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OCR for page 371
6
Implementing Management of
Resistance to Pesticides
PEST-CONTROL DECISIONS are influenced by many institutions, regula-
tions, laws, and economics. This chapter focuses on the current status
of efforts to manage development of resistance to pesticides and rec-
ommends how strategies to manage resistance might be implemented. In-
dividuals and single companies are limited in their ability to deal with resistance
primarily because: (1) resistant pests move across property boundaries, (2)
information on the current and prospective pesticide susceptibility levels of
pest populations is expensive to assemble, (3) information on methods for
managing resistance and actions to respond to resistance are often needed at
many locations at the same time, involving several related compounds made
by different companies, and (4) because of potential conflicts of interest,
combined with companies' needs for proprietary secrets. In responding to
these difficult challenges, we will assess the roles of public agencies, groups
of private firms, and the market system in managing resistance.
Once tactics for slowing pesticide resistance are developed and tested,
technical progress will be achieved only if the tactics are properly, widely,
and consistently applied. Four of the more important groups of organizations
that affect implementation are: (1) the extension service, pest-management
consultants, and farmers (considered here as a group); (2) regulatory agencies;
(3) the pesticide industry; and (4) international organizations.
This report focused on the biological and genetic bases of resistance and
on tactics to manage resistance. The committee recognized that few of the
standard institutional mechanisms and incentives are available to bring about
changes needed to encourage use of these tactics, which are often specific
to particular pests and/or crops. To coordinate activities to manage resistance,
371
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372
MANAGEMENT OF RESISTANCE TO PESTICIDES
it may be possible to build on existing initiatives such as the National Bio-
logical Impact Assessment Program (NBIAP).
EXTENSION, CONSULTANTS, AND PESTICIDE USERS
Education
The Cooperative Extension Service should take a leadership role in de-
veloping educational programs in the area of management of resistance to
pesticides, coordinating input from state agricultural experiment stations,
pest-control advisers, the pesticide industry, commodity associations, reg-
ulatory agencies, and end users. Factors to consider in a training program
are
· The known toxicological, genetic, biological, and operational factors
that influence selection for resistance. Published studies should be used as
the primary basis for anticipating situations where resistance might occur.
· Identify and categorize pests and pesticides at high risk for developing
resistance, particularly those that can develop cross-resistance.
· Review integrated pest management-compatible tactics-such as re-
ducing selection pressure- that delay resistance development. Stress inte-
grating pesticide use with nonpesticidal control measures. Discuss the high
value of retaining, for as long as possible, low-cost pesticides that are used
successfully in integrated-pest-management (IPM) programs.
· Emphasize the value of monitoring for resistance. Action thresholds
should be established that determine the frequency of the population that is
resistant at any time and above which it is advisable to switch to an alternative
pesticide. Examples of action thresholds for development of resistance are
described elsewhere in this volume (Fr~sbie et al.~.
RECOMMENDATION 1. The Extension Committee on Organization and Pol-
icy IPM Task Force should conduct a feasibility study for developing an
educational program on management of pesticide resistance, coordinated
through the Cooperative Extension Service.
This committee should work with representatives from the state agricultural
experiment stations, U.S. Department of Agriculture-Agricultural Research Ser-
vice (USDA-ARS), Economic Research Service (ERS), Animal and Plant Health
Inspection Service (APHIS), professional societies, industry, consultant orga-
nizations, commodity organizations, public health agencies, and state depart-
ments of agriculture to determine whether a program thrust in this area is needed
and feasible, and, if so, what the form and function of the training program
should be.
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MANAGEMENT OF RESISTANCE TO PESTICIDES
Formalize Procedures for Management of Resistance to Pesticides
373
There may be a need to formalize and standardize procedures for dealing
with resistant pest populations, as discussed by Frisbie et al. (this volume).
When a control failure occurs, farmers, agricultural consultants, chemical
applicators, state agricultural experiment stations, and Cooperative Extension
services should work with agricultural chemical companies to determine the
basis for the failure. A series of questions need to be addressed in a logical
order: was the most effective pesticide applied for the specific pest and life
stage; was it applied at an appropriate rate; was it applied under favorable
weather conditions; did the equipment function properly; is the toxic agent
active. If any of these conditions were not met, corrective actions should be
taken. If the control failure persists, a bioassay should then be used to
determine whether the pest population is susceptible to the pesticide. When
resistance is verified at a level sufficient to justify alternative control strat-
egies, they should be used immediately, if possible. Additional research is
needed to establish action thresholds for resistance for specific pests and
crops, and to develop pest-specific rapid bioassay and monitoring techniques
(see Chapters 2 and 4.) When appropriate management tactics (see Chapter
5) are developed and validated, they should be implemented by the appro-
priate groups mentioned above.
