Sustainability of Transgenic Insecticidal Cultivars: Integrating Pest Genetics and Ecology

TLDR

Experience with classically bred insecticidal cultivars shows that understanding target insect ecology and cultivar performance across field conditions is essential for predicting area‑wide effects of transgenic cultivars on pest and natural enemy dynamics. This review examines the potential impacts of transgenic cultivars on insect population dynamics and evolution, and discusses theoretical and practical issues for delaying pest adaptation. The authors review strategies to delay pest adaptation, emphasizing the high‑dose/refuge approach promoted by industry and regulatory authorities. Pests have demonstrated evolutionary capacity to adapt to insecticidal traits, and biochemical/genetic studies reveal a high risk of rapid adaptation to Bt toxins if transgenic cultivars are misused.

Abstract

This review examines potential impacts of transgenic cultivars on insect population dynamics and evolution. Experience with classically bred, insecticidal cultivars has demonstrated that a solid understanding of both the target insect's ecology and the cultivar's performance under varied field conditions will be essential for predicting area-wide effects of transgenic cultivars on pest and natural enemy dynamics. This 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 (Bt) toxins expressed by currently marketed transgenic cultivars indicate a high risk for rapid adaptation if these cultivars are misused. Theoretical and practical issues involved in implementing strategies to delay pest adaptation to insecticidal cultivars are reviewed. Emphasis is placed on examining the "high dose"/refuge strategy that has become the goal of industry and regulatory authorities.