Stripe rust has been confirmed in the Ontario winter wheat crop. Ontario Ministry of Agriculture, Food and Agribusiness plant pathologist Albert Tenuta shared the news at the Ridgetown agribusiness breakfast meeting this week.
The disease can cause up to 50 per cent yield loss if not managed properly. It was confirmed after samples collected by Bayer Crop Science agronomist Leanne Freitag in fields at Mitchell, Perth County were analyzed at the the University of Guelph’s diagnostic lab.
According to Tenuta, unlike 2024 when the disease devastated fields in Mitchell and other areas like London and Plattsville, the symptoms of this stripe rust infection are not typical. In this instance, the stripe rust is being found in the lower leaves, which indicates that the disease likely overwintered as a result of fall infection in winter wheat planted last fall. The fields have been sprayed to control the disease.
With the amount of stripe rust present last year, early planting, lush growth and persistent snow cover, “the conditions were favourable for the potential or higher risk for overwintering,” says Tenuta.
Overall, Tenuta says that the potential for stripe rust infection in Ontario in 2025 is lower. He’s been talking with his colleagues in the U.S. who are seeing low incidence and severity of the disease this spring. That’s much different than 2024 when early infection and severity impacted the U.S. crop, and the disease, as predicted, moved north to significantly impact areas of Ontario.
Tenuta is telling growers to be vigilant about getting out and scouting their winter wheat crops. He notes that stripe rust continues to adapt and pathologists are seeing some of the races adapt to warmer temperatures. “In the past, we used to say 15 degrees Celsius was the cut off and and after that we would not worry about it. Now we’re pushing 18, maybe 20 degrees, and seeing it longer into the season with with stripe rust being a little more heat tolerant.” He adds that more heat tolerant races are starting to make up a greater percentage of the disease populations.
When growers identify stripe rust, Tenuta says they need to act immediately and apply a fungicide. “And the good thing is we have lots of products that are really good on it.”
Growers can click here for further management tips shared by OMAFA cereals specialist Joanna Follings.