RECOMMENDATION 2. A formalized procedure or action plan should be
developed to manage resistance to pesticides and to identify responsible
individuals or agencies. The Cooperative Extension Service should take the
leadership role in organizing work groups within state, regional, and na-
tional IPM programs to implement management of resistance.
REGULATORY AGENCIES
This section concerns U.S. state and federal agencies. The committee
focused on actions that could be undertaken to manage resistance without
major legislative changes in state laws or in the Federal Insecticide, Fungicide
and Rodenticide Act (FIFRA), the primary federal statute governing the
registration and use of pesticides in the United States.
When resistance occurs, what is the appropriate role of state and federal
agencies currently regulating pesticide use? Use directions and prohibitions
against certain practices might be added to pesticide labels to prolong the
useful life of a pesticide. As reliable methods become available, "resistance-
risk" data might be required as part of the pesticide registration process and
used in developing educational materials for certifying and training users and
sellers of pesticides. As a first step, the mode of action should be identified.
The recent experience of applying biotechnology to herbicides suggests that
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MANAGEMENT OF RESISTANCE TO PESTICIDES
mode of action can be determined quite rapidly. Information on pesticide
resistance often becomes available as part of other regulatory activities-
reregistration, applications for emergency use exemptions, and regulatory
actions taken to prohibit certain pesticide uses. Questions remain regarding
what should be done with this information and how funds should be generated
for regulatory activities, information collection, and research.
Pesticide Resistance in Regulatory Decisions
The committee agreed that resistance management is a legitimate activity
for regulatory agencies when beneficial strategies and program opportunities
arise, but recognized that there are strengths and weaknesses in each regu-
latory initiative considered. At the present time, the committee does not
recommend major changes in state or federal regulatory responsibilities as
they relate to resistance.
In the committee's judgment, there are compelling reasons why resistance
is a difficult phenomenon to integrate more formally or routinely into reg-
ulatory agency decision-making. These include (1) federal agencies cannot
make or implement timely decisions for local management of resistance; (2)
market participants, local groups, and extension services can monitor and
more effectively direct management; and (3) regulatory agencies lack funding
for new management initiatives because they have higher priority pesticide
regulatory objectives to pursue.
The U.S. Environmental Protection Agency (EPA) pesticide-use regula-
tions under FIFRA do not explicitly direct the agency to consider resistance
in carrying out its other responsibilities. In practice, though, the statute's
basic risk-benefit balancing criterion requires consideration of pesticide ef-
ficacy in determining benefits. To the extent resistance reduces actual or
anticipated efficacy and hence benefits-EPA is already mandated to take
it into account. Resistant pest populations, moreover, affect definitions of
emergency use conditions, classification of pesticides, and reporting of "ad-
verse effects" all part of the regulatory process. Any biological factor,
such as resistance, that can substantially reduce the benefits from pesticide
use could affect some regulatory decisions. Still, as a practical matter, it
would be difficult to encourage use of strategies to manage resistance by
specifying such strategies on pesticide product labels, the major instrument
available to regulatory agencies for encouraging resistance management.
Because most pesticide resistance events are localized and change rapidly,
use of pesticide labels to help manage resistance will rarely be feasible
(Johnson, Hawkins, this volume).
Several approaches, however, do exist to encourage management of re-
sistance. The practice of allowing market forces to reward product efficacy
is well established for most pesticide products. (Johnson, this volume, dis
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MANAGEMENT OF RESISTANCE TO PESTICIDES
375
cusses efficacy waivers under FIFRA.) There are possibilities, as well, for
the extension service, agricultural consultants, and pesticide firms to monitor
for and recommend management strategies in local areas.
Finally, in considering the regulatory approach to managing resistance to
pesticides, the constraints on available resources must be recognized. For a
regulatory approach to be effective, it must be timely and specific as to
location, crop, and pests. Consideration of mixtures and multiple compounds
so that rotations might be used would require considerable manpower, which
is not currently available in the EPA. Health and environmental risks could
increase if EPA and state resources were shifted from pesticide safety to
managing resistance and maintaining pesticide product life.
