Red blotch - Ask Extension
Three of my Pinot Noir vineyards have red blotch (one confirmed and two suspected). To what extent is this a death sentence? Should I just remove su...
Knowledgebase
Red blotch #892859
Asked February 19, 2025, 7:58 PM EST
Three of my Pinot Noir vineyards have red blotch (one confirmed and two suspected). To what extent is this a death sentence? Should I just remove suspected vines? And are French-American hybrids (Marechal Foch & Baco Noir) vulnerable ?
Benton County Oregon
Expert Response
To our knowledge, all grapevines of all species may be able to host Grapevine Red Blotch Virus. The question is whether the vines get the virus at propagation or from the virus coming into the vineyard, either by field grafting with infected material (budwood) or from an insect vector (three cornered alfalfa hopper is the confirmed vector but not prevalent in the Willamette Valley). Some wine grape cultivars are less symptomatic and less affected by the virus than others, but not much is known about how severely each cultivar responds to the virus. We know that the more the vines are under stress, the more symptoms will show up. However, this also means that the virus impacts on the vine can be managed with proper attention to vine health (irrigation/vineyard floor management and nutrition).
Having infected vines in your vineyard is not a death sentence for the vineyard. The virus rarely causes vine death. However, the vines will not be able to be "cured" of the virus. In the Willamette Valley, many growers may not know their vineyards have it until they see some red leaf symptoms and test for it. Often there are no reports of yield or fruit quality decline in infected vineyards in the Willamette Valley.
We recommend that growers consider vineyard removal if there is a concern for spread of the virus and/or if the vines have reached a point of having poor fruit quality that makes the fruit unsalable. This includes lack of ripeness (Brix not able to reach 20 or above and significant pH and TA issues). We also recommend that you not propagate from these vines if you are starting new vineyard blocks, providing budwood to nurseries, or using it to graft over, as the virus will move with the wood. If the vines are otherwise healthy and productive, the vines do not have to be removed from the vineyard, as the primary means of spread has been with propagation materials in our region, rather than a known vector (insect) spread.
To learn more about Grape Red Blotch Disease, please see our OSU Extension article and other resources listed within it.
https://extension.oregonstate.edu/crop-production/wine-grapes/how-protect-vineyards-grapevine-red-blotch-disease-grbd
Having infected vines in your vineyard is not a death sentence for the vineyard. The virus rarely causes vine death. However, the vines will not be able to be "cured" of the virus. In the Willamette Valley, many growers may not know their vineyards have it until they see some red leaf symptoms and test for it. Often there are no reports of yield or fruit quality decline in infected vineyards in the Willamette Valley.
We recommend that growers consider vineyard removal if there is a concern for spread of the virus and/or if the vines have reached a point of having poor fruit quality that makes the fruit unsalable. This includes lack of ripeness (Brix not able to reach 20 or above and significant pH and TA issues). We also recommend that you not propagate from these vines if you are starting new vineyard blocks, providing budwood to nurseries, or using it to graft over, as the virus will move with the wood. If the vines are otherwise healthy and productive, the vines do not have to be removed from the vineyard, as the primary means of spread has been with propagation materials in our region, rather than a known vector (insect) spread.
To learn more about Grape Red Blotch Disease, please see our OSU Extension article and other resources listed within it.
https://extension.oregonstate.edu/crop-production/wine-grapes/how-protect-vineyards-grapevine-red-blotch-disease-grbd
