New Pathotype of Clubroot found in Manitoba – Raising need for more biosecurity
There was a time when new weeds appeared in your crop, you went to the Ag Rep at the Manitoba Agriculture office, and asked him or her to identify it and what spray to use. Yes, I know that is simplistic, and sometimes farmers would take the plant to the local coffee shop or elevator agent to help identify the new weed on the block.
With diseases in livestock, calf scours, mastitis in milk cows, and most recently, PED virus in pigs in Manitoba, and African Swine Fever breaking out all over the world, the word biosecurity comes up regularly.
While not a livestock disease per se, biosecurity is a word that fits this new weed discovered in a canola field in south-central Manitoba.
Manitoba Agriculture has identified a new strain of clubroot of canola (Plasmodiophora brassicae), in the Rural Municipality of Pembina.
“Clubroot is a disease of canola and other brassica species that inhibits the function of plant roots to take up water and nutrients from the soil. Infected plants suffer premature ripening, significantly reduce yield and early plant death under moderate to severe levels of infestation,” said the release. “Clubroot is a soil-borne disease and can be transferred from field to field on soil particles. Soil movement can be on footwear, vehicle tires, farm machinery, custom equipment, or via wind or water movement across a landscape. The new strain of clubroot is identified as pathotype 3A, using the combined designation of the Canadian Clubroot Differential Set (2018) and the Williams set (1966). Pathotype 3A can overcome some first-generation sources of genetic resistance in commercial canola cultivars. Traditionally rated “resistant” or “R” canola varieties will not be effective in preventing clubroot infection against this pathotype strain.”
Long-term sustainability of canola production requires active crop rotation and rotation of sources of genetic resistance, together with good farm biosecurity to suppress clubroot infection.
Dan Orchard, the agronomy specialist with the Canola Council of Canada, said outside of Alberta, very few fields have the novel pathotypes like this one. This is the first finding in Manitoba.
The discovery of pathotype 3A in the Rural Municipality of Pembina comes after the industry found multiple cases of clubroot DNA and plant symptoms throughout the province of Manitoba since 2013.
“This is yet another cue for the industry to continue to take this disease seriously and implement clubroot management plans,” said Orchard. “We still have an opportunity to get ahead of this disease and limit the impact it has on canola producers and the industry.”
All canola producers are encouraged to grow clubroot resistant varieties, limit the movement of soil, extend rotations to at least a two-year break between canola crops, control canola volunteers and other brassica hosts, and diligently scout.
Symptoms of the disease are most noticeable late in the season and can be visible during and after harvest on plant roots. Producers are strongly encouraged to familiarize themselves with clubroot symptoms and start scouting this fall.
“The development of clubroot and discovery of a pathotype that is virulent to the source of clubroot resistance concerns Manitoba canola farmers,” said Ron Krahn, Manitoba Canola Growers Association director and chair of the Research Committee. “Clubroot is one of the latest challenges in canola production. We know how important canola is for a profitable crop rotation, which is why we feel the research dollars that MCGA spends every year on current production challenges is money well spent.”
Dan told me that because they found it early, they can get ahead of the game. However, if the weed gets away on the farmer, it can spread to the point where growing canola on that field is no longer an option.
In Alberta, that is the current status of fields so infested. As I said at the beginning biosecurity, meaning clean the farm implements before moving from one field to the next, don’t transfer dirt around from field to field. Be careful, those boots may be made for walking but clean them before walking from one field to the next. •