Toward a strategy for reducing the spore density and dissemination of clubroot of canola in Alberta

The Challenge

With clubroot continuing its spread across Alberta, the use of resistant cultivars is increasing. Repeated cultivation of resistant cultivars in fields with well established infections increases the risk of resistance breakdown and the development of new strains.

The Project

Fully assess soil resting spore populations from the impact of cropping clubroot resistant canola cultivars in addition to monitoring the spread of the pathogen. Technical feasibility of fumigation will also be investigated for small-patch management.

The Results

4-year resistance rotation sequences resulted in lower gall formation in susceptible canola grown subsequently. Fumigation ‘Vapam’ was effective at 400-800 L/ha but is required to be sealed with plastic for 12 days. At the end of 2017, the grand total of confirmed cases of clubroot across 36 counties in Alberta is 2744 fields (compared to 1064 fields in 2013).

Grower Benefits

Increased knowledge on the importance of clubroot resistance stewardship and the spread of the pathogen across Alberta. Repeated cultivation of resistant cultivars should be avoided to prevent selection for clubroot resistance breakdown in commercial canola varieties. Fumigation can be used for small patch management, but it is expensive and requires extensive training.