A third case of clubroot was recently found in the Rural Municipality of Lorne, bringing the Manitoba total for the season to 10.
Earlier this summer two other cases were confirmed in Lorne along with one in the Rural Municipality of Dufferin and six in the Rural Municipality of Pembina, Holly Derksen, Manitoba Agriculture field crop pathologist, said in an interview Aug. 30.
“I know this is just the tip of the iceberg,” Derksen said. “I think the biggest thing for this coming year and future years is going to be the ability of (Manitoba) growers to get their hands on clubroot-resistant varieties. It’s going to be up to the seed companies to realize where these varieties need to be funnelled into. It’s not just Alberta.”
Previous to this year, clubroot symptoms in canola had been found in only five municipalities — Pembina, Louise, Portage la Prairie, Westlake-Gladstone and Swan Valley West.
Farmers should be checking canola fields for this potentially destructive disease as it’s easier to mitigate the impact when discovered early, Derksen said.
If caught soon enough it’s practical to hand-pick infected canola plants and destroy them.
Although clubroot spores can survive in soil up to 20 years, without a host plant, many will die sooner than that. That’s why not planting canola in an infected field for at least two years is recommended, Derksen said.
Crop rotation, planting clubroot-resistant varieties, reducing tillage and cleaning equipment after working in an infected field are ways to battle the soil-borne pathogen that strikes cruciferous crops including canola, mustard, cabbage, cauliflower, broccoli, and rutabaga as well as weeds in the same family.
Farmers can try to work infected fields last and then clean their equipment to avoid spreading the disease to other fields.
Clubroot has also been found in North Dakota this year.
Derksen is urging farmers who suspect clubroot in a field to contact Manitoba Agriculture to confirm it.
Manitoba Agriculture will also take a soil sample to get a clubroot spore count.
“At this point in time we are doing it to try and monitor changes over time, but there’s really no need to do that in thousands of fields,” she said, adding free soil testing probably won’t be offered forever. “When it’s in handfuls of fields it’s interesting to have that measurement.”
Clubroot is not a reportable disease in Manitoba as it is in Alberta. As a result, infected Manitoba fields are not made public, although Manitoba Agriculture does make it public which municipalities have had clubroot infections.
Manitoba’s first case of clubroot in canola was found in 2013.
In 2014 Manitoba had 13 cases, but 11 were based just on soil samples, with no visible signs of disease in canola.
Previous to this year clubroot symptoms in canola had been found in only five municipalities — Pembina, Louise, Portage la Prairie, Westlake-Gladstone and Swan Valley West.