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Title: Grapevine red blotch-associated virus is widespread in California and U.S. vineyards.

item Sudarshana, Mysore
item Gonzalez, Asaul
item DAVE, ASHITA - US Department Of Agriculture (USDA)
item WEI, ALAN - University Of California
item SMITH, RHONDA - University Of California - Cooperative Extension Service
item ANDERSON, MICHAEL - University Of California
item WALKER, M - University Of California

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2013
Publication Date: 6/15/2013
Publication URL:
Citation: Sudarshana, M.R., Gonzalez, A., Dave, A., Wei, A., Smith, R., Anderson, M.M., Walker, M.A. 2013. Grapevine red blotch-associated virus is widespread in California and U.S. vineyards. . Phytopathology. 103:458.

Interpretive Summary:

Technical Abstract: In fall 2011, Grapevine red blotch-associated virus (GRBaV), a circular ssDNA virus, was detected in grapevines exhibiting leaves with red blotch symptoms in Napa, CA. Extensive sampling of symptomatic grapevines in California vineyards and analysis of the nucleic acid fractions by SYBR®Green qPCR assay indicated that this virus is widely distributed in California vineyards. In several vineyards, disease incidence was >90% and GRBaV was detected in ~95% (n=327) of grapevines showing red blotch symptoms and in ~2.5% (n=757) of asymptomatic grapevines. Virus was detected in asymptomatic first-leaf plantings and in symptomatic grapevines in vineyards up to 25 years of age. Fruit on GRBaV positive grapevines had reduced total soluble solids and increased titratable acidity. Among tested grapevine samples with red leaf symptoms, a higher proportion was positive for GRBaV when compared with grapevine leafroll-associated viruses. Red leaf grapevines in at least seven California counties and from grape growing regions across the U.S. have been confirmed to be infected with GRBaV. It appears that grapevine red blotch disease is endemic in California and has been overlooked because of its leafroll-like symptoms. Because of its adverse effect on fruit quality, red blotch disease poses a significant threat to California vineyards.