Why be concerned about the Bt resistant rootworm populations showing up in Ontario? Dr. Jocelyn Smith, University of Guelph Ridgetown Campus stands in a field that has cross resistant rootworm. The grower experienced more than 50% yield loss in this 2nd year silage corn field planted with a pyramid hybrid in 2020. Jocelyn discusses the […]
In fields where Bt rootworm corn hybrids have been used for more than three consecutive years, resistance among corn rootworm populations is suspected. Growers can no longer rely solely on Bt hybrids for protection against rootworm injury. The best management practice to reduce the resistant rootworm population is to rotate out of corn for at […]
Extensive injury by corn rootworm (CRW) to pyramid Bt rootworm (Bt-RW) hybrids was observed in several Ontario counties in 2020, suggesting that CRW populations have developed resistance to multiple Bt-RW proteins. The Canadian Corn Pest Coalition (CCPC) and OMAFRA have developed mitigation recommendations for continuous corn producers, in hopes of knocking back the resistant corn […]
Scouting for corn rootworm injury is important to detect potential resistance to rootworm Bt traits and to plan management options for the next growing season. It is especially important to report any fields showing signs of suspected resistance to your corn agronomist and the provincial entomologist. Rootworm larvae feed below ground on corn roots from […]