Should a fungicide be applied to canola now when the oldest plants flower or later with the later-flowering plants?
The Canola Council of Canada says each field should be assessed individually for risk of infection from sclerotinia stem rot.
Early infestations generally cause the greatest yield loss. Scout fields well to determine when the majority of plants (that are the biggest yield contributors) are at the appropriate stage for fungicide application.
Also consider the lateness of the season and frost-free days remaining. Be realistic with yield goals. If the crop is flowering late, is there enough time to gain a return on the fungicide investment?
Bayer Weather Command Centre produces a risk map daily for sclerotinia infection based on weather data (temperature and relative humidity) collected from Weatherbug stations located throughout Western Canada. Visit http://www.bayerweather.ca/andlog into the site with Canola as the “user-name” and Grower as the “password.”