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ViewAttendees 1

10-Minute Paper

Plant-Insect Ecosystems

P-IE: IPM - Field Crops 1

Multiple Bt resistance in European corn borer Ostrinia nubilalis (Lepidoptera: Crambidae) in Canada

Wednesday, November 8, 2023
9:00 AM – 9:12 AM ET
Location: Gaylord National Resort & Convention Center, Maryland 5-6
In-Person

    Presenting Author(s)

  • Jocelyn L. Smith

    Research Scientist
    University of Guelph
    Ridgetown, Ontario, Canada

    • Co-Author(s)

  • Yasmine Farhan

    Research Associate
    University of Guelph
    Ridgetown, Ontario, Canada

The first case of field-evolved resistance in European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) to transgenic corn (Zea mays) producing a Bacillus thuringiensis toxin was discovered in Nova Scotia, Canada in 2018. This case involved resistance to Bt corn producing Cry1Fa toxin. Since 2018, O. nubilalis were collected in several corn-growing regions of Canada to test their progeny for susceptibility to four Bt toxins produced by currently available Bt corn: Cry1Fa, Cry1Ab, Cry1A.105, and Cry2Ab. Based on toxin concentrations killing 50% of larvae from 23 field-derived strains relative to two susceptible laboratory strains, the resistance ratio was at least 10 for Cry1Fa for 12 strains (52% of strains) consisting of 10 strains from Nova Scotia, as well as strains from near Montreal, Quebec and Roseisle, Manitoba. We found low but statistically significant resistance relative to at least one of two susceptible strains for Cry1Ab (23% of strains), Cry1A.105 (45% of strains), and Cry2Ab (14% of strains), with maximum resistance ratios of 3.9, 5.8, and 2.0, respectively. These results provide key information for addressing O. nubilalis resistance to Bt corn in Canada.