Skip to content
Grain Farmers of Ontario is the province’s largest commodity organization,
representing Ontario’s 28,000 barley, corn, oat, soybean and wheat farmers.
Search
Ontario Grain Farmer Magazine

Sustainable management of cereal leaf beetle in southern Ontario wheat

Principal Investigator: Lauren Des Marteaux and Haley Catton

Research Institution: Agriculture and Agri-Food Canada

Timeline: April 2024 – March 2027   

Objectives:

  • Determine cereal leaf beetle (CLB) parasitism rates by the wasp Tetrastichus julis in relation to CLB larval stage and abundance, and agronomic factors in winter wheat and spring wheat in Ontario.
  • Determine seasonal timing & abundance of CLB larvae specific to Ontario in relation to plant stage and agronomic factors (model validation).
  • Detect and identify parasitism of CLB larvae by species other than T. julis in Ontario.
  • Identify winter wheat varieties that are reliably resistant to CLB in Ontario.
  • Quantify the impact of CLB feeding damage on wheat yield.

Impacts:

  • CLB management via wheat resistance and natural enemies will reduce reliance on pesticides, benefitting farmers, consumers, and the environment by reduced CO2 emissions and costs.
  • A validated southern Ontario CLB timing model will optimize scouting efforts for the damaging life stages of the insect.
  • CLB parasitoid surveys will inform new practices in wheat IPM by:

 – Guiding decisions on whether or not to spray insecticide for CLB.

 – Identifying if and where field insectaries for parasitoids may be needed.

 – Potentially changing tillage practices in fields with parasitoids.

  • Ontario farmers (especially those in areas with high CLB pressure and/or low CLB natural enemies) will benefit immediately by gaining a list of reliably CLB-resistant wheat lines and in the long term from future wheat lines that are bred for improved CLB resistance.
  • A better understanding of the CLB damage-yield loss relationship can help to refine insecticide action thresholds in wheat.

Scientific Summary:

Cereal leaf beetle (CLB) is an invasive pest of wheat and other cereals (including barley, rye, oats, and corn) that has become established across Canada. Larval feeding is the most destructive to crops, and yield losses as high as 80% have been reported for winter wheat when CLB populations are not controlled. Ontario has seen a recent resurgence of CLB in winter and spring cereals, and climate change is expected to further increase the range and severity of CLB infestations in Canada. Foliar insecticides are currently the main management strategy for CLB in Ontario, but this is at odds with demands to reduce agricultural carbon emissions. Insecticides also harm natural enemies of CLB (and other pests), and their consistent use can lead to insecticide resistance. Alternative, environmentally sustainable CLB management tools are therefore needed.

We propose two complementary strategies to reduce the impact of CLB in cereals: 1) bolstering of natural enemies and 2) development of CLB-resistant wheat varieties. The parasitoid wasp Tetrastichus julis is an effective biocontrol agent, and although CLB parasitism by T. julis in Ontario was high (up to 95%) in the 1970s, parasitism rates are currently patchy (0-52%). Potentially, T. julis populations have crashed and need re-establishment. Recently we found two additional CLB parasitoid wasp species in Ontario. We will conduct surveys across Ontario to learn the current status of T. julis and other, potentially novel CLB parasitoids. Some winter wheat varieties resist CLB infestation and damage (e.g., by later heading and high leaf trichome density and waxiness). However, relative CLB resistance information is lacking for most Canadian winter wheat varieties, and the relationship between CLB feeding pressure and yield loss varies considerably between years. We will conduct multi-year, multi-location screening to identify CLB-resistant wheat varieties and understand the quantitative relationship between feeding damage and yield loss.

External Funding Partners:

This project was funded in part by the Government of Canada under the Sustainable Canadian Agricultural Partnership’s AgriScience Program.