Potential for Entomopathogens to Delay Resistance to Bt Crops

Authors: GASSMANN,, A.J. - IOWA STATE UNIV.; STOCK,, S.P. - UNIV. OF ARIZONA; Sisterson, Mark; CARRIERE,, Y. - UNIV. OF ARIZONA; TABASHNIK,, B.E. - UNIV. OF ARIZONA

Submitted to: Entomology International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2008
Publication Date: 7/6/2008
Citation: Gassmann,, A., Stock,, S., Sisterson, M.S., Carriere,, Y., Tabashnik,, B. 2008. Potential for Entomopathogens to Delay Resistance to Bt Crops. Entomology International Congress, July 6-12, 2008, Durban, South Africa. Abstract Not Available.

Interpretive Summary:

Technical Abstract: The past decade has witnessed a continual increase in the use of crops genetically modified to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). This presents the challenge of designing agricultural systems to manage pests and the evolution of resistance to Bt. Currently, the refuge strategy is used in the United States and elsewhere to manage pest resistance, and requires planting of a non-Bt host plant near a Bt crop. We tested whether entomopathogenic nematodes might act synergistically with Bt crops by killing pests in non-Bt refuges and by increasing the fitness cost of Bt resistance. Fitness costs occur when, in the absence of Bt toxin, resistant insects are less fit than susceptible insects. We report that entomopathogenic nematodes increase the fitness cost of Bt resistance, indicating that their presence in refuges may delay resistance of pest to Bt; a conclusion that is further supported by the results of simulation modeling. Our work points to the value of developing integrated pest management strategies for Bt crops that include entomopathogenic nematodes to manage pests in non-Bt refuges.