ABSTRACT

Transgenic cotton that expresses the Cry1Ac protein for the control of lepidopteran insect pests (Bt cotton) has been commercialized in nine countries and is grown on over 5 million acres worldwide. Insect Resistance Management (IRM) is an important part of the global stewardship of this technology. The IRM needs for Bt cotton vary among countries because of differences in pest biology, farming practices, and farmer literacy and experiences. In this paper, we discuss these differences, and how they affect and constrain IRM options with particular reference to the refuge strategy. As an illustration, we contrast the need for farmer-planted refuges in the United States with smallholder-dominated agricultural systems in India and South Africa where alternative crop and weedy hosts, respectively, serve as natural refuge for Bt cotton.