​​Bt Resistance and Implications for Future Pest Management Strategies

February 2020 | 29 min., 50 sec.
by David Kerns
Texas A&M AgriLife Extension

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​Over the past few years, cotton and corn growers and consultants have reported increasing incidences of Helicoverpa zea (bollworms/earworms) successfully feeding and causing injury to Bt cotton and corn. Since 2015, we have been conducting surveys across the southern United States of H. zea for resistance to key Bt toxins: Cry1Ac, Cry1F, Cry2Ab2, and Vip3A. Resistance to Cry1Ac and Cry1F appears to be near ubiquitous, and resistance to Cry2Ab2 is common and widespread. Resistance to Cry2Ab2 appears to be controlled by a partially recessive gene. Thus far, resistance to Vip3A is very low, but there have been incidences of H. zea feeding on and injuring corn and cotton expressing Vip3A. Because of Bt resistance issues, cotton growers have had to commonly utilize insecticides in dual-gene cotton. Among insecticides, those containing chlorantraniliprole (Prevathon and Besiege) offer the longest-lasting control.

About the Presenter

David KernsDavid Kerns is a Professor in the Department of Entomology at Texas A&M University. He has an administrative role, serving as the Associate Department Head and Statewide IPM Coordinator; and a research/extension role focusing on developing IPM program​s in row crops including cotton, corn, grain sorghum and soybean. David received his B.S. degree in entomology from Texas A&M University, a MS in entomology from Oklahoma State University and a PhD in entomology from Auburn University.​

Contact Information:
Email: dlkerns@tamu.edu


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