SUSTAINABILITY OF TRANSGENIC INSECTICIDAL CULTIVARS - INTEGRATING PEST GENETICS AND ECOLOGY

This review examines potential impacts of transgenic cultivars on inse ct population dynamics and evolution. Experience with classically bred , insecticidal cultivars has demonstrated that a solid understanding o f both the target insect's ecology and the cultivar's performance unde r varied field conditions will be essential for predicting area-wide e ffects of transgenic cultivars on pest and natural enemy dynamics. Thi s experience has also demonstrated the evolutionary capacity of pests for adaptive response to insecticidal traits in crops. Biochemical and genetic studies of insect adaptation to the Bacillus thuringiensis (B t) toxins expressed by currently marketed transgenic cultivars indicat e a high risk for rapid adaptation if these cultivars are misused. The oretical and practical issues involved in implementing strategies to d elay pest adaptation to insecticidal cultivars are reviewed. Emphasis is placed on examining the ''high dose''/refuge strategy that has beco me the goal of industry and regulatory authorities.