—All areas of the Prairies are at risk. Geography does not provide immunity to this disease. —Prevalence of sclerotinia stem rot has a direct correlation to above-average moisture. If a field has regular rains or high humidity or both from two weeks before flowering and through flowering, then infection will occur. If these conditions continue after flower, severity of the…
Sclerotinia stem rot
-
-
-
-
It is not surprising that sclerotinia stem rot disease levels differ from field to field even if fields are in close proximity. Sclerotinia disease level is very dependent on the microclimate within the field. Moist growing conditions (ie. frequent rainfall or high humidity or heavy dews) promote disease development but factors that result in moisture-laden canopies can…
-
Moisture before and during and following flowering was the biggest factor driving up sclerotinia stem rot infection this year. Moisture as rain or high humidity or dew through the period from two weeks before flowering through early podding has increased the sclerotinia risk considerably, no matter the rotation history of the field. Most regions had these conditions this year. Fungicide…
-
Some regions are reporting higher rates of blackleg (shown above) and most regions are seeing sclerotinia stem rot damage. Fungicide is not effective at this stage of the season, but the weeks leading up to harvest are a good time to scout. Its important to know which disease is present in order to plan rotations and varieties for next year…
-
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…
-
-
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…