摘要：When the application of pesticides places selective evolutionary pressure on pest populations, itcan be useful to plant refuge areas—crop areas intended to encourage the breeding of pests that aresusceptible to the pesticide. Renewed interest in refuge areas has arisen with recent advances inbiotechnology and genetically modified (GM) crops. In this paper, we use a simple model of the evolutionof pest resistance to characterize the socially optimal refuge strategy for managing pest resistance. Wedemonstrate some interesting analogies with other models of renewable resource management, such asthose of fisheries. Among the analogous results are findings that maintaining what we might call"maximal sustainable susceptibility" is typically not economically optimal and that the stock of pesticideeffectiveness maintained is a declining function of the discount rate. The former result is in contrast tosome existing studies based solely on biological considerations. We also examine the land useconsequences of the enhanced agricultural productivity that results from the use of GM crops. Argumentsare frequently encountered to the effect that GM crops could reduce the total area required for agricultureand thereby increase the quantity of land conserved for natural habitat. We show that the situation maynot be as simple as standard arguments portray it. If refuge areas are used to manage resistance, then moreland will be devoted to agriculture than would be the case were it simply a matter of adopting atechnology that offered the same yield per hectare without requiring the management of a biological stocksuch as pest susceptibility.
