Winegrowers across Oregon are tearing up their grapevines because of an aggressive disease likely brought in by plant nurseries.
Rogue Valley winegrower John Pratt usually harvests about 45 tons of grapes a year. But this year, he brought in just 12.
“Luckily we had 2 blocks that were pretty much disease-free,” he said. “We were able to save those two blocks so we had a little bit of income.”
Pratt’s plants were infected by a disease called red blotch. It discolors grape leaves and delays ripening. When a vine gets infected, growers have to pull out the entire plant. Oftentimes they lose most or all of their plants.
Oregon State University researcher Robert Martin says the disease essentially ruins a wine’s flavor.
“Basically the fruit isn’t uniformly ripe, so at harvest, you have some fruit that’s overripe, some fruit that’s under-ripe,” Martin said.
Researchers only recently discovered red blotch, though there’s evidence that it’s been hanging around North America since the 1940s. They think it came from California nurseries a few years ago.
“When it was discovered in 2012, nurseries spent hundreds of thousands of dollars testing for this virus to clean up their stock,” Martin said. “The year after it was discovered, there were nurseries that cut off sales until they could determine whether or not they were clean.”
Now bugs are spreading red blotch between Pacific Northwest vines. Researchers are trying to identify which bugs are the culprits.
“All aspects of production are being looked at as far as how we might manage this,” Martin said. “But I think the key is going to be finding the vector so we can actually reduce the spread in the field.”