Powery Mildew on grape clusters - Ask Extension
This year I seem to have a lot of powdery mildew on my grapes. This has never happened before. I only have 10 vines of Valiant just as a hobby.
Wh...
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Powery Mildew on grape clusters #873577
Asked June 18, 2024, 10:27 AM EDT
This year I seem to have a lot of powdery mildew on my grapes. This has never happened before. I only have 10 vines of Valiant just as a hobby.
What is the best treatment?
Can I just remove the affected clusters or is it going to spread anyway?
Note that they are on a east facing wall of a shed.
Wright County Minnesota
Expert Response
All the rain and humidity has been very favorable for fungal diseases. Unfortunately once grapes are infected they cannot be cured so removing them is best. If there are uninflected grapes left they can be sprayed with fungicide.
https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/animal-and-crops/plant-health/grape_powdery_mildew.pdf
Controlling the disease this year will make a difference next year.
https://enology.umn.edu/grapes-how/post-harvest-disease-management-grapevine-downy-mildew-and-powdery-mildew
https://ipm.ucanr.edu/home-and-landscape/powdery-mildew-on-fruits-and-berries/pest-notes/#gsc.tab=0
This advice is for much larger operations but will provide some information about what you are up against.
https://extension.oregonstate.edu/crop-production/wine-grapes/how-deal-vineyard-powdery-mildew-outbreak
https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/animal-and-crops/plant-health/grape_powdery_mildew.pdf
Controlling the disease this year will make a difference next year.
https://enology.umn.edu/grapes-how/post-harvest-disease-management-grapevine-downy-mildew-and-powdery-mildew
https://ipm.ucanr.edu/home-and-landscape/powdery-mildew-on-fruits-and-berries/pest-notes/#gsc.tab=0
This advice is for much larger operations but will provide some information about what you are up against.
https://extension.oregonstate.edu/crop-production/wine-grapes/how-deal-vineyard-powdery-mildew-outbreak
