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March 2018 WINES&VINES 39 GRAPEGROWING The references for this article are available online at winesandvines.com/features. maximum sugar content around 24º Brix. It is likely that different cultivars have different maximum sugar levels, and this needs further research. Once berries reach their maximum sugar content, any further increase in Brix is the result of the berry dehydrating and shrink- ing, not from an increase in sugar content. Unpublished research results have shown that after ripeness, berries generally lose 5% in weight for each degree increase in Brix. Although late-season weight loss varies by cultivar, when dehydration is visible and ber- ries show wrinkling and shrinkage, the crop has already lost about 10% in weight. 6 Goldilocks principle Withholding drip irrigation after véraison can cause too much water stress before harvest and reduce yield and potential profits for the grower. Late-season irrigation can be thought of in terms of the "Goldilocks" principle: Not too little: Avoid too much stress and berry dehydration before harvest. Not too much: Avoid new canopy growth. But just right: Alleviate berry dehydration if there is extended hang time and replenish vine's storage reserves before dormancy. The bottom line Based on these research results, growers and winemakers should have no worries or fears that drip irrigation applied during véraison and through harvest will dilute fruit flavors or nega- tively impact wine grape quality. This does not apply to overhead sprinkler irrigation, which can mimic ill-timed rain near harvest. Late- season drip irrigation can help prevent berry dehydration and potential loss of yield, and keep vines healthy and prepared for winter. Dr. Yun Zhang is a post-doctorate fellow and adjunct faculty in the Viticulture and Enology Program of Wash- ington State University. Dr. Zhang's research interests include grape berry ripening, water relations and irrigation management. She is conducting a research project studying the impacts of heat stress and drought stress on grapevine growth and development. Melissa Hansen, research program manager for the Washington State Wine Commission, works to make viticulture and enology research supported by the Wash- ington wine industry more accessible to the state's growers and winemakers. Hansen spent nearly 20 years as a journalist for Good Fruit Grower magazine and was involved with California's table grape and tree fruit indus- tries for 15 years. Additional funding for this project came from the U.S. Depart- ment of Agriculture's Northwest Center for Small Fruits Re- search, Rhone Rangers, the WSU Horticulture Department and Chateau Ste. Michelle Distinguished Professorship. TTB LABEL APPROVALS Low per-label costs Gov't. Liaison Negotiations or Footwork Reasonable Hourly Rates TRADEMARK SEARCHES As Low as $185 Your trade names or designs are searched at the U.S. Patent Office to help establish valuable ownership or avoid costly legal liability. Over 100 years' total staff experience handling every government liaison need for industry. Phone or write for details. 200 N. Glebe Rd., Suite 321 Arlington, Virginia 22203 Phone: (703) 524-8200 Fax: 525-8451 TOLL-FREE 1-800-642-6564 Major Credit Cards Accepted www.trademarkinfo.com Since 1957 GovtLiaison_Dir08 11/29/07 2:00 PM Pag Promote your wines to leading Zinfandel enthusiasts and extend your winery's relationship in the market. Join Us! We are champions of Zinfandel— America's Heritage Wine Become part of our proud legacy zinfandel.org • 530-274-4900 Zinfandel Advocates & Producers is a 501(c)(3) non-profit organization. ZAP is dedicated to advancing public knowledge of and appreciation for American Zinfandel and its unique place in our culture and history. You know how good your Zinfandel is... For your nearest dealer, contact: BRANCHLOK™ Used for lateral training of trellised branches and cordons to 12-14 gauge wire. Branchlok™ is available in three lengths: 2½", 3¼", 3 ¾". Patent No. 4,665,000 Toll-Free: 877-552-4828 909-464-1373 • Fax: 909-464-1603 www.agfast.com WineVineBranchLokAD.qxp_Layout 1 12/1/16 2:50