Clubroot (Plasmodiophora brassicae) is a serious soil-borne crop disease that affects canola and other cruciferous crops. It causes the formation of galls on the roots blocking essential nutrients and moisture, which leads to premature death of the plant. Clubroot was first confirmed in Alberta in 2003 when it was found in a canola field NW of Edmonton, and it was declared a regulated pest under the Alberta Agricultural Pests Act in 2007. A critical step in managing Clubroot is early detection therefore the Kneehill County Agricultural Services staff survey canola fields in the County for Clubroot on an annual basis, and encourage all canola growers to scout their fields as well. Symptoms of Clubroot in canola may present as root galls, premature ripening, wilting of the plant, and stunted growth. Clubroot is commonly found in the entrances to fields, but it can occur in any portion of a field.
Kneehill County now has two additional cases of Clubroot confirmed through the 2020 growing season bringing the total active cases up to four. There is one case in each of the following townships: 34-23, 32-23, 30-23, 33-26. Of the 2020 cases, one was identified and confirmed through the Kneehill County Agriculture Services annual canola surveys and another was identified by a producer during swathing and confirmed by Agriculture Services staff. When a case has been confirmed a notice is placed on the quarter section by the Kneehill County Pest inspectors as required under the Alberta Pest Act. Kneehill County staff then work with the landowner and/or occupant to create an acceptable management strategy including, as outlined in the Kneehill County Policy 1-29-3 Agricultural Pests – Clubroot Control, no growing of any crucifer crops for a period of 3 years after which only a Canadian Food Inspection Agency approved Clubroot resistant crop variety may be planted.
Clubroot is spread through the movement of soil containing Clubroot spores, typically transported on equipment and vehicles, but can also be moved by wildlife and soil erosion by wind and water. Clubroot spores have a half-life of approximately 4 years, however, trace spores have been shown to survive up to 20 years in soil. For this reason, the number one best way to prevent and manage Clubroot is to diversify and expand crop rotations to 3 or more years between canola crops. There is currently no direct treatment for this disease but it can be effectively managed to reduce the severity of its impact on crop yield. Best management practices for the prevention and management of Clubroot include:
- appropriate crop rotation of 3 or more years between canola crops
- regular field scouting
- seeding Clubroot-resistant canola varieties and selecting different brands and varieties each time to utilize a full range of resistance
- knocking-off dirt, washing, and sanitizing equipment before and after accessing cropland whenever possible
If you require more information, please contact Kneehill County Agricultural Services at 403-443-5541.
Additional information on Clubroot:
- Alberta Agriculture & Forestry Map of Clubroot in Alberta
- Alberta Agriculture & Forestry Clubroot Disease of Canola and Mustard (Pictures of Roots)
- Alberta Agriculture & Forestry Clubroot Management Plan
- Canola Council Brochure – All About Clubroot
- Canola Council Brochure – Equipment Sanitation Guide
- Canola Council Clubroot Information