Biological Control in the Management of Planthopper Populations
Biological control is “the utilization of natural enemies to reduce the damage caused by noxious organisms” (DeBach and Rosen 1991). Although the ultimate goal is damage reduction, biological control of insects relies on the suppression of pest populations through the action of natural enemies, that is, predators, parasites, and pathogens (Smith 1919). Ecological theory has provided a context for understanding the dynamics of pest-enemy interactions and examples of biological control have been used to test ecological theory (Hassell and May 1974; Ehler 1976; Beddington et al. 1978; Waage 1990). Population dynamics theory concerns just how a wide variety of factors including natural enemies interact to influence population size (Price 1984). The practice of biological control involves manipulation of natural enemies within agroecosystems to achieve a level of suppression defined on socioeconomic criteria. Despite this difference, population dynamics theory has proved useful in the development of practical biological control. For example, the prediction of pest population dynamics has been improved (e.g., Nilaparvata lugens Stål by Hirao 1979b) and testable hypotheses concerning pest-enemy dynamics have been provided (e.g., Chesson and Murdoch 1986).
KeywordsSugar Migration Toxicity Corn Depression
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