Grapevine Red Blotch Disease (GRBaV)

Grapevine Red Blotch Disease (GRBaV)

Grapevine red blotch disease occurs in some vineyards in the northern San Joaquin Valley. Rhonda Smith, viticulture advisor in Sonoma County wrote an excellent article on her Viticulture web page: http://cesonoma.ucanr.edu/viticulture717/.

According to Dr. Mysore (Sudhi) Sudarshana, Research Biologist, USDA-ARS, whether or not to remove infected vines depends on the quality of the wine made, because affected grapes will reduce wine quality. Red blotch would lower the revenue of high-value wine but not of low-value wines. He noted that some growers in Napa are removing infected vines and sometimes whole blocks.