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Integrated pest management and insecticide resistance management for western bean cutworm in Ontario corn


Art Schaafsma & Jocelyn Smith


University of Guelph


OMAFRA – UofG Research Program; CFIA; Mitacs; DuPont; Syngenta; Dow AgroSciences


April 2017


March 2020


  • Adjust current action threshold recommendations for insecticidal control of western bean cutworm (WBC) in corn relative to mycotoxin accumulation.
  • Conduct field experiments to introduce alternative insecticide active ingredients alone, in combination, or in rotation for WBC control sufficient for mycotoxin management.
  • Maximize the effects of insecticidal toxins by understanding their distribution relative to exposure to critical stages of WBC in corn for the purpose of developing appropriate insect resistance management strategies and optimizing application technology.
  • Determine the baseline susceptibility of key larval stages of WBC to Vip3A and candidate insecticides alone and in combination.
  • Propose application and technology deployment strategies and an insecticide resistance management plan for WBC in corn.


  • A comprehensive insect resistance management plan for western bean cutworm (WBC) in Canada will benefit Canadian corn producers and consumers by protecting the longevity of transgenic technology, minimizing costly unnecessary pesticide use, and reducing negative environmental impacts.
  • The development of effective and long-term control of WBC will reduce the risk of grain quality loss in Ontario and serious negative effects on the health of livestock and human consumers, because when environmental conditions are favourable for Fusarium graminearum infection, even a very small amount of WBC damage can significantly increase DON accumulation in grain corn.


First identified in Ontario in 2008, western bean cutworm has become a significant economic pest of corn in Ontario. Western bean cutworm (WBC) continues to plague Ontario corn producers with losses mainly in grain quality due to insect damage-related moulds resulting in mycotoxin contamination. Fusarium graminearum infection which occurs frequently in Ontario results in increased contamination of grain with mycotoxins that have serious negative effects on the health of livestock and human consumers. The mycotoxin deoxynivalenol (DON), also known as vomitoxin or VOM, is probably the most important quality factor in trade of Ontario corn affecting both the livestock and ethanol industries. The distribution of WBC has significantly expanded from its native range in the western U.S. across the Midwest Corn Belt over the last few decades and recently into eastern Canada. There are three problems: one, the current published action threshold is yield-based and we have learned that it is not conservative enough because of the importance of mycotoxins; second, the transgenic solution we had hoped for in Cry1F has failed; and third, growers are depending mainly on one insecticide product (i.e. Coragen) to manage this pest.

The overall goal of this project is to develop a more reliable decision threshold to minimize insecticide use, the introduction of alternative active ingredients, and an insecticide resistance management (IRM) plan. A further benefit is that the seed industry will be introducing competitive hybrids carrying a new transgenic Bt protein (Vip3A) which our lab and field tests have shown to be highly effective against WBC. Again, reliance on this strategy alone will inevitably lead to the evolution of resistance. We propose to include the introduction of Vip3A in an IRM plan with the overall strategy of simultaneously extending the useful life of both the insecticides and the Vip3A trait. The overall benefit of this project will be development of a sustainable plan that will provide corn producers with a long term strategy for WBC management.

Project Related Publications:

Farhan, Y., Smith, J.L., Limay-Rios, V., and A.W. Schaafsma. 2020. The effect of simulated Lepidopteran ear feeding injury on mycotoxin accumulation in grain corn, Zea mays L. Journal of Economic Entomology. 113(5): 2197-2212.

Farhan, Y., Limay-Rios, V., Schaafsma, A.W., and J.L. Smith. 2022. Susceptibility and field exposure of Striacosta albicosta (Lepidoptera: Noctuidae) eggs and larvae in Ontario, Canada to four insecticides. Pest Management Science. 78(8): 3551-3563.