By Layne Wade, Technical Sales Support, Arysta LifeScience

Vineyards both large and small often encounter the same disease in their grapes: Powdery mildew.

Powdery mildew, which is native to eastern North America, can affect all green tissues of the grapevine. The disease gained notoriety when it was introduced into European vineyards in 1845, causing severe losses as it spread rapidly throughout the continent. If left uncontrolled, Powdery mildew can destroy infected clusters outright, or can reduce their quality, predisposing them to Bunch rot infections.

Grapes become extremely susceptible from the immediate pre-bloom stage through fruit set. Severe disease on grape clusters is usually a result of uncontrolled infections during or shortly after this period, making treatment during delayed dormancy even more important.

The delayed dormancy stage of grape plants’ development is a good time to consider a preventative fungicide treatment.

“Grape growers with small ‘backyard operations’ and those with sizeable vineyards all know three keys to successful fruit are canopy management, pest control and disease control,” said Layne Wade, Technical Sales Support, Arysta LifeScience. “On the latter, regions vary on disease issues, and a major issue may be heavy in one area and not exist at all in another. Local knowledge of your growing area is invaluable, as is a preventative fungicide treatment.”

In years of high rainfall in early spring (during bud break and leaf emergence), another disease also may threaten grapevines: Phomopsis leaf spot. CAPTAN Fungicide, from Arysta LifeScience, sets the standard for management of this disease. CAPTAN has a multi-site mode of action and is a broad-spectrum fungicide, making it an excellent fit in resistance management programs. For convenient, flexible application, product formulations include:

Delayed dormancy fungicide applications kill fungal pathogens that overwinter in the woody parts of the grapevine. Fungicides aren’t able to kill all the fungus inoculum, but it is possible to curb spore production. This reduces disease pressure during the growing season.

Additionally, grape growers may choose CASORON^® CS Herbicide for reliable, long-lasting, residual weed control. When air/soil temperatures are below 70 degrees F, apply CASORON^® CS at 1.4 to 2.8 gal/A in a tank mix with a burn-down herbicide to existing weeds or alone to bare, undisturbed soil from about December to March, followed by 0.25 to 0.5 inches of irrigation or before moderate rainfall. The product forms a vapor barrier that prevents annual weed seeds from germinating and tough perennial weeds from emerging.

To learn more about applications during delayed dormancy in grapes from the Arysta LifeScience portfolio of crop protection products, contact your crop protection retailer, visit www.ArystaSpecialty.com/Grapes or call 866-761-9397.

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