Effects of refuges on the evolution of resistance to transgenic corn by the western corn rootworm, Diabrotica virgifera virgifera LeConte

Authors

Jennifer Deitloff, Iowa State University; Lock Haven University
Mike W. Dunbar, Iowa State University
David A. Ingber, Iowa State University
Bruce E. Hibbard, USDA-ARS, University of MissouriFollow
Aaron J. Gassmann, Iowa State University

Document Type

Article

Date of this Version

2015

Citation

Pest Manag Sci, 2015

Comments

U.S. Government work

Abstract

BACKGROUND: Diabrotica virgifera virgifera LeConte is a major pest of corn and causes over a billion dollars of economic loss annually through yield reductions and management costs. Corn producing toxins derived from Bacillus thuringiensis (Bt) has been developed to help manageD. v. virgifera.However, previous studies have demonstrated the ability of this species to evolve resistance to Bt toxins in both laboratory and field settings.

RESULTS: We used an experimental evolution approach to test the refuge strategies for delaying resistance of D. v. virgifera to corn producing Bt toxin Cry34/35Ab1. In the absence of refuges, D. v. virgifera developed resistance to Bt corn after three generations of selection. In some cases, non-Bt refuges reduced the level of resistance compared with the strain selected in the absence of refuges, but refuge strains did show reduced susceptibility to Bt corn compared with the unselected strain.

CONCLUSIONS: In this study, non-Bt refuges delayed resistance to Bt corn by D. v. virgifera in some cases but not others. Combining the refuge strategy with pyramids of multiple Bt toxins and applying other pest management strategies will likely be necessary to delay resistance of D. v. virgifera to Bt corn.