Clubroot disease is not only spreading, but also adapting in real-time, as the number of confirmed versions of the soilborne disease that reduces canola yields in Western Canada has climbed to 55 as of this winter.
“The growing season in 2024 was quite good for the clubroot disease itself. There were quite a few new cases… we’re still seeing a proliferation or diversification of pathotypes,” explains Dr. Stephen Strelkov, plant pathologist at the University of Alberta, in this new Canola School episode recorded at the 2025 CropConnect Conference at Winnipeg, Man.
Many of these new pathotypes are rare, but he says surveillance is critical as new versions can overcome genetic resistance in commercial canola varieties.
Pathotypes known as 3A and 3D, along with 3H, are the most prevalent, accounting for about 60 per cent of cases, he notes.
But he recommends keeping a close eye on a few variants of pathotype 9, specifically 9D and 9E, which are not widespread, but can be highly virulent and break resistance in ways that 3A and 3D couldn’t. “They’re still quite restricted geographically, mainly between Edmonton and Calgary.”
First found in Alberta in 2003, it’s been more than 15 years since clubroot was also confirmed in Saskatchewan and Manitoba, but it remains largely an Alberta problem — over 90 per cent of confirmed cases to date are still in the province. While environmental and soil conditions are part of the equation, Strelkov says he believes the arrival of resistant varieties on the market before the disease became widespread in Saskatchewan and Manitoba is likely a major factor why growers in the two provinces have not seen an explosion in cases like Alberta.
Watch/listen to Dr. Strelkov discuss the newest clubroot findings from farmers’ fields and in the lab, including genomics research that could help with diagnosing pathotypes, in breeding resistant canola varieties, and with farmers figuring out which varieties to grow — recorded at CropConnect 2025:
Related: Saskatchewan updates clubroot distribution map
Subscribe: Apple Podcasts | Youtube Music | RSS | Subscribe to our Podcasts
