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24 WINES&VINES January 2017 WINE INDUSTRY NEWS P enticton, British Colum- bia—The invasive insect brown marmorated stink bug recently was found at a ri- parian site near Penticton in Brit- i s h C o l u m b i a ' s s o u t h e r n Okanagan Valley. Originally from Asia, the stink bug has become a leading cause of damage to tree fruits on the East Coast. Its detection in the Okanagan is the first in a major fruit-producing area of British Co- lumbia, although there are signs that it may have become estab- lished in pockets of the province's Lower Mainland. Vancouver is the country's busiest port of entry, and several bugs have been inter- cepted on incoming shipments in recent years. Betsy Beers, an entomology professor at Washington State University in Wenatchee, said the appearance of the pest in Pentic- ton means it's only a matter of time before it wings its way across the U.S.-Canadian border to Okanogan County, Wash. The bug has been identified in 17 counties in the state to date. The good news for everyone, however, is that the pest takes years to become established in sufficient numbers that it can cause economic damage to agri- cultural crops. "We have had no absolute, verified reports of damage in Eastern Washington in our pri- m a r y a g - p r o d u c t i o n a r e a s , " Beers said. "Usually, the last frontier is to move out into agri- cultural areas." Small you-pick operations within the city limits of Vancou- ver, Wash., have been the only significant agricultural impacts seen to date, consistent with the pest's preference for temperate, urban locations. The pest typically overwinters in homes and avoids the climate extremes typical of the interiors of British Columbia and Washington. While the number of bugs de- tected in Eastern Washington surged into the hundreds this year from just a few dozen in 2015, the largest numbers were found in the residential areas of Yakima and Walla Walla. Walla Walla grapegrowers aren't expressing alarm, however. Jason Magnaghi, viticulturist with Figgins Family Wine Estates in Walla Walla, said the pest isn't present at levels that would dam- age wine quality. While a crushed stink bug pro- duces an unpleasant odor and could potentially taint wines in a manner similar to Asian lady bee- tles, Magnaghi said the insects have been drawn more to or- chards than vineyards. "Grapegrowers right now seem to be not so much threat- ened by this pest as a number of other crops—especially if they're making their grapes into wine, which the vast majority of grape- growers are," Beers said. "The threshold tolerance seems to be really high. I believe what I've heard mentioned is four bugs per cluster of grapes, as you harvest them." According to rules of thumb from the Washington Association of Wine Grape Growers, each vine has about 40 clusters, and there are ap- proximately 400 vines per acre. At this rate, a grower would need ap- proximately 64,000 bugs per acre to detect a problem in finished wine, and detections in Washington this past summer maxed out at two bugs for an entire vineyard. —Peter Mitham Okanagan Valley Grapegrowers Face the 64,000-Bug Question " Grapegrowers right now seem to be not so much threatened by this pest as a number of other crops." —Betsy Beers, WSU Wenatchee