The economic conditions under which individual pesticide firms, groups
of firms, or farmers can profitably act to reduce resistance are limited by
pest mobility and market structure. The following conditions are thought to
favor mandatory or government programs in resistance management (Mir-
anowski and Carlson, this volume): (1) when noncooperation by one or more
chemical firms can jeopardize a regional program to manage resistance; (2)
when antitrust considerations make certain cooperative efforts between firms
difficult, and perhaps illegal; (3) when coordination between firms is costly,
such as might occur when many companies or farmers with widely different
interests in managing a pest population are involved; or (4) when a govern-
ment unit is directly responsible for pest control, such as for public health
pests or on public lands managed by the Forest Service.
The increasing number of pesticide resistance incidents (i.e., human health-
related pests in hospitals, malaria mosquitoes, isolated rat populations, and
certain agricultural pests such as the Colorado potato beetle) is frequently
cited as a reason for government regulations in risk management. The in-
creased cost of synthesizing new chemicals to replace those chemicals made
obsolete by resistance also affects the availability and cost of chemical pes-
ticides. Increased safety testing has increased pesticide registration time and
costs of bringing new pesticides to market (CAST, 19811. Cross-resistance
can also make it more difficult to develop new chemicals; there is concern
in some quarters that we may be running out of biochemical or physiological
target sites in pests that can be attacked by new chemicals. New biological
techniques, however, are expected to enable us to identify additional target
sites not heretofore recognized. Pesticide companies and growers are con-
cerned about the very limited set of products in many cases, just one or
two registered compounds available to control many major pests.
On the other hand, indicators of future scarcity of pesticides such as
pesticide prices in broad classes of pesticides do not give signals of increasing
rates of resistance development. Pesticide prices have been falling relative
to the prices of other agricultural inputs over the past 15 years (Miranowski
and Carlson, this volume). Pesticide prices are an important indicator of
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376
MANAGEMENT OF RESISTANCE TO PESTICIDES
resource scarcity in the future even in the presence of market imperfections.
One is cautioned, however, that examining changes in pesticide prices prob-
ably will not reveal and correlate with high levels of resistance on minor
crops and/or pests. Also not revealed are important pest resistance episodes
(rodenticides, dipter~cides) in poor regions or countries.
Frequently, government agencies can assist in resistance management by
carrying out other regulatory and research functions. For example, the EPA
has had a program supporting IPM research; as a part of IPM, efforts to
manage resistance to pesticides is clearly a legitimate function of government.
California and a few other states have been active in funding research to
understand resistance to pesticides, with a goal of developing practical pro-
grams to reduce its buildup (Hawkins, this volume).
In cases where pesticides are approved only for experimental or emergency
use, evaluation of pesticide use ideally should precede approval for com-
mercial registration or at least be in progress while the application is being
considered. Monitoring is critical to evaluation of both experimental and
emergency pesticide-use programs. While accurate monitoring is expensive
and virtually impossible to administer on a global scale (see Chapter 4, this
volume), it should be possible on a smaller scale; it should include regular
estimates of densities and distribution of pest, extent of pest-related damage,
and frequencies of resistant pest genotypes. The latter should be obtained
for pests in the surrounding area as well. Programs to obtain similar estimates
should also be instituted for a few representative areas where pesticides are
already being applied.
RECOMMENDATION 3. Departments of agriculture within each state, in
considering whether to request emergency use permits to respond to pest-
control needs that have arisen because of resistance to another compound,
should seek advice on whether the conditions governing the emergency use
permit are consistent with validated tactics for the management of resis-
tance. The EPA, in approving such requests, should also consider the con-
sequences for managing resistance, especially when cross-resistance is thought
to be a possibility.
The committee agreed that the idea of requiring data on "resistance risk" as
part of the pesticide registration requirements is currently inappropriate. Con-
siderable research is needed before the feasibility of such data requirements can
be established, and such a regulatory response would require significant resource
commitments at the EPA. Whenever such data exist, however, regulatory agen-
cies should use them in discussing potential pesticide benefits (Dover and Croft,
this volume).
RECOMMENDATION 4. Major reforms in regulatory programs do not ap-
pear justified or feasible at this time to advance the management of resistance
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MANAGEMENT OF RESISTANCE TO PESTICIDES
377
to pesticides. Administrators of regulatory agencies should, however, for-
mally enunciate policy statements that indicate awareness of, and respon-
siveness to, resistance management issues, to the extent that such factors
can and must be considered when implementing regulatory activities. Ac-
tivities to manage resistance should not be pursued to the extent that they
divert program resources from high priority safety responsibilities.
