Oral: Viral Diseases
Investigating the spread of Grapevine red blotch-associated virus
E. Cieniewicz (1), M. Fuchs (1), K. Perry (2) (1) Cornell University New York State Agriculture Experiment Station, U.S.A.; (2) Cornell University, U.S.A.
Red blotch is a recently recognized viral disease of Vitis spp. The causal agent, Grapevine red blotch-associated virus (GRBaV) has a single-stranded, circular DNA genome (3,206 nt), and is a proposed member of the family Geminiviridae. GRBaV has been detected in all major grape-growing regions of the United States and Canada, likely as a result of the dissemination of infected propagation and planting material. Of major concern to the grape industry is whether GRBaV is transmitted in vineyards. While there is no indication of spread in most areas where GRBaV has been detected, within-vineyard transmission is documented in California, likely due to insect vectors. To identify insect vectors of GRBaV, a detailed census of hemipteran insects in a selected California vineyard was performed. Of more than 50 species screened in 2015, only four species of the families Cicadellidae, Membracidae, and Cixiidae consistently carried genetic elements of GRBaV, as shown by multiplex PCR. The ability of vector candidate species to transmit GRBaV to healthy grapevines is being assessed in greenhouse transmission assays. Understanding the mechanism of transmission will inform proper management strategies to control the insect vector and minimize spread of GRBaV.