COMMON NAME: Grapevine Red Blotch Disease/ Red Blotch Disease
SCIENTIFIC NAME: Grapevine Red Blotch virus / Grapevine red blotch associated virus (GRBaV)
Grapevine red blotch disease is a newly identified disease caused by Grapevine red blotch associated virus (GRBaV) that can be found in both young and mature vineyards. It is present in California, Maryland, New York, North Carolina, Oregon, Pennsylvania, Texas, Virginia, and Washington, and in the province of Ontario, Canada. The disease can cause a significant impact on grape production.
Foliar symptoms – Irregular blotches on leaf blades at the base of the shoots and partial or fully reddening of secondary or tertiary veins is seen on the leaf underside. This reddening symptom of affected leaf blades is often mistaken for symptoms caused by grapevine leaf roll virus. However, red blotch symptoms do not include downward rolling of leaf margins, which is usually seen in leaf roll disease.
Fruit symptoms – Red blotch disease can cause delayed ripening and alter the fruit color and also result in smaller berries. A decrease in 4 to 5 units of Brix (a measure of sugar content) compared to healthy fruits is observed in the fruits of infected vines.
BIOLOGY: The disease is caused by a single stranded circular DNA virus GRBaV, belonging to the genus Grablovirus under the family Geminiviridae. GRBaV is a graft transmissible virus and the three-cornered alfalfa treehopper (Spissistilus festinus) is the vector.
There is no known cure for red blotch disease. The only available management is to replace infected plants in vineyards with clean, certified virus free stocks as the planting material. It is suggested that roguing symptomatic vines and replanting with clean vines derived from virus-tested stocks minimize losses if red blotch incidence is below 30%, while a full vineyard replacement should be pursued if disease incidence is above 30%.
Texas A&M Agri Life Extension – Virus Disease Guide in Grapes https://agrilifeextension.tamu.edu/library/gardening/virus-disease-guide-in-grapes/
Cieniewicz E., Perry K., Fuchs M. (2017) Grapevine Red Blotch: Molecular Biology of the Virus and Management of the Disease. In: Meng B., Martelli G., Golino D., Fuchs M. (eds) Grapevine Viruses: Molecular Biology, Diagnostics and Management. Springer, Cham.
Publication on “Mitigating the Economic Impact of Grapevine Red Blotch: Optimizing Disease Management Strategies in U.S. Vineyards”
Journal from APS Publications on “Grapevine Red Blotch-Associated Virus, an Emerging Threat to the Grapevine Industry”
This factsheet is authored by
Naga Rajitha Kavuri
pursuing a PhD. in Plant Pathology and Microbiology (PLPM)
Factsheet information for the plant health issues represented by the images on the 2020 TPDDL calendar were written by graduate students enrolled in the Department of Plant Pathology & Microbiology DR. DAVID APPEL’s Graduate level Introductory Plant Pathology course (PLPA601) in the 2019 Fall semester. This exercise provides an opportunity for a high impact learning activity where the students are tasked with producing an informational output directed to the general public. This activity provides an opportunity for the students to write and produce a (hopefully) useful product to communicate information on plant health issues to the public.