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In fields badly infected with sclerotinia, swath when the healthiest plants are ready. These plants will provide most of the yield. Swathing early will not preserve seeds in badly infected plants — those seeds are unlikely to mature no matter when you swath…
Sclerotinia stem rot
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Sclerotinia could be bad this year but the window to apply fungicide has closed for most crops. Rhizoctonia foot rot, shown above, may explain some toppling plants. The weeks leading up to harvest are a good time to scout for blackleg and clubroot… -
Fungicide labels allow for spray up to 50% flower (some are up to 30%). Spraying this late may work well if the crop seems to be flowering for a long time, or the crop is at various stages — either scenario leading to an extended time at 50% flower. Extended flowering does extend the vulnerable period for sclerotinia stem rot… -
When it comes to the sclerotinia stem rot risk, moisture has a much larger influence than temperatures. Infection can be high in hot weather as long as the moisture is there. Moisture can come from rain, relative humidity in the high 80s, or morning dew… -
Split applications, which are approved for some fungicides, may be worthwhile in some cases. For instance, if the sclerotinia stem rot risk is questionable at early bloom, growers could use a split rate and then wait to see if the second application is needed. Another benefit to the split is if the crop is uneven and the flowering period could… -
Moisture is the key factor in sclerotinia stem rot risk. Good soil moisture and a few rains in the period starting two weeks before flowering and carrying through to infection after flowering will greatly increase the sclerotinia risk. Fungicide sprays, if applied, need to go on canola at between 20% and 50% flower. See this week's photo quiz for a… -
Hail that hits canola before flowering or at early flowering may have a minimal effect on yield. Plants will flower longer and compensate… -
Earliest canola is starting to flower this week, which means the sclerotinia spray decision looms. Spray timing, if a grower decides to go for it, should be within the window from 20% to 50% bloom. Canola can reach 20% flower in 4-5 days after first flower. The article also includes information on adding boron to a fungicide tank mix… -
Growers seeing stem lesions or pre-mature ripening should take a closer to identify the cause. There is a good chance it’s sclerotinia. But it could be blackleg. It’s important to identify the cause because it will help in management for next year…
