Grapevine Red Blotch Disease: A Threat to the Grape and Wine Industries.

Grapevine red blotch disease emerged as a major threat to the North American viticulture more than 25 years ago. Prior to the discovery of its causal agent, grapevine red blotch virus (GRBV), the disease was likely mistaken for other vineyard problems. Over the last decade and a half, research on red blotch disease focused on GRBV biology; diagnostics; transmission biology; disease epidemiology; ecology of its vector, the treehopper ; and strategies for disease management. Research has also uncovered some of the physiological effects of GRBV on grapevines (inhibition of hexose translocation from leaves to fruits, transcriptional suppression of phenylpropanoid pathways), fruit (low soluble solids, poor ripening, reduced phenolic extractability, high titratable acidity), and wine (altered sensory attributes such as less fruit aromas and poor color and mouthfeel). The economic effects of the disease in different grape-producing regions of the United States are estimated to be as high as $68,548 per hectare over a 25-year vineyard lifespan. Here we reflect on major red blotch research progress and discuss future priorities. We also highlight the contribution of GRBV to the grapevine community as a major driver of enhanced cooperation among researchers, growers, nurseries, extension agents, policymakers, regulators, and service providers. We anticipate that strengthened interactions among all the members of the grapevine community and science-based disease management responses in vineyards will curtail GRBV spread and improve vineyard health.