Growers in areas where blackleg infection was known to cause yield loss last year may choose to apply fungicide early in the season. Here are factors that increase the blackleg risk. The more of these risk factors that apply, the greater the risk:
—Tight canola rotation
—Using the same variety in the rotation
—Yield loss to blackleg in previous years…
Blackleg
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High levels of blackleg have been found in some canola fields this year. Quite likely blackleg was present the last time canola was grown on these fields but went undetected based on a lack of obvious yield losses. Just before or while swathing are the best times to check plants for blackleg and other diseases. Uninfected parts of the plant…
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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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Growers are encouraged to check maturing crop for blackleg infection. It’s too late for fungicide to provide any benefit, but checking now can help plan for next year. Try to figure out why blackleg is worse than usual. It could be tight rotation. It could be use of a less resistant variety. Take steps to avoid that situation next time…
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Early blackleg infection — from the cotyledon to 3-4 leaf stages — leads to the greatest yield loss. If growers see blackleg lesions on cotyledons or leaves early in the season, this may indicate a greater risk of potential blackleg problems. Fungicides are registered for blackleg management in canola…