R,?.vi.~tance Management Information in Regulatory Agencies
The committee does feel strongly that a legitimate function of regulatory
agencies is the collection and dissemination of information on resistance to
pesticides. Information on the efficacy of particular pesticides is critical for
making informed pesticide-use decisions.
Because of their contact with farmers, extension service personnel and
other local groups are in the best position to help producers formulate de-
cisions to manage resistance. Given the frequent necessity for quick responses
to resistance development by farmers, consultants, and chemical firms, how-
ever, the reporting of a resistance episode to regulatory agencies could prob-
ably not be acted on fast enough for a regulatory agency to initiate steps to
foster resistance management, at least in the current production year.
It is very costly to monitor and determine the geographical boundaries of
a resistant pest population. A company often may not even know that resis-
tance exists. Sometimes, firms may be reluctant to reveal diminution of
pesticide effectiveness, but it is very difficult to conceal resistance in the
United States for long. On the other hand, though, the desire for repeat sales
of a pesticide product, and for sales of other products in the company's
product line, generally leads companies to respond quickly to assess and
report the extent of resistance to pesticides.
Nevertheless, regulatory agencies can help foster solutions to pesticide
resistance by compiling and disseminating accurate information. Various
EPA functions, such as granting of emergency use registrations and the
"adverse effects" activities, currently have important impacts on information
flow. Resistance to available pesticides is reported in about 30 percent of
the documents filed with the EPA by state agencies requesting emergency
use registrations (section 18 of FIFRA).
Compiling information on resistance in an easy-to-access computer file
and disseminating this to a repository within the USDA, such as the National
Pesticide Information Retrieval System, could be useful. Because of the local
nature, variable severity, and important time dimensions of resistance, it is
difficult at present for state and federal programs to obtain information and
respond quickly. Furthermore, there is no reliable mechanism in place to
validate the accuracy of resistance information. Therefore, any steps to com
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MANAGEMENT OF RESISTANCE TO PESTICIDES
pile and publish resistance data should proceed only in conjunction with an
effective mechanism to update and confirm its accuracy.
RECOMMENDATION 5. Information collection and dissemination on pesti-
cide resistance is an important function of federal agencies involved with
agriculture. A new initiative in carrying out this function should be pursued.
The EPA, the USDA, and state regulatory agencies should cooperate in
building a permanent repository for such information, including a mecha-
nism to confirm the accuracy of resistance data.
Reports published by the Food and Agricultural Organization (FAO) and the
World Health Organization (WHO) validate resistance episodes and could per-
haps serve as a useful model in establishing a repository for resistance data.
Funding
Funding constraints must be confronted in structuring new initiatives to
manage resistance. The EPA and state regulatory agencies appear to have
little flexibility to reduce or adjust other program responsibilities in pesticide
regulation. As stated earlier, the committee feels that safety-related pesticide
regulatory activities should retain higher priority than resistance management.
Therefore, public funds through regulatory channels for resistance manage-
ment are limited. Resistance monitoring, information dissemination, and
research activities will require both public and private programs.
One idea advanced at the convocation for raising new funds to advance
resistance management is imposition of a national sales tax on pesticides. In
supporting such a tax, proponents argue that the pesticide industry and users
of pesticides will be the primary beneficiaries of successful resistance man-
agement and that they should defray through such a tax the costs to develop
and maintain programs to manage resistance.
There is no indication that pesticide companies or farmers feel that resis-
tance development and management needs are critical enough in the United
States to justify such a tax. Pesticide firms have been surveyed and are nearly
unanimously opposed to such a tax. No careful assessment of farmers is
available, although the committee suspects that farmers without resistance
problems will probably not be eager to bear the brunt of such a tax through
higher pesticide prices since the tax would finance research and extension
related to resistance for other regions or countries.
Many resistance problems have only local impacts, and these can usually
be met with new pesticides or nonpesticide approaches, including wider
adoption of integrated pest management. Farmers may approve localized user
fees for managing resistance, as occurs with community pest-management
user fees used to fund integrated pest management, pest eradication, and
management of resistance to pesticides for mosquitoes. Such fees are assessed
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MANAGEMENT OF RESISTANCE TO PESTICIDES
379
on crop acreage (for example, cotton insect eradication programs), land area
(property tax), and production level (cotton bale taxes), with local growers
having a direct role in controlling how the funds are used.
