Incorporating resistance in pesticide management: a dynamic regional approach

Pesticide resistance in agricultural systems has been recognised as one of the world’s top environmental problems for nearly two decades (UNEP 1979). Occurring in over 500 species of insects (Georghiou 1990), resistance is a genetic phenomenon whereby resistance-conferring genes accumulate in pest populations. Agricultural producers contending with pests that reduce the quality and/or quantity of outputs apply pesticides to increase profits or to decrease income variability. As resistance begins to accumulate, however, these treatments become less effective. Attempting to maintain expected crop yield, producers typically apply additional pesticide applications, yet over time, this practice compounds the problem by increasing environmental selection for resistant traits (Croft and Dunley 1993).