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Ontario Grain Farmer Magazine

Advancing management of corn rootworm in Ontario

Principal Investigator: Jocelyn Smith

Research Institution: University of Guelph

Timeline: April 2023 – March 2026  

Objectives:

  • Evaluate the efficacy, establishment, and persistence of entomopathogenic nematodes for control of Bt-susceptible and Bt-resistant corn rootworm in Ontario.
  • Economic analysis of the impact of corn rootworm (CRW) management strategies.

Impacts:

  • Diversification of integrated pest management (IPM) strategies for CRW management will enable longer-term use of Bt-CRW technology and reduce the potential for increased insecticide use associated with Bt-CRW resistance.
  • Development of a comprehensive IPM plan for CRW. incorporating entomopathogenic nematodes for biological control services. This will minimize costly insecticide use, reduce negative environmental impacts, and provide ongoing sustainable suppression of CRW populations.
  • As few insecticide options are available or anticipated in the future for CRW management, the impact of biological control agents and their conservation will become increasingly important. Pest management using biological control will increase agroecosystem resiliency in an economical manner.
  • Determination of the economic impact associated with CRW injury and management strategies will help Ontario corn producers make informed, responsible, and sustainable production decisions.
  • Training highly qualified personnel in IPM and agronomy, such as the summer and MSc students in this project, will provide valuable human resources within the Ontario agricultural industry.

Scientific Summary:

Corn rootworm (CRW) is one of the most damaging insect pests of corn. In Ontario, CRW is managed using rotation with non-host crops; however, there are a significant number of acres where continuous corn is grown for livestock feed or by cash crop growers. Commercialization of Bt-corn for CRW in 2003 provided an elegant management solution, reducing insecticide use among corn producers. However, resistance to CRW Bt-corn was first observed in 2009 in the US and has become widespread throughout the Corn Belt and to all CRW Bt proteins. Since 2012, isolated strains of Bt-tolerant CRW have been identified in Ontario; however, increasingly, CRW Bt-corn failures are being reported since 2019. This emerging problem puts corn producers at risk of losing efficacy of CRW Bt-corn technology. Other than crop rotation and Bt-corn, Ontario corn producers only have soil insecticide application as a CRW management option, which requires costly planter modifications. Furthermore, increasing reliance on insecticides may lead to resistance and have negative impacts on non-targets.

Application of entomopathogenic nematodes (EPNs) have been shown to reduce CRW root injury and emergence, even with Bt-resistant populations. This work, led by Dr. Elson Shields at Cornell University, has demonstrated that native EPNs isolated from soils in New York (NY) are more persistent and effective than commercially available nematode strains. This method is cost-effective and simple to implement as a supplemental CRW management tool. We hypothesize that EPNs produced in NY will be as effective and persistent in Ontario soils due to similar climatic conditions and agronomic practices. This project will investigate EPN efficacy under different agronomic practices, in combination with various Bt-CRW traits, and will enable on-farm testing. Lastly, we wish to conduct a comprehensive economic analysis of CRW management strategies in Ontario to determine the partial profitability associated with various CRW management approaches.

External Funding Partners:

The project was funded in part by the Ontario Agri-Food Innovation Alliance, a collaboration between the Government of Ontario and the University of Guelph.

Bayer CropScience Canada

CropLife Canada

MITACS

Corteva AgriSciences