Pesticide manufacturers have incentives to join with other pesticide firms,
university researchers, and the extension service to provide research and
information on resistance. Industry is expanding voluntary efforts to report
resistance. To date there have been no major financial assessments.
RECOMMENDATION 6. Redirection of EPA funding or imposition of a na-
tional pesticide tax are not recommended. Pesticide taxes collected by local
pest-control districts can be used to manage resistance and should be en-
couraged.
PESTICIDE INDUSTRY
Most major pesticide firms are active in many countries, and actions taken
in one country reflect its unique crops, pests, social institutions, and laws.
In recent years, pesticide companies in groups and individually have increased
actions to reduce the rate of resistance buildup and to prolong the market
lives of pesticides. Several organizations of pesticide firms have come into
existence over the past 4 or 5 years with management of resistance as their
major purpose. A currently successful example of this voluntary cooperative
program among companies occurred in Australia with the goal of managing
development of resistance to synthetic pyrethroids by cotton bollworms (He-
liothis armigera) (Davies, 19841.
Economically, the willingness of a particular company to take actions to
reduce resistance development for a given pesticide is related to market
structure, pest mobility, and cost and returns of employing resistance man-
agement tactics. The value of protecting a pesticide from resistance is affected
by: number, effectiveness, and costs of existing and prospective, competitive
pesticides; expense of nonchemical controls; ease of production of the com-
pound; and effectiveness in controlling major pestles) on major coopts).
Groups of pesticide firms have joined together, with some successes, to
prevent or forestall the emergence of resistance for certain classes of pro-
prietary pesticides. Such action has been possible only where coordinated
activities are not costly or illegal, and when coordination across pesticide
products was mutually recognized as essential to prevent resistance to val-
uable products. With cross-resistance, or production of a single compound
by several companies, cooperative efforts between firms may be used for
monitoring, research, and in deployment of control tactics such as use of
mixtures, recommendations for use of selective pesticides, and rotation of
pesticides. The basic notion is that by joining efforts areas large enough to
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380
MANAGEMENT OF RESISTANCE TO PESTICIDES
treat mobile pest populations effectively can be combined (Miranowski and
Carlson, this volume).
Antitrust Concerns
Agreements between firms to divide up territories, customers, or time
periods are usually considered illegal, especially in developed countries with
mature market economies. Even if the intent of a group of firms is to regulate
sales of a class of pesticides to prevent development of resistance, such group
actions could be ruled anticompetitive, although the committee is aware of
no such case. Companies are reticent to try collaborative activities, but
individually or jointly they can take action that is not anticompetitive in order
to reduce selective pressure on a pest population. Three actions that have
either been tried or considered are (1) recommendations in addition to label
directions by a firm on use patterns of its product to prevent resistance (such
recommendations would, though, have to be consistent with labels or risk a
violation of FIFRA), (2) joint recommendations to end users (farmers, public
health agencies) by a group of firms on pesticide-use patterns over time and
space, and (3) attempts by a firm or firms to influence or amend the regis-
tration of products by regulatory agencies (discussed below).
Recommendations on rotation or mixtures of pesticides can either be issued
directly by the company or funneled through the extension service, a local
government agency, or private consultants. Because such a program is only
a recommendation to users, who still have the right to buy and use any
registered compound at any time in a manner consistent with its label direc-
tions, recommendations to rotate or mix pesticides are not considered to be
anticompetitive. Such a program requires considerable cooperation among
users and sellers of pesticides.
RECOMMENDATION 7. After consultation with the EPA; university, state,
and federal researchers; and industry trade associations, the U.S. Justice
Department should consider issuing a voluntary ruling that clarifies the
anti-trust consequences (if any) of joint pesticide use recommendations by
groups of pesticide companies offered for the purpose of reducing devel-
opment of resistance to pesticides.
Registering Pesticide Mixtures
Pesticide registration decisions can affect resistance. For example, there
are occasions when mixtures are a valid management strategy, and such a
strategy can be recommended with confidence for use over a wide area.
Indeed, mixtures of pesticides are routinely used, consistent with EPA-ap-
proved labels on existing products, on some crops to control pest complexes
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MANAGEMENT OF RESISTANCE TO PESTICIDES
381
that are not controllable with any single pesticide. Regulatory agencies need
to be flexible and to review the merits of new label application and warning
proposals quickly. Use of labels to mandate specific use patterns should be
discouraged because such recommendations are not appropriate in all regions
where a given pesticide is used.
