By Jana Rumpel, Crop Lab and Field Technician and Alireza Akhavan, PhD, AAg, Provincial Plant Disease Specialist, Crops and Irrigation Branch, Regina
July 2024
Clubroot is a soil-borne disease of brassicaceous plants and can be challenging to control if well established in a field or region. If there are no management techniques applied to farming practices, clubroot can continue to negatively impact crops. Effects include, but are not limited to, reduced yields, wilting and sometimes even premature plant death. This happens because the pathogen causes deformed, swollen roots (galls) which restrict the plant’s ability to obtain water and nutrients from the soil. The following are some options to consider for managing clubroot:
Weather conditions:
- To prevent the spread of clubroot, avoid driving on fields in farm equipment or other vehicles during wet conditions. Not only is clubroot most active in wet conditions, but soil more readily adheres to equipment when it is wet.
Minimize soil movement:
- Soil disturbance caused by tillage will often result in soil from the A horizon (or topsoil) coming to the surface. This makes it easier for the spores to spread by wind, runoff and other natural factors.
- Soil conservation practices such as direct seeding reduces soil movement by equipment, wind, or water erosion, reducing the potential of clubroot spread.
Crop rotation:
- It is best to have a minimum of a three-year crop rotation between growing canola (and other brassicaceous crops that host clubroot) with non-host crops. This reduces the buildup of clubroot spores in the soil and minimizes the risk of severe outbreaks.
- A two-years break is typically enough time for a significant number of clubroot spores to become inactive. However, the time frame does depend on the amount of spores present. A two-year break from canola is also needed for efficient management of other important canola diseases such as blackleg, verticillium stripe and sclerotinia stem rot.
- It is important to note that clubroot spores survive livestock digestive systems. Seeding affected areas to grass for grazing purposes can still spread the pathogen.
Resistant cultivars:
- Using clubroot resistant varieties for all canola fields is a good management technique to reduce the pathogen and risk of clubroot occurring.
Biosecurity:
- It is vital that people in the agriculture industry follow biosecurity protocols and do their part in trying to control clubroot and other soil born pests including other high-impact pathogens, weeds and insect pests through biosecurity.
- Disinfect equipment and other things that are used for farming which touch soil.
- Create a biosecurity plan and make anyone who enters your land aware of it.
- You can review this recent article to learn more on the importance of biosecurity in the management of clubroot.
Monitoring:
- By frequently monitoring and scouting your crops you are more likely to notice you have clubroot early. The sooner you are aware that there is clubroot present, the sooner you can manage it and prevent its spread.
To learn more about clubroot visit our Clubroot of Canola webpage on the disease or the Canola Council of Canada website.