With findings of clubroot disease in parts of Western Canada where it has not been a problem before, at what point should a farmer in these new clubroot areas switch to growing clubroot-resistant canola varieties?
To make that decision, you must first assess and prioritize the risks to your canola, suggests Anastasia Kubinec, oilseed specialist with Manitoba Agriculture, in this Canola School episode.
Before doing anything else, she recommends getting your soil tested to determine whether you have clubroot or not. From there, a grower can determine which variety is the best fit.
“The clubroot trait is a very good trait, but it’s one of many traits you can get in your variety. We feel in Manitoba, with such low levels of clubroot, but very high incidence of blackleg, that maybe blackleg traits could be rated higher than clubroot,” she explains, noting maturity, yield potential, pod-shatter tolerance and special oil attributes could also be factors in choosing a variety.
With breakdown of resistance already evident among clubroot-resistant varieties in Alberta, Kubinec says soil test results can also help a grower manage against potentially losing the effectiveness of the trait. If the pathogen is not present, there won’t be any selection pressure, she explains: “But if there are low or medium levels and the farmer doesn’t know that, and he’s in a canola-wheat-canola-wheat rotation always using the clubroot-resistant varieties, chances are it could build and he could have selection pressure for the new races that are out there.”
Check out this Canola School episode filmed at the recent CanoLab workshop in Brandon for more on when to grow a clubroot-resistant variety: