Issue link: http://read.dmtmag.com/i/51841
VINEYARD populations, but they do not work so well with high populations. Gill's mealybug (Ferrisia gilli), recently identified in Virginia vine- yards, is not seen as commonly in grapes as other mealybugs, but it has been found in California's Sier- ra Foothills and El Dorado County since 2003. It is more common on ornamental plants, and is found on almonds and pistachios in the San Joaquin Valley. It is unknown whether Gill's mealybug can vector leafroll viruses. Central Sierra UC extension viticulture advisor Lynn Wunderlich recently began working with Daane's lab to test Gill's for leafroll transmission. MANAGING GRAPES IN THE WINERY When economics won't allow replanting, or when long-term grape contracts are an issue, sometimes a winemaker must work with lesser quality fruit due to leafroll. Enolo- gist Dr. Jim Harbertson of Wash- ington State University commented on wine-quality issues and possible methods to mitigate leafroll-affect- ed fruit for red winemaking. In addition to lower yields and smaller berries, leafroll quality prob- lems are associated with ripeness; lower Brix, color and pH; higher acidity and potassium; and effects on aroma and flavor. These prob- lems are exaggerated due to cooler locations and vintages, older vines and varieties that typically have low color. Identification of problem vines and blocks is necessary in order to harvest these separately (or not at all), or harvest later to extend maturation, and then process the fruit differently in the winery. "Rosé production may be an alternative, as a way of making lem- onade out of lemons," Harbertson suggested. If red wine is the goal, several techniques are available to improve extraction: increase skin contact time; increase fermenta- tion temperature; use saignee to concentrate higher color/tannin juice; use thermovinification/flash détente; tannin additions (con- densed tannins stabilize color); and retain pomace from the previous ferment and use it for additional tannin extraction. Other processes may also be employed, such as acid adjustment, or blending with better fruit or another variety to improve color/tannins/flavor. Ted Rieger, CSW, is a writer and photographer based in Sacramento, Calif., and has been a contributing editor for V&WM since 1990. Comments? Please e-mail us at feedback@vwm-online.com. 74 VINEYARD & WINERY MANAGEMENT JAN - FEB 2012 WWW.VWM-ONLINE.COM