Pests resistant to pesticides and genetically modified crop plants: Theory and management

The theories behind insect and weed resistance management for Bt and herbicide tolerant crops are similar to those for managing chemical insecticide and herbicide resistance. A resistance management plan for a Bt crop must take into consideration the unique biology and behavior of the target insect as well as the details of the cropping system. Thus, plans developed for Bt corn and cotton in the United States and canada are likely not applicable to other crops and other countries. Beyond the theoretical aspects, resistance management plans must be workable and practical so that farmers can implement the guidelines. A resistance management plan is not static-it is a "living" document, and it may need to change as new data is collected or unique situations arise. A resistance management plan will not completely eliminate the possibility that resistance will emerge. It is a tool to slow resistance development, preserving Bt as long as possible as a pest management tool. Pest resistance management must be viewed within the context of integrated pest management (IPM). If IPM is successfully adopted and implemented, the objective of resistance management will be automatically achieved (Maredia 1997).