Factors contributing to brown planthopper resurgence.

There have been significant advances in noninsecticidal pest management. Insecticides, however, are still indispensable to rice farmers because they are effective, easy to use, and provide immediate results. Synthetic organic insecticides provide effective insect control, but their widespread use has resulted in toxicity to natural pest enemies, toxic residues in plants and the environment, and insect resistance. Resurgence of some pests after insecticide application on rice is becoming common. Such an abnormal increase in the pest population after insecticide application often far exceeds the economic injury level. Insecticide-induced pest outbreaks have been reported in walnut (Barlett and Ewart 1951), hemlock (McClure 1977), soybeans (Shepard et al 1977), and cotton (Bottrell and Rummel 1978). Among the pests infesting rice, the brown…