Pesticide Resistance Strategies and Tactics for Management (1986) / Chapter Skim
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Chemical Strategies for Resistance Management
Chemical Strategies for Resistance Management
Pages 111-129
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From page 111... ...
Administrative changes also might foster increased research activity in these areas or might increase the probability that novel approaches will be developed by the agrochemical industry or otherwise be made available for use in integrated pest-management programs. INTRODUCTION The Critical Role of Insecticides in Insect Control The overuse and misuse of insecticides have caused target pest resurgence, secondary pest outbreaks, and environmental contamination (Metcalf and McKelvey, 19761.
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From page 112... ...
Such procedures constitute the most fundamental approach to resistance management by minimizing the selection pressure leading to resistance. Reduced pesticide use not only decreases selection pressure on pest insects but preserves natural enemies and other nontarget species, reduces environmental contamination, reduces the exposure of farm workers and consumers to potentially toxic materials, and may reduce phytotoxicity.
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From page 113... ...
Thus, rather than removing us from a "pesticide treadmill," IPM and resistance management will only slow the treadmill, thereby extending the usefulness of available chemicals. Integrated pest management also requires new insecticides.
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From page 114... ...
Costs of Production Increased chemical complexity increases production costs. Recently introduced compounds require expensive starting materials, multistep syntheses, isomer separations, and sometimes the preparative resolution of optical isomers.
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From page 115... ...
A related approach is to de-emphasize insecticide development and to emphasize development of materials such as herbicides that are perceived to be less risky or less expensive to register. For example, some of the explosive growth of industrial research in agricultural biotechnology has been at the expense of research on crop chemicals.
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From page 116... ...
Although these compounds may be registered for other uses, they are often forced into secondary uses for which they are not well-suited. This narrow targeting severely limits the diversity of insecticides available for use in pest management.
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From page 117... ...
For enhanced detoxication the challenge is simply to develop microanalytical techniques to determine the level of activity of enzymes of interest in individual insects. Simple microassays can also be developed for one major type of intrinsic insensitivity, such as the altered cholinesterase involved in organophosphate and carbamate resistance.
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From page 118... ...
Discovering New Insecticides Approaches to Finding and Optimizing Biological Activity The agrochemical industry is very skilled at optimizing the biological activity of a series of chemicals (Magee, 1983; Menn, 19831. Recent technological advances, many of which have been adopted by industrial research laboratories, are certain to refine and enhance this expertise.
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From page 119... ...
The current industrial effort to develop avermectins, a group of fungal toxins with high insecticidal activity, illustrates that a very complex molecule can be made by a fermentation process that is competitive with classical industrial chemistry. This concept greatly expands the variety of structural types that might be used commercially for insect control and indicates that rigorous screening of plant and microbial natural products may meet with still further success.
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From page 120... ...
These resistance mechanisms cannot be overcome by synergists. Resistance management strategies based on rotating compounds that differ in their sites of action have not been tested in the field and are limited by the lack of diversity of sites of action in our current armament of insecticides.
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From page 121... ...
Once high biological activity is discovered, such selectivity can be developed by synthesizing compounds to exploit differences in xenobiotic metabolism or simply by testing a series of chemicals on pest and beneficial insects as part of the evaluation process. Just as industry invested in resistance management when it became financially advantageous, many companies will eventually include selectivity as a major criterion in the future selection of compounds.
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From page 122... ...
He concluded that "simultaneous achievement of safety, environmental, and productivity objectives in insect pest control will require that the public sector play a larger role in research and development." National Institutes of Health and the National Science Foundation If gold stars were to be awarded to agencies for funding work leading to the discovery of new targets for insecticide development, the National Institutes of Health (NIH) and the National Science Foundation (NSF)
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From page 123... ...
Nevertheless, EPA has funded some of the most exciting and innovative work on the development of new insecticides; it has also funded research that will improve environmental quality and encourage implementation of IPM programs. Certainly, research that leads to the discovery and development of insect control agents that promise fewer environmental and nontarget problems is a logical extension of the above programs.
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From page 124... ...
would cost $3 million per year, a modest amount compared to the nearly $20 million increase recently designated to establish funding through the Competitive Grants Program for research in agricultural biotechnology. Despite the need for this type of funding, the future of the entire Competitive Grants Program is regularly threatened in the budget process.
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From page 125... ...
The major commitment that a university must make is to hire faculty to work in the area of target biochemistry and physiology. It takes more than a two-week short course to convert an organic chemist into a creative leader of a biorational pesticide development program.
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From page 126... ...
Companies must establish sufficient inhouse expertise in insect biochemistry and physiology and must initiate basic research programs that are relevant to the company's objectives and complementary to university research efforts. The agrochemical industry tends to hire basic scientists and then assumes that basic research is simply the screening of experimental chemicals on an elegant in vitro preparation.
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From page 127... ...
An effort by EPA to process registration petitions as rapidly as possible would be of great benefit, particularly if extensions in patent life cannot be obtained. Changes in the ways in which toxicological risks are evaluated would promote the development of novel, selective compounds.
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From page 128... ...
If, however, an increase in our knowledge of the biochemistry of target species and the impact of new technologies can decrease the cost of discovery, if the time and cost of regulatory compliance can be minimized without detriment to the public good, and if patent lives of compounds can be extended to compensate for marketing time lost in regulatory review, then the search for and development of novel insecticides will be perceived to be a sound, profitable business, and the tremendous potential that we see for the development of safe and selective pesticides by both chemical and molecular approaches will be realized. ACKNOWLEDGMENTS This work was supported by NIEHS Grant ES02710-05, Research Career Award 5 K04 ES500107, and a grant from the Herman Frasch Foundation to Bruce D
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From page 129... ...
ln Biological Control in Agricultural Integrated Pest Management Systems, M
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