At the same time, industry representatives should not attempt to use the
registration process to conceal changes in pesticide efficacy from pesticide
users or competitors. If a label is obtained that only allows a mixture of two
compounds to be applied for a given pest, and if resistance has been developed
to one of these compounds in some locales, then farmers in the areas with
resistance may be induced to use an ineffective compound. In addition, a
requirement that only mixtures be used could increase the amount of pesticide
released in the environment.
Research on the use of pesticide mixtures to reduce development of re-
sistance is in progress, but is not sufficiently advanced to support definitive
recommendations at this time. Compatibility of pesticides as mixtures and
selectivity of pesticides in controlling pests and pest complexes continue to
be important topics for research.
Coordination of the research, use recommendations, and regulation of
pesticide mixtures is needed. Requiring use of mixtures by only selling
pesticides in this form is a severe restriction, and it should only be adopted
if research demonstrates the mixture's desirability in managing resistance.
RECOMMENDATION 8. The EPA should adopt a flexible policy on registra-
tion of pesticide mixtures. Coordination among regulatory agencies, re-
search groups, and pesticide companies is needed when requests for registration
of mixtures are proposed.
Minor-Use Pesticides
Resistance can exacerbate shortages of pesticides in crops with small acreages
and specialized pests. New pesticide introductions have been encouraged in
minor-use groups by a program known as Interregional Project-4 (IR-41. The
JR-4 program encourages input by universities and other groups in developing
residue chemistry, efficacy, and phytotoxicity data for obtaining tolerances
and product registrations. The program strives to lower the cost of registration
for minor uses so that these markets are not bypassed when a chemical firm
is expanding the crops and pests included on its label. In several instances,
the JR-4 program has been successful in supporting minor-use registrations
needed because of resistance to pesticides.
The JR-4 program can serve as a model for new efforts to encourage public
sector activity in resistance management programs. If a pesticide firm has
particular use instructions it wishes to include on the label, then the firm can
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MANAGEMENT OF RESISTANCE TO PESTICIDES
provide authorization and financial support for university research so that a
prescribed program to manage resistance is available to farmers. Efforts on
the part of the USDA and universities need not be limited to residue analysis
and short-term efficacy tests. Longer-term efficacy studies related to resis-
tance management could also be included.
The JR-4 program has been effective over the past 20 years because it
shares data across regions and facilitates close cooperation between the pes-
ticide industry, grower organizations, and state and federal laboratories. The
EPA has assisted by providing financial support, handling JR-4 petitions as
priority actions, and promulgating specific guidelines for the registration for
food and nonfood uses. Efforts to address minor-use problems faced outside
of agriculture have been extremely limited. There is interest on the part of
industry to include rodenticides, disinfectants, and other human health pests
in this program. Resistance problems are particularly severe in some non-
agricultural pests, so new approaches and funding are both needed and jus-
tified.
RECOMMENDATION 9. Expansion is encouraged of the JR-4 activities to
include pesticide registration activities related to resistance. Expanding the
JR-4 concept to nonagricultural minor uses should be pursued by state and
federal agencies.
INTERNATIONAL CONSIDERATIONS
Pesticide resistance is a global problem. Resistant pest populations are not
restricted by geographical boundaries, and major pesticide manufacturers
operate in all parts of the world, often selling comparable products to control
the same pestles) on four continents. Large-scale movement of people and
goods among countries increases the likelihood that resistant pest populations
become internationally established. This is especially true in developing
regions where quarantine and inspection services are often lacking or inef-
fective. The less-developed countries are particularly vulnerable to disease
and severe economic losses from pesticide resistance. Agricultural devel-
opment efforts, although often constrained by resistance in agricultural pest
populations, have not generally received the attention directed toward resis-
tance problems due to failures in disease vector control programs that affect
public health programs.
Because the United States plays a large role in world agriculture, and U.S.
policies are highly visible, management actions taken by the U.S. to limit
resistance to pesticides can affect the global development of resistance. Global
consequences should be considered in developing legislative and adminis-
trative changes in U.S. pesticide-use policy.
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MANAGEMENT OF RESISTANCE TO PESTICIDES
Roles of International Organizations
383
FAO and WHO These U.N. organizations are made up of member coun-
tries. Their roles in managing resistance to pesticides are to
· Encourage and assist member countries to develop and use effective,
accurate monitoring systems to detect resistance.
