Wines & Vines

March 2015 practical winery & vineyard 45 G R A P E G R O W I N G PWV Staff BY Fifteen years of PD assessment with many possible solutions in sight 51 Microbial origins of key wine aromas, Part II: Volatile fatty acids and sulfurous compounds By Russell Moss T E C H N I C A L R E S O U R C E F O R G R O W E R S & W I N E R I E S Don Neel, Editor practicalwinerylibrary.com Access Practical Winery & Vineyard article archives online. WINE GRAPE GROWER'S ASSESSMENT IN 2015 " T ime may be running out for the California wine industry as we know it," read the first line of the Wine Spectator cover story on Oct. 15, 2000. One look at the vine- yards in Temecula, Calif., in 2000 proved it was a very believable statement. Between 1999 and 2000, 40% to 60% of the vineyards in Temecula were wiped out. The cause: an old foe of the wine industry, Pierce's disease (PD), had a new vector, the glassy-winged sharpshooter (GWSS), which had hitched a ride to California from its native range that runs from Texas through Florida, and north to around the Mason-Dixon line. GWSS was spreading PD in California as never before seen in modern times, first infesting Southern California and then moving north to Bakersfield and Tulare. Experts estimated that, unchecked, GWSS could very well infest regions as far north as southern Oregon. What happened? If the experts were right, then why is California still enjoying record wine grape harvests? In 15 years a lot has happened on many different fronts. Key has been the wine grape grower's assess- ment, which wine grape growers first voted for in the spring of 2002 and overwhelmingly renewed again in 2005 and 2010. It is due for the next vote this spring. When the assessment was passed, the PD/GWSS Board was created to direct how the funds were spent. The PD/GWSS Board has 15 members: eight growers, six grower/producers and one public member. An effort is made to ensure that the members represent all wine grape- growing regions of California. Funds raised from the assessment are earmarked for research and other activities related to Pierce's disease and glassy-winged sharpshooter. The assessment pertains only to grapes grown in California and crushed for wine, and it is a value-based assess- ment, which by law can be no greater than $3 per $1,000 of value. In 2001 the rate was set at $3 per $1,000. From 2002 to 2006 the rate was $2; $1.50 in 2007; $1 in 2008 -09; 75 cents in 2010 -11; $1 in 2012, and 75 cents in 2013 -14. "In the beginning of the PD/GWSS research program, basic research was needed because we did not know much about the disease or the vector," explains Bob Wynn, statewide coordinator of the Pierce's disease control program. "The results of that research have led us to focus on those areas of research that provide the best chance for development of a solution for the disease. The PD/ GWSS Board is now targeting the most promising research areas for investment of grower assessment dollars, which has resulted in the need for less funding." The 2010 vote gave the PD/GWSS Board additional authority to spend assess- ment funds for research and outreach on other pests and diseases that threaten California's wine grapes. Three pests and one disease have been designated since then: the European grapevine moth, vine mealybug, brown marmo- rated stink bug and grapevine red blotch associated virus (GRBaV). Perhaps just as important is that the Glassy-winged sharpshooter is a target pest of the PD/GWSS Board research. PD symptoms on a red grape variety with progressive foliage discoloration. "The Pierce's disease program continues to protect vineyards across the state and holds the promise through its research efforts for a long-term solution, which is why Family Winemak- ers of California (FWC) supports a yes vote on the upcoming referendum." —Paul Kronenberg, president of FWC

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