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Mitigation and management of Cry1F resistance in European corn borer in Canada

Principal Investigators: Rebecca Hallett and Jocelyn Smith

Research Institution: University of Guelph

Timeline: July 2020 – July 2025  


  • Determine the phenology of European corn borer (ECB) in Canadian corn producing regions at high-risk of resistance development to transgenic corn:
    • Determine the timing, duration, and peak flight of ECB moths, and voltinism in different corn-growing regions in Canada.
    • Validate models for ECB development in different corn-growing regions in Canada.
    • Determine the pheromone race and host range of ECB in different corn-growing regions in Canada.
  • Determine the distribution of Cry1F-resistant ECB populations in Canadian corn producing regions and the susceptibility of ECB to other Bt proteins:
    • Determine the distribution of Cry1F-resistant ECB in Canada before, during, and after implementation of mitigation strategies such as removal of single-trait Bt products from the region and replacement with pyramided Bt hybrids.
    • Determine the susceptibility of ECB populations in Canadian corn growing regions to other Bt proteins (Cry1Ab, Cry1A.105, Cry2Ab2).
  • Characterize Cry1F resistance in ECB populations in Eastern Canada:
    • Validate small nucleotide polymorphism (SNP) markers for Cry1F resistance using NS Cry1F-resistant populations.
    • Determine the frequency of Cry1F resistance in ECB in Canada using SNP markers before, during, and after mitigation strategy implementation.
    • Determine the heritability of Cry1F resistance from field-derived Cry1F resistant populations.
    • Develop life tables for Cry1F-resistant and susceptible ECB populations in Canada to determine whether fitness costs are associated with Cry1F resistance.
    • Determine potential gene flow between Canadian ECB populations.
  • Optimize Cry1F resistance monitoring techniques:
    • Compare the cost and efficacy of Cry1F resistance monitoring between traditional diet-overlay concentration-response bioassay method and new molecular method.        


  • Understanding the current extent of Cry1F resistance in Canada will inform integrated pest management and insect resistance management strategies for corn growing regions in Canada.
  • ECB collections made across Canada will be evaluated for their susceptibility to Cry1F and remaining Bt proteins which will provide critical information to develop best management and management (IRM) practices nationwide.
  • A comprehensive integrated pest management plan for ECB in Canada will benefit Canadian corn producers and consumers by protecting the longevity of transgenic and insecticide technology, minimizing costly and unnecessary pesticide use, and reducing negative environmental impacts.

Scientific Summary:

            European corn borer Ostrinia nubilalis (Lepidoptera: Crambidae) (ECB) is one of the most serious insect pests of corn Zea mays (L.) in North America, causing yield and quality loss in corn grown for human consumption (sweet corn), livestock feed (grain and forage corn), and biofuel (ethanol production) as well as in many vegetable crops. In 1996, transgenic corn expressing insecticidal proteins from Bacillus thuringiensis (Bt corn) targeting ECB was commercialized, reducing management costs and yield losses across North America, and benefitting conventional and organic corn and vegetable producers due to area wide suppression of ECB. In 2018, our research team discovered the first case of field-evolved resistance to Bt corn in North America within ECB in Nova Scotia, Canada (Smith et al., 2019). The reaction to this discovery will be precedent-setting as unsuccessful mitigation of this situation jeopardizes ECB management in North America.

          The principal objective of the proposed research is to mitigate Cry1F resistance in ECB in Canada. To achieve this, it is critical to understand the phenology of ECB in Eastern Canada, characterize the Cry1F resistance discovered in Nova Scotia, determine the current distribution of Cry1F-resistant populations in Canada, and the susceptibility of ECB in Canada to remaining Bt proteins (Cry1Ab, Cry1A.105, and Cry2Ab2) for sustainable management. This situation also provides an opportunity to evaluate the strategy to mitigate Cry1F resistance by replacing single event Bt corn hybrids with pyramided products. Lastly, this occurrence provides an opportunity to evaluate the efficacy of current IRM strategies for Bt corn and investigate ways to improve resistance monitoring using molecular techniques. As the partner organizations supporting this project are major stakeholders and key communicators within the Canadian agricultural industry connected to corn pest management, the results of this project will be extensively disseminated, implemented, and impactful.

External Funding Partners:

NSERC Alliance




Manitoba Corn Growers Association


Atlantic Grains Council

Perennia Food and Agriculture Inc.

Manitoba Agriculture

Centre de réchérche sur les grains (CEROM)