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New Fungicides Fight Mildew isease management in vineyards, especially in the humid and often wet climates found in the East, requires that grapegrowers integrate both chemical and non-chemical approaches. This article, part two of two for Wine East, reviews some of the new fungi- cides now available to help growers control both powdery and downy mildew. Among new fungicide products recently D registered for use on grapes in the United States are three difenoconazole products. Difenoconazole (DFZ) is an important "new" (to the United States) sterol inhibitor/DMI fungicide packaged under three different trade names, depending on the "partner" fungicide with which it is mixed. These vari- ous DFZ-containing products have different attributes depending on the mixing partner employed—and in some cases significantly different per-acre costs. It also is important to pay attention to the amount of active ingredi- ent of the different components in each one. During the six trials where we've looked at it (two each during the past three seasons), DFZ has provided excellent to outstanding powdery mildew control, far superior to that Wine East HIGHLIGHTS: • This article, part two of two for Wine east, reviews some of the new fungicides now available to help growers. • Performance of DMi products has been "slipping," but DFZ products provided almost complete powdery mildew control in trials. • several new european products for downy mildew are discussed. EasternWineLab_Mar09.qxp 1/22/09 9:47 AM Page 1 provided by our traditional DMI materials (Rally/Nova, Vintage/Rubigan, Elite/tebucon- azole generics). As many growers are aware, performance of the standard DMI products has been "slipping" in a number of locations during recent years, and during a 2010 Chardonnay trial that we ran, a seasonal program applying Rally at its maximum label rate of 5 ounces/acre provided zero control of the disease on clusters, and they were completely destroyed. In stark contrast, two different DFZ products (Revus Top, Inspire Super) provided almost complete control. EASTERN WINE LABS Serving the Analytical needs of East Coast Wineries WWW.EASTERNWINELABS.COM Ph 609-859-4302 Cell 609-668-2854 chemist@easternwinelabs.com AOAC Member WineEast New products designed to combat powdery and downy mildew undergo multiple trials By Wayne F. Wilcox and Craig N. Austin What was the reason? Lab studies proved what we first suspected: The dose of myclobu- tanil, the active ingredient in Rally required to provide a given level of control of the powdery mildew fungus, is many times greater than the dose of DFZ necessary to give the same control, yet their commercial products deliver comparable amounts of each in the field. No wonder the DFZ products work better. DFZ also has given excellent control of black rot in trials conducted in other states. Labels claim control of a couple of ad- ditional minor/sporadic diseases including anthracnose, but I have no experience or knowledge related to these claims. Three new fungicides Revus Top: A mixture of DFZ and the new downy mildew-specific fungicide mandip- ropamid (the latter is sold alone as Revus), Revus Top is labeled at just one rate, 7 fluid ounces/acre. For the following discus- sion, it will be considered to provide the "full" rate of DFZ. In several of our trials, Revus Top (or the appropriate components used at the same rate) has given excellent control of both downy and powdery mildews Compliance Made Easy Simple – Affordable – ABC/TTB Advice Licensing – Direct Ship, Wholesale & Import Monthly Reporting – Consultation & Training Compliance Outsourcing or One-Time Projects www.williamscompliance.com www.compli-beverage.com Compli East Coast Affiliate Free Consultation 800-790-6838 Call For a Williams Compliance and Consulting Group, LLC Mary Beth Williams, Esq. marybeth@williamscompliance.com Wines & Vines APRiL 2011 47