CANOLA QUIZ – Sclerotinia risk for 2021

Open canopies, lower soil and canopy moisture, and early flowering will reduce risks for sclerotinia stem rot on many farms across the Prairies in 2021. This quiz will help agronomists and farmers assess the risk for each field.

1. Dry conditions at the beginning of flowering can change to wet conditions during flowering, which may increase disease risk. However, keep in mind that it takes __________ for sclerotia to germinate and produce the spores necessary for infection.
2. When does the application window close for most sclerotinia stem rot fungicides?
3. The sclerotinia pathogen doesn't like hot weather and fungicide performance is reduced in hot weather. Fill in the blank in this sentence: The disease risk is limited when current conditions are dry, and max daily temps are ___ or more.
4. We talk often about the benefits of uniform emergence, with all plants at the same stage. That sure helps when it comes to fungicide timing. Of course, things don't always work out that way. Which of the following would be the most accurate agronomy statement for fungicide timing in an uneven crop?


For lots more on sclerotinia stem rot, including the pathogen, the disease cycle and how to manage it, start with the Canola Encyclopedia. The encyclopedia chapter includes this new graphic on the disease cycle: