Pesticide Resistance Strategies and Tactics for Management (1986) / Chapter Skim
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Factors Influencing the Evolution of Resistance
Factors Influencing the Evolution of Resistance
Pages 157-169
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From page 157... ...
For example, despite enormous selection pressure during many years of intensive DOT treatment in the corn belt of the United States, the corn borer showed no evidence of resistance. Yet house flies in many areas developed resistance 157
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From page 158... ...
Even within a species, resistance may develop more rapidly in one population than in another. The Colorado potato beetle, for example, showed far greater propensity for resistance on Long Island than on the mainland (Forgash, 1981, 1984)
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From page 159... ...
In some cases these issues may be addressed in laboratory studies where resistant strains can be developed by selection on large, recently colonized populations. Nonetheless, some factors that influence the evolution of resistance are under man's control, especially those related to the timing and dose of insecticide application (Operational Factors, Table 11.
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From page 160... ...
More important, the selection pressures and immigration rates may impose an unstable equilibrium of gene frequencies, below which resistance alleles decrease in fitness and above which they increase (Haldane, 19301. In this case the initial frequency is especially important.
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From page 161... ...
With few exceptions resistant populations demonstrate lower fitness than their susceptible counterparts. Continued selection may improve fitness through coadaptation of the resistant genome, resulting in more stable resistance.
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From page 162... ...
The Colorado potato beetle also provides a pertinent example. On Long Island the population of this species required seven years to develop resistance to DDT, the first synthetic insecticide with which it was selected.
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From page 163... ...
Diabrotica longicornis, Amphimallon majalis, and Popillia japonica, each with one generation per year, have required 8 to 14 years for resistance development, while the sugarcane wireworm (Melanotus tamsuyensis) in Taiwan, with a two-year life cycle, has taken 20 years to develop resistance.
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From page 164... ...
Polyphagous insect pests tend to develop resistance more slowly than monophagous ones. Two factors may contribute to this: A smaller part of polyphagous species are likely to be exposed, hence the selection is less intense on these species; because some of the insects would be in untreated refugia, they would provide a reservoir from which untreated, susceptible migrants could come.
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From page 165... ...
Whatever the reason, such refugia may be very important in providing a source of susceptible immigrants, thus retarding evolution (Georghiou and Taylor, 19761. The eriophyid mite Aceria sheldoni, which inhabits citrus buds, has been controlled for several years with chlorobenzilate and has yet to develop resistance.
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From page 166... ...
Our simulations, using quantitative genetic models, indicate that there is little difference if one works under the constraint of a constant selection differential. The available experimental evidence also suggests that there is little difference.
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From page 167... ...
1981. Effects of insecticidal selection and treatment on reproductive potential of resistant, susceptible, and heterozygous strains of the southern house mosquito.
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From page 168... ...
1984. Estimation of the relative viabilities of insecticide resistance genotypes of the Australian sheep blowfly, Lucilia cuprina.
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From page 169... ...
1983. A note on estimating selection pressures on insecticide resistance genes.
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