· Provide member countries with technical assistance to analyze and in-
terpret existing information to determine the significance of resistance epi-
sodes that are detected, and potential implications for field-level programs.
· Facilitate the collection and dissemination of information on resistance
to pesticides.
· Assist all countries to carry out research on countermeasures for resis-
tance by directly funding or by stimulating relevant research projects.
· Assist in training and education for effective management of resistance
to pesticides.
The FAO regards resistance problems and related strategies as an inherent
part of IPM programs. It can neither intervene nor interfere with national
policies of member countries on pesticide registration or other regulatory
matters. If requested, though, it can provide available guidelines and assist
in securing external expertise. An international Code of Conduct on the
Distribution and Use of Pesticides, now under preparation, will provide
further international guidance on appropriate responses to pesticide resistance
problems.
For 30 years, management of resistant disease vectors has been a high
priority of WHO, which considers vector resistance the greatest technical
impediment to control of these diseases. The problem has become even more
critical in recent years as human pathogens have developed resistance to
major drugs. Where no vaccine or effective drugs are available for mass
treatment, WHO's public health programs must rely on vector control. Ac-
cordingly, WHO has developed 13 standardized tests for the susceptibility
of major disease vectors to important pesticides. The WHO program for
detecting and monitoring resistance involves interpreting and analyzing test
results, feedback, periodic reporting, and follow-up advisement to member
countries. All monitoring and detection information is stored on computer
files; incidence and distribution trends are summarized and reported every 5
years at meetings of WHO's Expert Committee on Insecticide Resistance.
Countries where resistance is detected receive an alert and are advised to
study the epidemiological picture to see if resistance is impeding progress
of disease-control efforts. This action may ultimately lead to the development
of new methods or new materials for vector control. WHO's current focus
on training and education is designed to alleviate a lack of trained profes-
sionals in many member countries.
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MANAGEMENT OF RESISTANCE TO PESTICIDES
The World Bank This institution may affect resistance to pesticides through
its investments in agricultural development or public health projects that
provide funds for pesticide purchase. World Bank officials have issued guide-
lines to determine whether projects with major pesticide purchases are likely
to provide a positive return on investment and encourage sound safety and
pest-management practices. Development of these guidelines is an important
step for pest-control investments in developing countries, and the World
Bank should be encouraged to apply them in addressing likely pesticide
resistance problems.
CGIAR International Research Centers The international research cen-
ters are autonomous, commodity-oriented, and focus primarily on methods
for increasing productivity through germ plasm research. While it is not
within the mandate of these centers directly to address resistance issues, the
importance of good pesticide management is recognized within many of the
centers' model or better programs. IPM strategies are used in these programs
partly as a measure to prevent development of resistance.
Need for U.S. Support While the concerns and programs of a number
of international organizations contribute to greater global integration of man-
agement of resistance to pesticides, several problems constrain their effec-
tiveness:
· A lack of data on pesticide use and pesticide performance in less-
developed countries limits opportunities to assess the likelihood of resistance
to specific materials developing in specific pest populations. Lack of such
information makes it difficult to develop criteria for pesticide-dependent
investments or to make wise selections of pesticide materials for use in
development and public health programs.
· Information on the incidence of resistance needs to be more effectively
collected and summarized, better targeted, and more broadly disseminated.
· Appropriate decision-making based on accurate information requires
well-trained people. The current level of training is inadequate in many less-
developed countries, and training opportunities are limited by a lack of
resources.
Private and public decision-making in the United States is affected by
inadequate information on global incidence of resistance to pesticides. As
part of the international community, the United States depends on the main-
tenance of global pest susceptibility to important pesticides. The U.S. Agency
for International Development (AID) provides some assistance in the areas
of pesticide management, training, and improved pest management to less-
developed countries and regions with which it deals. The AID policy on
pesticides requires that AID projects minimize pesticide use and encourage
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MANAGEMENT OF RESISTANCE TO PESTICIDES
385
an integrated approach to pest management, but availability of funds can
limit the extent to which this policy is implemented.
RECOMMENDATION 10. The United States should support increased in-
volvement and larger-scale organized efforts to coordinate information sys-
tems and research on resistance to pesticides. To the extent possible, the
United States should provide funding and personnel to achieve increased
training and education on pesticide management and pesticide resistance in
less-developed countries.
