The recent discovery of a clubroot-infested field in northwest Saskatchewan and the continued expansion of clubroot in Alberta should encourage all canola growers in Western Canada to scout fields for the disease.
“Dig up plants in all areas that show premature ripening and check a few random plants at each field entrance looking for galls on the roots,” says Curtis Rempel, vice president, crop production and innovation for the Canola Council of Canada. “With early detection of the disease, the grower can implement measures to keep clubroot below yield-reducing levels for the long term and keep it from spreading across the whole farm.”
Before or during swathing is the best time to scout because diseased patches are most obvious and galls, if present, will be at their largest.
“Severely-infected roots can’t transport adequate water and nutrients to above-ground plant tissues, which leads to stunted growth and premature yellowing. But keep in mind that spore-producing galls can be present even without obvious above-ground symptoms,” Rempel says. “That’s why digging up random plants, especially at field entrances, is an important step in early detection.”
Harvest is when lots of equipment is moved around, so preventing the movement of machinery into and out of a clubroot-infested field could save a grower a lot of time and effort in spring and future growing seasons. Taking a few minutes to scrape and sweep dirt off machinery used in an infested field, asking custom applicators to clean equipment before using it in your field, reducing your tillage usage post-harvest and working in least infected fields first and most infected fields last, where possible, can make a big impact on the prevention of spore movement in your fields.
Clubroot is a soil-borne disease and it spreads with the movement of spore-infested soil. It often shows up first at field entrances where equipment carrying infested soil – on openers, for example – makes first contact.
For growers whose canola is already swathed or is fully ripened, scouting is still possible. Root galls may have decayed, with typical whitish galls no longer present, but DNA tests of decayed galls can confirm the disease. Another option is soil analysis for the presence of clubroot DNA, which can be done at any time. For more on how to take soil and plant samples for DNA testing, go to clubroot.ca and read the “Identify Clubroot” section.
If clubroot is confirmed with the presence of galls or through DNA testing, clubroot can be contained with a two- to three-year break between canola crops on positive fields and by growing clubroot-resistant varieties on all acres in that farming operation. In non-canola years, pay special attention to controlling volunteer canola and other Brassica weeds (ex. wild mustard and stinkweed), which can harbour and increase the disease in non-canola years.
Source : Albertacanola