduction (see
also Appendix I).
Family
Nos. of species
intro. erad. estab.
a
Probable intro. site
Urban Agric. ?
Aleyrodidae
Coccidae
Diaspididae
Pseudococcidae
Totals
7
29
84
29
149
0
4
30
_4
38
6
25
51
21
105
7
22
72
^6
127
0
4
12
_2
18
0
3
0
I
4
a
lSpecies not accounted for through eradication efforts, apparently died out.
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250
Table 2. Introduced and established species of selected homopteran families;
dates of first discovery in California; current status in California.
Taxa
Aleyrodidae
Aleurocybotus occiduus Russell
Aleurothrixus floccosus (Maskell)
Aleurotuba jelinekii (Frauenfeld)
Aleurotulus nephrolepidis (Quaintance)
Dialeurodes citri (Ashmead)
Parabemisia myricae (Kuwana)
Pealius azaleae (Baker <5c Moles)
Coccidae
Ceroplastes ceriferus (Fabricius)
C. cirripediformes Comstock
C. cistudiformis Cockerell
C. floridensis Comstock
C. sinensis Del Guercio
Coccus hesperidum Linnaeus
C. longulus (Douglas)
C. pseudohesperidium (Cockerell)
C. pseudo m agnoli arum (Kuwana)
Eucalymnatus tessellatus (Signoret)
Eulecanium caryae (Fitch)
Parasaissetia nigra (Nietner)
Parthenolecanium corni (Bouche)
Parthenolecanium fletcheri (Cockerell)
P. persicae (Fabricius)
P. Pruinosum (Coquillett)
P. quercifex (Fitch)
Physokertnes hemicryphus (Dalman)
Protopulvinaria pyriformis (Cockerell)
Pulvinaria citricola Kuwana
P. delottoi GUI: DeLotto Icepl. scale
P. floccifera (Westwood)
P. hydrangeae Steinweden
P. m esembryanthemi (Vallot):Icepl. scale
P. vitis (Linnaeus)
Saissetia coffeae (Walker)
S. miranda (Cockerell & Parrott)
Probable
intro.
site8
Comm. turf
Urb
Urb
Nurs
Nurs
Nurs
Nurs
Urb
Urb
Urb
Urb
Urb
Urb
Urb
Urb
Ag-Citrus
Urb
Ag-fr
Nurs
Ag-fr
Nurs
Urb
9
Nurs
Urb
Urb
Urb
Urb
Urb
Urb
Urb
Ag-fr
Urb
9
First
discovery
inCAD
pre 1950
post 1950
post 1950
pre 1950
pre 1950
post 1950
pre 1950
pre 1950
pre 1950
pre 1950
post 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1900
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950 .
post 1950°
pre 1950
pre 1950 .
post 1950°
pre 1950
pre 1950
pre 1950
Current
status0
MP
SP
MP
DO
MP or CP
SP
R
Erad
Yard pest
R
Erad
Yard pest
CP
R
Erad
Citrus pest
DO
R
R
MP
R
R
Walnut
pest
Oak pest
(minor)
R
MP
Erad
MP or CP
R
R
CP
R
MP or CP
MP
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251
Table 2. (cont'd)
Taxa
S. oleae (Olivier)
Toumeyella liriodendri (Gmelin)
Diaspididae
Abgrallaspis cyanophylli (Signoret)
A. degeneratus (Leonardi)
Acutaspis albopicta (Cockerell)
Andaspis mackieana (McKenzie)
Aonidia lauri (Douche)
Aonidiella aurantii (Maskell)
A. citrina (Coquillett)
A. taxus Leonardi
Aspidiotus destructor Signoret
A. nerii Bouche
A. spinosus Comstock
Aulacaspis rosae(Bouche)
Carulaspis" juhiperi (Bouche)
C. minima (Targioni-Tozzetti)
Chionaspis americana Johnson
C. etrusca Leonardi
C. furfura (Fitch)
C".gleditsiae Sanders
C. wistariae Cooley
Chrysomphalus aonidum (Linnaeus)
C. bifasciculatus Ferris
£• dictyospermi (Morgan)
Clavaspis disclusa Ferris
C. ulmi (Johnson)
Comstockiella sabalis (Comstock)
Diaspidiotus liquidambaris (Kotinsky)
Diaspis boisduvalli Signoret
D. bromeliae (Kerner)
D. coccois Lichtenstein
Dynaspidiotus britannicus (Newstead)
Epidiaspis leperii (Signoret)
Fiorinia fioriniae (Targioni-Tozzetti)
F. japonica Kuwana
F. pinicola Maskell
F. theae Green
Furchadaspis zamiae (Morgan)
Hemiberlesia palmae (Cockerell)
Probable
intro.
site*
Urb
Urb
Urb
Urb
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Urb
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Ag
Urb
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Urb
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
First
discovery
inCAD
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1900
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
Current
status6
SP
U Erad
R
R
Erad
Erad
Erad
SP
MP or CP
Erad
Erad
SP
R
MP or CP
R
MP
R
CP
Erad
Erad
R
DO
R
DO
7
R
DO
MP
SP
R
R
•>
Walnut
pest
R
Erad
Erad
Erad
MP or CP
Erad
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252
Table 2. (cont'd)
Taxa
H. lataniae (Signoret)
H. rapax (Comstock)
Howardia biclavis (Comstock)
Kuwanaspis pseudoleucaspis (Kuwana)
Lepidosaphes beckii (Newman)
L. camelliae Hoke
L. chinensis Chamberlin
L. conchiformis (Gmelin)
L. destefani Leonard!
L. gloverii (Packard)
L. machili (maskell)
L. noxia McKenzie
L. pallida Maskell
L. sciadopitysi McKenzie
L. tokionis (Kuwana)
L. ui'mi (Linneaus)
Leucaspis portaeaureae Ferris
Lindingaspis rossi (Maskell)
Lopholeucaspis cockerelli (de Charmoy)
Melanaspis bromeliae (Leonardi)
M. obscura (Comstock)
Neopinnaspis harperi McKenzie
Nilotaspis halli (Green)
Odonaspispenicillata Green
O. ruthae Kotinsky
Parlatoreopsis chinensis (Marlott)
Parlatoria blanchardii (Targioni-Tozzetti)
P, camelliae Comstock
P. crotonis Douglas
P. oleae (Colvee)
P. pergandii Comstock
P. pittospori Maskell
P. proteus (Curtis)
P. theae Cockerell
Pinhaspis aspidistras (Signoret)
P. buxi (Bouche)
P. strachani (Cooley)
Pseudauiacaspis cockerelli (Cooley)
Probable
intro.
sitea
Nurs
Nurs
Nurs
Nurs
Ag-Citrus
Nurs
Nurs
Ag-Figs
Ag-Olives
Ag-Citrus
Nurs
Nurs
Nurs
Nurs
Nurs
Ag-fr
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Ag-fr
Nurs
Nurs
Nurs
Ag-Dates
Nurs
Nurs
Nurs
Ag-Citrus
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
First
discovery Current
in CAD status0
pre 1950 MP or CP
pre 1950 MP or CP
pre & post Erad
1950
pre 1950 R
pre 1900 MP
pre 1950 R
pre 1950 Erad
pre 1950 MP
pre 1900 MP
pre 1950 R
pre 1950 R
pre 1950 Erad
pre 1950 Erad
pre 1950 Erad
pre 1950 Erad
pre 1900 MP
pre 1950 R
pre 1950 MP
pre 1950 Erad
pre 1950 R
pre 1950 R
pre 1950 R
pre 1950 Erad
pre 1950 MP
pre 1950 MP
pre 1950 R
pre 1950 Erad
pre 1950 R
pre 1950 Erad
pre 1950 MP
pre & post Erad
1950
pre & post R
1950
pre & post Erad
1950
pre 1950 Erad
pre 1950 MP
pre 1950 Erad
pre 1950 Erad
pre & post Erad
1950
-------
253
Table 2. (cont'd)
Taxa
Probable
intro.
sitea
First
discovery Current
in CA status0
p. pentagona Targioni-Tozzetti
P. parlatorioides (Comstock)
Quadraspidiotus forbesi (Johnson)
Q. juglans-regiae (Comstock)
§. perniciosus (Comstock)
jlenaspidus albus McKenzie
S. articulatus (Morgan)
S. rubidus McKenzie
Una'spi's euonymi (Comstock)
Ag-fr
Nurs
Ag-fr
Ag-fr?
