Late-seeded and reseeded canola fields should now be assessed for risk to sclerotinia stem rot infection to determine if a fungicide application will be economical, according to the Canola Council of Canada. Many factors affect the risk of infection including:
Heaviness of the crop canopy
Amount of moisture received in the two weeks prior to flowering and potential for further rainfall
Years since last host crop
Disease incidence in the past
Presence of apothecia in neighbouring fields
Thin stands which result in a light, open canopy will likely help lower risk in a number of locations this year. However, regular precipitation and high humidity at early flowering can still lead to significant disease development in thin stands.
The link https://canola-coun cil. merchantsecure.com/canola_resources/product11.aspx is a “Canola Disease Scouting and Risk Assessment Card.” This card will help determine if fungicide applications are warranted, particularly where yield potential is reduced by late maturity or low plant numbers.