Red blotch in Oregon

Authors: WALTON, VAUGHN - Oregon State University; DALTON, DANIEL - Oregon State University; HILTON, RICHARD - Oregon State University; Sudarshana, Mysore

Submitted to: Oregon Wine Research Institute
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2017
Publication Date: 4/6/2017
Citation: Walton, V.M., Dalton, D.T., Hilton, R.J., Sudarshana, M.R. 2017. Red blotch in Oregon. Oregon Wine Research Institute Grape Day, April 6, 2017, Corvallis, Oregon.

Interpretive Summary:

Technical Abstract: During 2016 we found three potential virus vector insects in Oregon vineyards. Spissistilus festinus was found in Southern Oregon and was recorded in all production regions throughout Oregon during the last 100 years (data from OSU insect collection). We additionally found the treehopper species (Membracidae) Tortistilus wickhami and T. albidosparsus in Oregon vineyards. Tortistilus wickhami was predominantly found in Southern Oregon, with lower numbers of S. festinus and T. albidosparsus. Tortistilus albidosparsus was predominantly found in the Willamette Valley. The seasonal population levels of T. albidosparsus, feeding and egg -laying levels in relation to temperature were described for the Willamette Valley. All suspected vector insect species were consistently found in vineyards where GRBaV spread year over year. The spread of GRBaV is alarming, with observed doubling and 10X increases in study sites from 2014 -2016. Treehoppers are believed to be the most likely species moving Red Blotch between vines. The patterns of virus spread within vineyards closely link feeding symptoms of treehoppers. Our data indicate that GRBaV-infected plants are concentrated and spread from the edge of the sampled vineyard blocks. Virus transmission biology work is currently ongoing (3 months post-inoculation) with more than 600 plants in greenhouse trials. During 2016 we reached ~800 growers though the different channels as part of the extension objective.