Urb
Nurs
Nurs
Nurs
Nurs
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
pre 1950
Erad
Erad
R
MP or CP
SP
R
Erad
R
MP or CP
Pseudococcidae
Antonina graminis (Maskell)
A* pretiosa Ferris
Brevennia rehi (Lindinger)
Cataenococcus olivaceus Cockerell
Chorizococcus brevicruris McKenzie
C. lounsburyi Brain
Crisicpccus azaleae (Tinsley)
C. pini (Kuwana)
DysmicoGGUs brevipes (Cockerell)
D. mckenziei Beardsley
Ferrisia virgata (Cockerell)
Heterococcus nudus (Green)
Hypogeococcus splnosus Ferris
Nipaecoccus aurilanatus (Maskell)
N. nipae (Maskell)
Phenacoccus aceris (Signoret)
P. graminicola Leonard}
Planococcus citri (Risso)
P. kraunhiae (Kuwana)
fieudantonina arundinariae McConnell
Pseudoccus calceolariae'Waskell)
P. comstocki (KuwanaT"
P. importatus McKenzie
P. longispmus (Targioni-Tozzetti)
P. microcirculus McKenzie
Rhizoeeus dianthi Green
R. falcifer Kunckel d'Herculais
R, kondonis Kuwana
Trionymus diminutus (Leonardi)
Nurs
Nurs
•)
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Ag-Comm.
turf?
Nurs
Nurs
Nurs
Nurs
Urb-Comm.
turf?
Ag-Citrus
Nurs
Nurs
Ag
Urb
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
Nurs
post 1950 DO
pre 1950 MP
post 1950 MP or CP
post 1950 R
post 1950 Erad
pre 1950 MP
pre 1900 R
pre 1950 MP or CP
pre 1950 R
post 1950 Erad
post 1950 MP or CP
pre 1950 R
pre 1950 R
pre 1950 MP or CP
pre 1950 R
post 1950 U Erad
pre 1950 MP
pre 1900 SP
pre 1950 DO
post 1950 Erad
pre 1950 MP
post 1950 CP
post 1950 Erad
pre 1950 MP or CP
post 1950 U Erad
post 1950 MP or CP
pre 1950 MP or CP
post 1950 SP
pre 1950 R
-------
254
«j
Ag = agricultural; Comm. turf = commercial turfgrass; Nursery (Comm. turf &
Nursery within or directly adjacent to urban areas).
Renovation and modernization of CA quarantine/detection service occurred
1950.
CMP = minor pest; CP = common pest; SP = serious pest; R = rare; DO = died out;
Erad = eradicated; U Erad = under eradication.
In 1949 a collection of Pulvinaria sp. was taken from ice plant at the U.C.
Botanical Garden, Berekley; it subsequently could not be relocated (between
1949-70). Then, in the early 1970's two scale species, P. delottoi and P.
mesembryanthemi, were found on isolated plantings of ice plant in the northern
San Francisco Bay Area. Although the 1949 Pulvinaria specimens very closely
resembles P. delottoi, it is not considered conspecific at this time.
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255
Table 3. The most economically important insect and mollusc pests that have
been eradicated from Californiaj dates and location (County) of first
discovery. With the exception of numbers 3, 5, 7 and 9, all species were
discovered in urban areas.
First discovery date
Counties
white garden snail
obscure snail
Mexican bean beetle
Mexican fruit fly
wheat sawfly
melon fly
Khapra beetle
Japanese beetle
Khapra beetle
white garden snail
Japanese beetle
medfly
gypsy moth
medfly
oriental fruit fly
1929 Orange and Los Angeles
1933 Los Angeles
1950 Ventura
1954 San Diego
1954 Santa Barbara
1956 Los Angeles
1960 Fresno, Tulare, San Francisco, Madera,
King, Los Angeles, Kern, Imperial,
Riverside, and San Bernardino
1961 Sacramento
1966 Imperial
1970 Los Angeles
1973 San Diego
1975 Los Angeles
1977 Santa Clara
1980 Los Angeles
1960 Orange
1960 Santa Barbara
1966 Orange
1967 Orange
1969 Los Angeles
1970 Los Angeles
1970 Orange
1971 Orange and San Diego
1972 Santa Barbara and Orange
1973 Los Angeles
1974 Los Angeles
1975 San Diego
1976 Los Angeles and San Diego
1977 Orange and Los Angeles
1980 Orange and San Diego
a
Hall scale, Nilotaspis halli. which is a serious Homopteran pest (see also Appendix
I), was discovered in 1952 in Butte and Yolo Counties (agric. environs). It was
subsequently eradicated.
•U.S. OOmjMEN! PBIHIINO OJMOE I 1982 0-389-890/70
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