ABSTRACT
Plant resistance to insects has evolved over millions of years, and considerable progress has been made in development and deployment of crop plants with resistance to insects. Counter adaptation by the herbivores to the resistance mechanisms, and the response of the natural enemies to the insect-resistant plants and the insect host determine the outcome of such a complex interaction (Sharma and Waliyar, 2003). Such an interaction is also infl uenced by the abiotic environmental factors. The intentional selection and breeding for resistance to insects has led to the development of insect-resistant cultivars in several crops and as a result the need to apply insecticides for insect control has been reduced considerably. Insect-resistant cultivars are in general compatible with the natural enemies, although plant resistance at times can have detrimental affects on the activity and abundance of natural enemies. The latter has not received any adverse publicity, as the adverse effects of insect-resistant cultivars on the nontarget organisms are still far less than those of broadspectrum insecticides used for pest management, which may result in complete elimination of the natural enemies of crop pests.
