UC Foothill Grape Day, June 5: To Highlight Local Research, Vine Water Transport, and ZinfandelFoothill Grape Day, sponsored and organized by the University of California Cooperative Extension Central Sierra Farm Advisor Lynn Wunderlich, will be held Thursday, June 5 at the Amador County Fairgrounds. This year’s annual grower meeting will focus on current UC foothill research, vine water physiology, an update on Red Blotch disease and will include a special grower/winemaker panel to discuss the challenges and opportunities with growing and vinifying Zinfandel.
Two current foothill research projects will be highlighted: work with UC Davis Plant Pathologist Dr. Doug Gubler and his graduate student Brianna McGuire on using the powdery mildew index; and work with USDA-ARS researchers Ruby Stahel and Dr. Kerri Steenwerth investigating approaches to managing noxious weeds in foothill vineyards. The noxious weed study is a new project in Calaveras County vineyards adjacent to range lands. Yellow starthistle can be a problem in vineyards, due, in part, because some of the most effective herbicides to control it are toxic to grapes and can’t be used. Stahel is mapping the prevalence of weeds in 4 vineyards and documenting the management practices there.
Wunderlich and McGuire will present their work on powdery mildew. “Powdery mildew continues to be the main disease grape growers treat for,” Wunderlich said, “and I’ve been working to secure foothill weather stations that calculate the mildew index and to make the information publicly available on UCIPM”.
“The foothills pose a challenge due to our wide range of growing elevations, slopes, and microclimates”, Wunderlich noted. “For many years growers in other regions have had access to this type of data, and it is time for us to learn something more about mildew here, so that, ideally, we can save sprays but maintain quality”. With collaborative support from private growers, the Amador Winegrowers Association, and UCIPM, two powdery mildew stations were installed in the Shenandoah Valley of Amador County last year. This year, with support from the Fish Friendly Farming program and a grant they received from the Sierra Nevada Conservancy, two more stations were placed in El Dorado County. With assistance from Dr. Doug Gubler and his graduate student Brianna McGuire, mildew studies are being conducted in the foothills to evaluate grower spray programs compared to station programs. Mildew spore trapping is also being conducted this year.
Andrew McElrone, USDA Research Scientist affiliated with the Department of Enology and Viticulture at UC Davis, will give a special presentation on “How grape vines use water: a journey through the vine’s vascular system”. McElrone’s research aims to develop sustainable water-use strategies through improved understanding of drought resistance, deficit irrigation strategies, and water use quantification, timely information for a drought year. He will cover vine physiology related to water transport, including the effects of rootstocks on vine water use.
Rhonda Smith, UCCE Sonoma Viticulture Advisor, will present an update on Red Blotch disease. Smith has been doing research on the symptomology of Red Blotch in white varieties.The meeting will end with a grower/winemaker panel on Zinfandel. Panelists include Tegan Passalacqua, winemaker and vineyard manager for Turley Wine Cellars, Chris Leamy, Terra d’Oro winemaker and vice-President for Zinfandel Advocates and Producers (ZAP), and Kevin Steward, vineyard manager for Trinchero Family Estates. “Zinfandel continues to be an important variety for our region,” Wunderlich said. “Zinfandel is a part of the foothill viticultural heritage, but there are different ideas out there now about how it is best grown and what attributes create wine quality”.To register for Foothill Grape Day, contact Robin Cleveland at (530) 621-5528 or go to http://ucanr.org/foothillgrapeday.
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