If infection rates are high, determine where most of the yield is. If it’s in the healthy plants, then make harvest decisions based on what’s best for the healthy plants. That means swathing at 50% to 60% seed colour change for ideal yield and quality. If most of the yield is in the infected plants, then earlier swathing — at…
Diseases
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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…
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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…
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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…
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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…
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Fields all across the Prairies are reporting aster yellows. The phytoplasma infection causes misshapen pods and flower buds. Most fields don’t go above 1% infected plants, however, some fields are reported this year with rates at 5% to 8% of plants infected. A 10% infection rate results in 3% to 7% misshapen seeds or no seeds at all…
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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…