Canola field inspections reveal high volume of Clubroot

LEDUC COUNTY -- Eleven per cent of Leduc County's canola fields tested positive for Clubroot this year.

During the 2025 growing season, the County's Agricultural Services inspected 672 canola fields for the presence of the disease. Of the fields surveyed, 77 tested positive for the presence of clubroot, for a total of eleven per cent. Of these, 52 of the fields had been confirmed positive in the past, while the remaining 23 are fields that administration had not identified clubroot on prior to this year.

Clubroot is a disease that affects canola and other cruciferous plants, such as cabbage, mustard, and broccoli.  It is caused by 'Plasmodiophora brassicae', which is a pathogen that can remain in the soil for many years. The disease attacks the roots of the canola plant, causing the roots to become swollen and deformed.  Affected roots are also impeded from absorbing water and nutrients from the soil, causing the plant to starve. 

In 2007, Clubroot was declared a Pest under the Agricultural Pests Act.  Being declared a pest brought new responsibility on not only producers, but municipalities to take "active measures" to prevent or control the pest in Alberta.

When conducting the inspections in Leduc County, the severity of infestations was assessed using the Disease Severity Index. Of the 77 canola fields that were confirmed to have Clubroot, only one field had a DSI rating greater than 20.  A second, more thorough survey was conducted on this field, and a sample of the galls was taken and sent to the University of Alberta for pathotype testing.

Clubroot is difficult to completely eradicate, so management typically focuses on minimizing spread and prevention. Some of the most effective strategies include long crop rotations to reduce spore buildup and practicing rigid sanitation to prevent the movement of contaminated soil on equipment.