The first Sclerotinia risk map for canola is planned for June 3. The first map will provide information on planting dates of canola (when 50% of the crop was planted in each county) and also will provide data on the soil moisture conditions. Moisture in the top four inches of soil is critical to the model for Sclerotinia since the upper two inches of soil must be saturated for 10 days for the Sclerotinia spore-producing structures, the apothecia, to form. The apothecia, tiny mushroom bodies resembling diminutive golf tees, release millions of air borne spores that initiate Sclerotinia infections. The spores initiate growth on dead plant tissue, primarily the cast dead petals. The infection areas must be wet for the better part of 40-48 hours.

Subsequent risk maps will address the risk of Sclerotinia infection in various areas of North Dakota and northwestern Minnesota. We will have better weather information this year than last with the addition of a North Dakota Agricultural Weather Network (NDAWN) station at Roseau in Roseau County, Minnesota and access to University of Minnesota weather station data at Karlstad in Kittson County and Williams in Lake of the Woods County, Minnesota.. The NDAWN station at Roseau was purchased by funds from a Sclerotinia grant to the University of Minnesota. In addition, we will have new NDAWN stations in North Dakota at Fingal and Pillsbury in Barnes County, Wishek in McIntosh County, Karlsruhe in McHenry County, Roseglen (Plaza) and Ross (Stanley) in Mountrail County, Berthold in Ward County and Crosby in Divide County. Actual risk will not begin in any given area until the earliest planted canola in the area begins flowering or until petal cast occurs.

The risk map will be posted on the web on the Northern Canola Growers Association web site: http://www.northerncanola.com
and on the NDSU Extension Service Web site: http://www.ag.ndsu.nodak.edu/aginfo/sclerotinia/sclerotinia.htm.