Western bean cutworm (WBC) is the most important corn pest in Ontario and lack of control can reduce grain yield and quality due to insect feeding and mycotoxin contamination. Unlike other primary corn pests, WBC are not controlled by most transgenic corn expressing Bt proteins. Monsanto has developed new insecticidal proteins to which WBC are susceptible according to preliminary research. To support long-term use of these promising management tools, this project aims to generate information necessary to develop an insect resistance management (IRM) plan. Life history parameters for WBC with and without exposure to these proteins will be determined using standard and novel bioassay techniques. Novel bioassay techniques using relevant corn tissues typically encountered by key WBC life stages in the field will be used to determine WBC susceptibility to realistic plant expression levels. Field experiments will be conducted to determine the efficacy of new proteins against WBC in Ontario and the optimal transgenic events for expression in commercial corn hybrids. Lastly, field experiments will be conducted to evaluate the efficacy and durability of proposed IRM strategies for new insecticidal proteins. The ultimate goal of this research is to investigate new, durable management options for WBC in Ontario.