The Canola Council of Canada is reminding farmers to implement clubroot management strategies, including scouting fields for symptoms of the disease.

This after Manitoba Agriculture’s discovery of a clubroot pathotype in South Central Manitoba that is able to overcome the original source of clubroot resistance. Outside of Alberta, very few fields have been found to contain novel pathotypes like this, and this is the first finding in Manitoba. The discovery of pathotype 3A in the Rural Municipality of Pembina comes after multiple cases of clubroot DNA and plant symptoms having been found throughout the province of Manitoba since 2013.

“This is yet another cue for the industry to continue to take this disease seriously and implement clubroot management plans,” says Dan Orchard, agronomy specialist with the Canola Council of Canada. “We still have an opportunity to get ahead of this disease and limit the impact it has on canola producers and the industry.”

All canola producers are encouraged to grow clubroot resistant varieties, limit the movement of soil, extend rotations to at least a two-year break between canola crops, control canola volunteers and other brassica hosts, and diligently scout. Symptoms of the disease are most noticeable late in the season, and can still be seen during and after harvest on plant roots. Producers are strongly encouraged to familiarize themselves with clubroot symptoms and start scouting this fall.

“The development of clubroot and discovery of a pathotype that is virulent to the original source of clubroot resistance is concerning to Manitoba canola farmers,” says Ron Krahn, Manitoba Canola Growers Association director and chair of the Research Committee. “Clubroot is one of the latest challenges in canola production. We know how important canola is for a profitable crop rotation, which is why we feel the research dollars that MCGA spends every year on current production challenges is money well spent.”

The Canola Council is working with industry and academics through the Clubroot Steering Committee to ensure that clubroot resistant varieties are used effectively in a clubroot management plan. Even when implementing resistant varieties, growers need to carefully scout to ensure the resistance deployed is effective against the pathotypes in the field and determine whether new sources of resistance are necessary. Under high resting spore loads, symptoms can occur after using the same resistance source two or three times, or even sooner.

“It is critically important to limit the pressure we put on resistance by using resistant varieties before spore concentrations are high, extending the break between canola crops and changing up resistance sources if necessary,” says Orchard.