Issue link: http://winesandvines.uberflip.com/i/116287
grapegrowing test that detects 23 viruses including GRBaV. Eurofins STA Labs implemented a proprietary test for red blotch to their HealthCheck portfolio in November 2012. The Foundation Plant Services' Classic Foundation Vineyard block, used to produce disease-free scion and rootstock vines, has been partially tested and appears to have a very low-level incidence of red blotch virus, reports Golino. Only three of 1,600 vines tested to date were found to have the virus; one each of the following varieties and selections: Chardonnay 68—a private clonal selection no longer listed as available from FPS; Ruby Cabernet 02—a cross of Carignane x Cabernet Sauvignon developed by UCD professor Harold Olmo; Thomcord 02—a black table grape selection, a cross of Thompson Seedless x Concord. Testing of all vines in the Classic Foundation Vineyard, the source of the majority of grapevine nursery stock in California, will be completed in 2013. "If a vine tests positive for red blotch, the grower needs to decide, from an economic standpoint, when is the best time to remove the diseased vines and replant," Golino adds. "This is always a complex decision, and there is no onecase-fits-all answer." Golino encourages vineyard owners and managers to evaluate their vineyards for red blotch disease as they would for any other viruses. Symptoms include blotches of pink or red veins on the leaf undersides in early fall, when grape leaves would normally be turning a uniform gold color. Growers also might notice that the grapes are slow to develop sugar levels sufficient for winemaking, with some grapes never fully maturing. "The good news is that our new Russell Ranch Fo u n d atio n V i n eya rd block has been tested, and there is no sign of red blotch virus in any of those vines." —Deborah Golino, FPS "If there are visual signs of red blotch and poor sugar development, growers should test their vines for both red blotch and leafroll virus because the symptoms of the two viruses are so similar," Golino notes. While the virus likely can be found in all types of grapes, including rootstock, and table and raisin grapes, it was first detected in wine grapes because they are carefully monitored for sugar content to determine harvest date. Based on the wide host and geographic distribution of GRBaV, and the fact that the virus is transmitted by grafting, it is likely that spread primarily occurs through propagation material. Also, an increased incidence of GRBaV over time in young, healthy vineyards that are adjacent to old, infected vineyards suggests the possibility of a vector. Like other viruses, once it is present in a vineyard there is no cure. However, evidence suggests that GRBaV can be eliminated using microshoot tip culture, the same method used to eliminate other viruses, to establish clean Foundation vines. "The good news is that our new Russell Ranch Foundation Vineyard block has been tested, and there is no sign of red blotch virus in any of those vines." This vineyard is propagated exclusively with vines that have been through tissue culture therapy to exclude red blotch and other viruses. Test records from the INCLINE CLUSTER SORTING special delivery Every element of our incline sorting table was developed and tested with guidance from premier winemakers. ■ ■ ■ Superior speed control Multiple models to fit crush pad needs Easy, thorough cleaning ■ ■ H I G H - P E R F O R M A N C E C R U S H PA D E Q U I P M E N T Ozone and UV-resistant food-grade belt www.pnlspecialties.com Remote on/off and speed control Licensed Contractors in CA / O R / WA ■ p. 707 573 3141 1650 Almar Pkwy, Santa Rosa, CA 95403 pr actica l win ery & vin eya rd APRIL 20 13 53 A R M S T R O N G C R E AT E S