Clubroot is the most devastating soil-borne disease of canola because it is hard to detect until serious losses occur, is impossible to eradicate, and can last 10-20 years in a field.
The disease continues its march across western provinces, and more recently has been found in Ontario (Field Crop News).
In addition to field scouting, soil testing in the fall is the best way to help manage. It can serve two objectives; detect the presence of clubroot in a field, and quantify the level of spores throughout a field. Soil testing will allow growers to be proactive in developing a sanitation plan to control the spread of spores by equipment.
For more information, consult How to Test Soils for Clubroot pathogen (Canola Watch).