Researchers expect this to be a bad year for bugs in Oregon’s vineyards.
Oregon State University’s Wine Research Institute issued a warning saying wine grape growers can expect increased pressure from brown marmorated stinkbugs in particular and spotted wing drosophila to a lesser degree.
A warmer-than-average growing season last year and a mild winter set the stage for high populations of both, according to OSU.
The pair are two of agriculture’s most damaging pests; both feed on tree fruit and berries, including cherries, raspberries, blackberries and blueberries.
For wine grape growers, the highest risk areas for stinkbug damage are the Chehalem Mountains, Dundee Hills, Eola-Amity Hills, and McMinnville American Viticultural Areas, or AVAs. Southern Oregon and Columbia Gorge AVAs are at somewhat reduced risk.
Brown marmorated stinkbugs eat plant tissue and the grape berries, potentially contaminating the grapes and hurting wine quality. They apparently move into vineyards late in the season after other crops have been picked. An OSU news release said they engage in “hill topping” behavior, meaning they overwinter at higher elevations. Many vineyards are planted on rolling slopes, putting them in favored stinkbug habitat. Wineries have found them in buildings and dead bugs have been found in fermenting wine, according to OSU.
Vaughn Walton, a professor and horticultural entomologist at OSU, is researching the use of tiny parasites to control the stinkbugs.
Spotted Wing Drosophila prefer other crops, particularly berries. It saws a hole in berries and lays an egg inside, which hatches and feeds on the host from the inside, causing it to collapse in a gooey mess.
The tiny flies may be drawn to grapes damaged by rain, birds or fungus, according to the Wine Research Institute.