Viable Clubroot Spores Found in Manitoba Soil


It was only a matter of time before clubroot infection or viable clubroot spores were found in Manitoba soil, still it’s not welcome news.

Manitoba’s provincial ag department released this press release today, underscoring the importance of spread prevention (Click here for a Canola School on the topic):


Manitoba Agriculture, Food and Rural Initiatives (MAFRI) is strongly encouraging farmers to follow best management and disease-prevention practices prior to seeding their 2013 canola crop.

Proper equipment sanitization, especially removal of soil from field equipment, is the most important factor for preventing the spread of soil-borne disease.  The use of disease-resistant varieties when growing canola, proper crop rotation and good weed management of alternate hosts will decrease the likelihood of a soil-borne disease infesting a field.  These practices will also help prevent heavier infestations from developing within a field where a disease may already be present at undetected levels.

In the 2012 canola disease survey, no clubroot disease symptoms were seen in any of the canola fields surveyed across Manitoba.  However, soil samples taken from six unrelated fields have been confirmed through polymerase chain reaction (PCR) analysis to contain clubroot DNA.  Further tests done under ideal greenhouse conditions indicate that two of the six soil samples produced weak clubroot gall symptoms on highly susceptible plants.  These test results are considered positive cases of clubroot, with viable spores able to produce disease.  Positive results in the PCR test only are considered ‘non-symptomatic fields of concern’.  In 2011, two soil samples were identified as non-symptomatic fields of concern, but retesting in spring 2012 resulted in negative PCR results.  All fields previously identified will be monitored, with additional soil samples tested in 2013.

Since 2009, 566 canola crops have been surveyed and 321 soil samples have been analyzed for clubroot DNA.  MAFRI, Agriculture and Agri-Food Canada, and the Canola Council of Canada will continue the Canola Disease Survey in 2013, surveying both in-field for canola diseases and collecting soil samples for clubroot DNA analysis.  The cost of testing soil samples for clubroot DNA is funded by the Manitoba Canola Growers Association, with support from the AAFC Clubroot Risk Mitigation Initiative. 

More information is available online at or by contacting MAFRI’s Crops Knowledge Centre at 204-745-5630

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