Synergy between Cry and Vip3 toxins targeting lepidopteran pests: prevalence and potential implications for management of resistance to pyramided Bt crops.

Authors

Yves Carrière, Benjamin A Degain, Heba Abdelgaffar, Dawson Kerns, Juan Luis Jurat-Fuentes, Bruce E Tabashnik

Published in

Journal of economic entomology. Aug 07, 2026. Epub Aug 07, 2026.

Abstract

Pyramided crops producing Cry and Vip3Aa toxins from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) play a central role in managing lepidopteran pests in the United States, in part because the major corn and cotton pest Helicoverpa zea Boddie (Lepidoptera: Noctuidea) has evolved practical resistance to all lepidopteran-active Cry toxins produced in transgenic crops. Although several factors affect the evolution of resistance to pyramided crops, the implications of synergy between Cry and Vip3Aa toxins for managing resistance have rarely been considered. Here, we analyzed data from the literature and new data from diet-overlay bioassays of 2 related strains of H. zea susceptible (GA-RS) or resistant (GA-R13) to Cry1Ac and Vip3Aa to evaluate interactions between Cry and Vip3 toxins. Our analysis of 258 cases evaluating interactions between Cry and Vip3 toxins from 16 studies based on artificial-diet bioassays of 18 species of lepidopteran pests shows that synergy occurs more frequently (42.7%) than independent (34.7%) or antagonistic (22.6%) interactions. Our analysis of data from 4 studies of 4 species of lepidopteran pests shows that synergy between Cry1Ab and Vip3Aa typically occurs for pyramided Cry1Ab + Vip3Aa corn. The level of synergy between Cry1Ac and Vip3Aa in diet bioassays was similar for GA-RS and GA-R13, demonstrating that the evolution of resistance to these toxins did not affect synergy. We discuss how considering synergy between Cry and Vip3Aa toxins could improve the monitoring of Vip3Aa resistance in H. zea with sentinel plots and the development of more realistic models to forecast the evolution of resistance to pyramided Bt crops.

PMID:
42567834
Bibliographic data and abstract were imported from PubMed on 08 Aug 2026.

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