Issue link: http://read.dmtmag.com/i/51841
VINEYARD fandel and chardonnay. Lemberger vineyards In Washington state and New York are commonly infected with leafroll. In California's Sierra Foothills, barbera, petite sirah and primitivo have tested positive for leafroll virus. Riesling, gewürztra- miner and pinot gris have tested positive in New York and Virginia. IMPORTANCE OF CLEAN PLANT MATERIAL Researchers and viticulturists stress the importance of using clean plant material when planting vineyards or replacing vines. Dr. Deborah Golino, director of Foun- dation Plant Services (FPS) at UC Davis, said, "The long-term solu- tion to leafroll problems is having accessible plant material that is not virus-infected." The 2008 Farm Bill established the National Clean Plant Network for grapes and four other specialty crops and autho- rized spending $20 million over four years to establish and improve clean plant centers in the U.S. (See nationalcleanplantnetwork.org) FPS is currently planting and C expanding a new clean stock vine- yard at Russell Ranch, located 4 miles west of the UC Davis cam- pus, funded in part by the 2008 Farm Bill. This includes rootstocks and scion material from FPS' expanding collection of grape vari- eties and clones. The goal is to screen all vine material for 24 dif- ferent pathogens. "The material planted at Russell Ranch will be at a standard that does not exist any- where in the world," Golino said. GLRaVs are graft transmissable, M Y CM MY CY CMY K so a virus in either the rootstock or the scion can infect the entire vine. If a vineyard is regrafted to a new variety, it should only be done on rootstocks where the original scion showed no signs of virus. Growers who use existing vineyards as sources of propaga- tion budwood should be cautious. Potential propagation vines should show no signs of virus the previous season, and preferably be lab test- ed, then flagged to be identified as safe sources of budwood. Some GLRaVs are vectored and 70 VINEYARD & WINERY MANAGEMENT JAN - FEB 2012 Apply this clean white oil early for mite control throughout the season. JMS Stylet-Oil is now available in its conven- tional formulation or an organic formula- tion that is OMRI listed for use in an organic program. Contact JMS for complete information and product data. • Outperforms sulfur as an eradicant on powdery mildew - University researched and rated 10/10. • JMS Stylet-Oil is a stand-alone product for powdery mildew. • Eliminates early season inoculum growth that can cause late-season epidemics. • Unlike sulfur, JMS Stylet-Oil works well in cool weather, protects around the clock, and harmlessly degrades without potential air pollution. transmissible by mealybugs and soft-scale insects. Managing the disease and preventing its spread can best be achieved through coop- eration with neighboring vineyards. This can be problematic in some locations, as some growers are unlikely to remove and replant his- toric vineyards with leafroll disease that are still producing useable grapes, such as old-vine zinfandel vineyards in California. NUMBER OF VIRUSES In recent years, it has gener- JMSWineDex20112.pdf 1 11/15/11 3:48 PM ally been believed that nine or 10 GLRaVs exist. However, continuing JMS Stylet-Oil® - The • Powdery Mildew? • Mites? Choice For Powdery Mildew and Mite control, grape growers have a choice: JMS Stylet-Oil JMS offers grape growers an effective alternative to early-season sulfur treatment. Headquarters 4423 5th Place SW Vero Beach, FL 32968 Office: (772) 562-8770 Fax: (772) 562-7202 styletoil@aol.com Pacific Northwest Region 73585 Williams Lane Pendleton, OR 97801 Office: (541) 276-8566 Fax: (541) 276-6245 styletoil@eoni.com www.stylet-oil.com WWW.VWM-ONLINE.COM