A new case of clubroot has been found in the Rural Municipality of Lorne, Manitoba Agriculture says in its Aug. 15 Manitoba Insect & Disease Update.
That brings the number of clubroot cases in Manitoba canola fields discovered so far this season to nine.
“Manitoba Agriculture continues to encourage growers to scout any areas in their canola fields where the crop in under-performing,” the insect report says. “Growers should contact their local Manitoba Agriculture office if clubroot is suspected. Field location remains confidential, but a government employee will need to confirm the case and can work with the producer on a management plan.”
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.
As the name implies, the roots of clubroot infected canola are distorted, which interrupts the flow of nutrient and moisture to the plant, dramatically reducing seed production.
Where the infection is not widespread farmers should hand pull infected plants and destroy them, Manitoba Agriculture plant pathologist Holly Derksen said in an earlier interview. However, often by the time the disease is noticed its widespread in a field.
Six of this year’s nine new clubroot infections were found in the R.M. of Pembina in south-central Manitoba, where the disease has been found before.
But for the first time one clubroot case was found this season in the R.M of Dufferin and now two in Lorne.
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.
Clubroot was first detected in Alberta canola in 2003 in Sturgeon County northwest of Edmonton.
Manitoba started testing soil to for clubroot spores in 2009.
Spores were found in 2011, but no disease symptoms were seen in canola plants. The 2011 results were made public in 2012.
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.