Vermont Grape IPM: Disease management season is right around the corner

Good afternoon. UVM Fruit Program M.S. student Bethany Pelletier has written this week’s message. -TB

For many of us, bud break came up quick here in the Champlain valley. This means a real push to make sure your pruning has set you up for a clean, orderly season (or as much as we can hope). Make efforts to get your vineyard as sanitized as possible, getting old wood cleared and well away from your working plants to reduce as much of last year’s inoculum as possible. Fungal disease loves to sit in that old grape wood, so leaving it laying in the vineyard can have you fighting an uphill battle.

Speaking of inoculum, get your sprayers ready! Those with organic spray programs or with heavy disease pressure from previous years will want to begin your spray program around 3” of growth. For us here at the UVM Horticulture Research and Education Center, this likely means a spray sometime next week before a rain event. For those with a good handle on your disease pressure and using highly effective fungicides, you can get away with waiting until 5-8” of new growth.

As for what to spray, keep in mind what we are working against. Our key early season disease is Phomopsis, but we’re keeping in mind any downy mildew or black rot as well. Anthracnose is also an early season disease, and while not present in all vineyards those who have it should also be spraying for it at this time. Key fungicides in your arsenal against these early season diseases may include mancozeb, captan, or ziram. For organic growers, copper has shown some efficacy, but good sanitation practices are really your first line of defense here.

With nervous excitement, I am happy to be starting this next season of grape growing! I wish a sunny and not-so-rainy spring to you all! -BP

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The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, UVM Extension, USDA NIFA E-IPM Program, and USDA Risk Management Agency.

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