The potential benefits of these courses of action for the United States are a
decreased rate of global development of resistance and an increased ability to
react rapidly to accurate information about new cases of resistance in domestically
important pest species. The USDA-OICD (Office of International Cooperation
and Development) and AID should take a lead role in providing personnel and
funding in pursuit of this goal.
impact of U.S. Policy
No international organization or institution has regulatory authority for
pesticide use. The influence of U.S. policymaking on pesticide-regulating
programs in other nations is thus critical.
Both U.S. domestic pesticide use and international aid policies can affect
perceptions or use of specific pesticide materials in other countries. The EPA
registration process sends signals to other countries regarding U.S. judgment
on benefits and risks of particular pesticides. Regulation 16 of the Code of
Federal Regulations (part 216, Pesticide procedures; also codified in Section
118 of the Foreign Assistance Act) requires that any AID international as-
sistance project involving pesticides be reviewed through an environmental
impact statement (EIS). The preparation of an EIS, and its outcome, are
based partly on the EPA's registration status of proposed pesticides. The
process is more stringent for materials that are not registered for use in the
United States.
FAO and WHO programs, and the public health and agricultural control
programs in less-developed countries, rely heavily on inexpensive, practical,
and effective pesticides. Actions taken by the United States on pesticide use
or management of resistance can affect this reliance, especially when such
actions tend to limit access in the developing nations to older, cheaper, generic
chemicals that have retained efficacy for decades of use in the developed
world.
· Actions that conserve the susceptibility of important pests to major
pesticides aid third world goals by decreasing the global rate of resistance
development.
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386
MANAGEMENT OF RESISTANCE TO PESTICIDES
· Policies that limit the global availability of particular pesticides can
constrain less-developed countries' abilities to manage resistance.
Constraints on global availability of certain pesticides have come about
because of cancellation or suspension actions taken in the United States.
U. S. pesticide regulations are based on national priorities and relatively strict
environmental standards. Some materials banned in the United States are
considered essential for achieving public health or agricultural development
goals in less-developed countries possessing different national priorities.
Additionally, the United States must be aware that less-developed countries
may adopt U.S. regulations with little or no analysis or modification, even
in cases where such regulations are inappropriate. Vast differences in insti-
tutions, agricultural systems, and cultural and political factors, however, can
make U.S. policies on pesticide use or management of resistance to pesticides
inappropriate or counterproductive for other countries.
RECOMMENDATION 11. U.s. policy recommendations or policies specific
to U.S. priorities should contain qualifications that clearly limit their ap-
plicability to the current domestic situation. Assistance should be provided
by AID and EPA in helping less-developed countries formulate pesticide
· ~
po Icles.
REFERENCES
CAST (Council for Agricultural Science and Technology). 1980. Impact of government regulations
on the development of chemical pesticides for agriculture and forestry. Report No. 87. Ames,
Iowa: CAST.
Davies, R. A. H. 1984. Insecticide resistance: An industry viewpoint. Pp. 593-600 in Proc. 1984
Br. Crop Prot. Conf., Pests and Dis.
WORKSHOP PARTICIPANTS
Implementing Management of Resistance to Pesticides
GERALD A. CAR~soN (Leader), North Carolina State University
ARNo~D AsPE~N, U.S. Environmental Protection Agency
CHARLES M. BENBROOK, National Research Council
Lungs CHIARAPPA, Food and Agriculture Organization of the United Nations
CHAR~Es J. DELP, E. I. duPont de Nemours and Company
MICHAEL J. DOVER, World Resources Institute
STAN FERTIG, U.S. Department of Agriculture
RAYMOND E. FR~ss~E, Texas A&M University
NORMAN GRATZ, World Health Organization, Switzerland
LYNDON S. HAwK~Ns, California Department of Food and Agriculture
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MANAGEMENT OF RESISTANCE TO PESTICIDES
RICHARD HERRErr, ICI Americas, Inc.
MAUREEN HINKEE, National Audubon Society
EDWIN L. JOHNSON, U.s. Environmental Protection Agency
JOHN A. MIRANOWSKI, U.s. Department of Agriculture
KATHERINE REICHEEDERFER, U.s. Department of Agricultur
PATRICK WEDDEE, Weddle, Hansen and Associates
KEN WEINSTEIN, McKenna, Conner and Cuneo
387
e
Representative terms from entire chapter:
resistance management
