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3 Population Biology of Pesticide Resistance: Bridging the Gap Between Theory and Practical Applications
Pages 143-156

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From page 143...
... Similarly, relatively few investigators involved in management of resistance have directly applied the tools and theoretical concepts of academic population biology. In this chapter we describe current attempts at bridging the gap between academic and applied population biology, discuss aspects of the genetics and population biology of resistance critical to developing resistance management programs, recommend future work needed in this area, and describe major impediments to developing and implementing programs to manage resistance.
From page 144...
... The total number of pesticides required for this cycling depends solely on the lengths of the resistance onset and susceptibility recovery intervals (Figure 11. In this model, the goal of resistance management is to maximize the resistance onset intervals and minimize the susceptibility recovery intervals.
From page 145...
... . GENETIC AND ECOLOGICAL INFORMATION REQUIRED FOR MODELS OF THE POPULATION BIOLOGY OF RESISTANCE Even though specific resistance management programs should be designed on a case-by-case basis, the following general classes of information are required to develop realistic models of the population biology of pesticide resistance, and thus to design resistance management programs:
From page 146...
... the duration of the whole life cycle and its various stages. The lengths of both the resistance onset and susceptibility recovery intervals depend in
From page 147...
... The intensity of selection for and against resistant genotypes could be greatly affected by the nature of the trade-off between density-dependent and density-independent mortality and morbidity factors. Where there is substantial intraspecific competition, sublethal doses of a pesticide could have a strong selection effect by weakening the competitive abilities of susceptible individuals, even when it does not control the density of the population (McKenzie et al., 19821.
From page 148...
... . Obtaining DNA and RNA probes is not easy when the gene product is not known or known and present in low quantities, or when the physical location on the gene of the model organisms is not known, but molecular techniques should be considered for determining modes of inheritance for population studies of pesticide resistance.
From page 149...
... . EVALUATING MODELS AND PROGRAMS FOR PESTICIDE RESISTANCE MANAGEMENT While we may believe that existing studies of the fit between theory and empirical observation justify the use of population biology theory to develop pesticide use and resistance management programs, a final demonstration of their utility remains necessary.
From page 150...
... Even if the original resistant genotypes had a marked disadvantage in the absence of the pesticide, there may be selection for modifier genes that improve the fitness of resistant genotypes. The limited empirical results on the fate of alleles conferring resistance following termination of pesticide use support a mixed view of the fate of resistance genotypes in the absence of pesticide selection.
From page 151...
... If pesticide resistance is the result of inserting movable elements of chromosomes, then conceivably the initial transposition could increase the future rates of transposition. In cases where resistance to specific pesticides requires two mutations, one in a gene that is common to resistances to different compounds and one that is unique to each, mutation could appear to be directed.
From page 152...
... More extensive breakdown of the traditional separation between applied and academic biology would be a major step toward the solution to the pesticide resistance problem as well as other biological-technical problems. We see no easy general solution to this problem.
From page 153...
... While it may be a long-term goal to develop precise analogs of specific pesticide-use situations, population biology theory may be applied to develop pesticide-use regimes before specific models are developed. The fact that general population biology theory has been successful in a retrospective manner, by providing mechanistic explanations for past resistance episodes, justifies the use of this theory in a prospective manner.
From page 154...
... Pesticide resistance is a long-term problem that will require the coordinated efforts of investigators representing several disciplines that currently suffer from a lack of interdisciplinary communication. While unlikely to be sufficient as a unique solution to the problem of coordinating efforts, some funds specifically earmarked for joint basic and applied research on the population biology of pesticide resistance may help surmount some of the institutional impediments to this type of interdisciplinary activity.
From page 155...
... 78:25-29. WORKSHOP PARTICIPANTS Population Biology of Pesticide Resistance.
From page 156...
... 156 POPULATION BIOLOGY OF PESTICIDE RESISTANCE BRUCE E TAsAsHN~K, University of Hawaii MARCY UYENOYAMA, Duke University SARA VIA, University of Iowa MAX J


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