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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-BASED MANAGEMENT OF INSECT PESTS OF CORN, WITH EMPHASIS ON CORN BORERS, ROOTWORMS, AND CUTWORMS

Location: Corn Insects and Crop Genetics Research

Title: Susceptibility and aversion of Spodoptera frugiperda to Cry1F Bt maize and considerations for insect resistance management

Authors
item Binning, Rachel -
item Coats, Joel -
item Xiaoxiao, Kong -
item Hellmich, Richard

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2013
Publication Date: February 1, 2014
Citation: Binning, R., Coats, J., Xiaoxiao, K., Hellmich II, R.L. 2014. Susceptibility and aversion of Spodoptera frugiperda to Cry1F Bt maize and considerations for insect resistance management. Journal of Economic Entomology. 107(1):368-374.

Interpretive Summary: Genetically modified plants with resistance to insects are popular with growers because they protect yields and reduce insecticide use. Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis), where the high-dose/refuge strategy is used to control the development of insect resistance. Insect resistance management (IRM) plans for new geographies, however, may need to consider alternative strategies because some maize pests have low susceptibility to Bt toxins and do not satisfy high-dose criteria. Before implementing an IRM plan, it is useful to understand the biology and susceptibility of the primary pest(s) for each geography. Fall armyworm (Spodoptera frugiperda ) is an important pest of maize in Central and South America, but it has low susceptibility to some types of Bt maize. The behavioral and toxic response of fall armyworm to Cry1F maize was investigated by measuring the percentage of time naïve older larvae (third-instars) spent feeding during a three-minute exposure. Third instars also were exposed to Cry1F maize for 14 days to measure weight gain and survival. Fall armyworm larvae demonstrated an initial, post-ingestive aversive response to Cry1F maize, and very few larvae survived a 14 day exposure. The role of susceptibility and avoidance are discussed in the context of global IRM refuge strategy development for Bt products. This information is useful to all scientists interested in developing IRM plans to safeguard the Bt maize technology.

Technical Abstract: Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis Hubner). However, most Bt maize products also are cultivated outside of North America, where the primary pests are different and often have lower susceptibility to Bt toxins. As these Bt maize products are commercialized in new geographies, insect resistance management (IRM) plans for those geographies need to consider relevant pest and toxin combination, instead of assuming the high-dose refuge strategy applies to all pests in all geographies. Before implementing an IRM plan that includes size and placement of refuge, it is useful to understand the biology and susceptibility of the primary pest(s) for each geography. Fall armyworm (Spodoptera frugiperda J.E. Smith) is an important pest of maize in Central and South America. S. frugiperda susceptibility to Cry1F (expressed in event 1507) is an example of a pest-by-toxin interaction that does not meet the high-dose definition. The behavioral and toxic response of S. frugiperda to Cry1F maize was investigated by measuring the percentage of time naïve third-instars spent feeding during a three-minute exposure. S. frugiperda also were exposed as third-instars to Cry1F maize for 14 days to measure weight gain and survival. S. frugiperda demonstrated an initial, post-ingestive aversive response to Cry1F maize, and very few larvae survived a 14d exposure. The role of susceptibility and avoidance are discussed in the context of global IRM refuge strategy development for Bt products.

Last Modified: 9/21/2014
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