VINEYARD
and its severity depends on fac- tors that include: rootstock, variety, the interaction between the scion/ rootstock combination, the type of GLRaV, the presence and interac- tion of multiple GLRaVs, growing location and climate. Rootstocks currently considered more resistant to leafroll are AxR-1, St. George, Ramsey and 110R. More suscep- tible rootstocks are Freedom, Har- mony, Kober 5BB and 3309C. A study funded by the American Vine- yard Foundation, begun at UC Davis in 2010 in a 7-acre vineyard planted with cabernet franc, will evaluate nine different rootstocks and six GLRaVs for disease severity and symptom expression. Cabernet franc is prone to lea-
Although red, curled leaves are common, leafroll symptoms can vary depending on variety, rootstock and other factors.
froll symptoms, and is commonly used as an indicator vine for testing in lab and field trials. Other varieties that have shown leafroll symptoms in many growing regions include cabernet sauvignon, gamay, merlot, pinot noir, sangiovese, syrah, zin-
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