Sclerotinia Resources

Sclerotinia rating method

Sclerotinia photo gallery

Make a sclerotia depot

Sclerotinia rating method

The optimal canola growth stage for rating is when the seeds are starting to fill the pods and before natural plant ripening, since the whitish sclerotinia stem lesions are more easily recognized.

For accurate representations, rate 200 plants per field (20 successive plants in a row in 10 areas of the field with uniform plant growth). Avoid areas with damaged plants such as lodging, wheel tracks, hail, insects, birds/animals. Rate each plant using the 0-5 scale below, where 0 = no symptoms.

Sclerotinia rating method - Figure 1 = Superficial stem lesions not causing wilt — 1 = Superficial stem lesions not causing wilt

Sclerotinia rating method – Figure 2 = Lesions on stems causing premature wilt up to 25% of the plant — 2 = Lesions on stems causing premature wilt up to 25% of the plant

Sclerotinia rating method Figure 3 = Lesions on stems causing premature wilt up to 50% of the plant — 3 = Lesions on stems causing premature wilt up to 50% of the plant

Sclerotinia rating method Figure 4 = Lesions on stems causing premature wilt up to 75% of the plant — 4 = Lesions on stems causing premature wilt up to 75% of the plant

Sclerotinia rating method 5 = Lesions on stems causing premature wilt on more than 75% of the plant — 5 = Lesions on stems causing premature wilt on more than 75% of the plant

How to rate sclerotinia severity demonstration

When making a sclerotinia risk assessment, enter the number of plants in each severity class, which will automatically calculate the sclerotinia disease severity index (DSI) using the formula below:

DSI = 100 * [ (#plants * 1) + (#plants * 2) + (#plants * 3) + (#plants * 4) + (#plants * 5) ]/(Total number of plants in the sample * 5)

This tool was produced by the Canola Council of Canada and was funded in part by the Government of Canada under the previous Canadian Agricultural Partnership’s AgriScience Program, along with support from Alberta Canola, SaskCanola and Manitoba Canola Growers.