Good Fruit Grower

May 15

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SWD challenges GROWERS High pressure from spotted wing drosophila is likely to be the norm. by Geraldine Warner fter feeling little pressure from the spotted wing drosophila in 2011, Washington State cherry growers battled the pest through the 2012 season. And that's likely to be the norm in the future, Dr. Elizabeth Beers, Washington State University entomologist, warned during horticultural meetings this winter. The first fly of the 2012 season was caught on April 30 in the Tri-Cities area, and many flies were trapped in May and June before peak harvest. Growers reported fruit damage, and 14 flies were caught in packing houses. The spotted wing drosophila (Drosophila suzukii) is a tiny fruit-feeding insect that is related to D. melanogaster, known as the common fruit or vinegar fly. It appeared in the Pacific Northwest in the fall of 2009. Unlike the common fruit fly, which attacks only mature fruit, the spotted wing drosophila attacks fruit while it's still growing on the tree. In 2010, significant numbers of flies weren't trapped until July and August in Washington, although Beers said that might be partly because there were not enough traps out that first season. 2 mm Unlike the common drosophila flies, spotted wing drosophila will attack cherries before they are ripe. Since then, Washington has been trapping from the Canadian border to the Oregon border. In 2011, relatively few regions caught their first fly before the cherries were off the tree. Beers said this might be attributable to a severe freeze around Thanksgiving of 2010 when temperatures plummeted from over 60°F to -5°F in a matter of hours. There was not much pressure anywhere in the state during the 2011 season. After a normal winter in 2011–2012, the pest came right back in 2012 and was active well before harvest, putting the crops at risk. Higher populations were seen south of Interstate 90 than in the northern part of the state, which was the opposite of in 2010. "We warned growers, 'Don't rely on this technology for spotted wing drosophila,' and that's still our recommendation." Watershed year Dr. Peter Shearer, entomologist with Oregon State University, said 2012 was the Mid-Columbia —Elizabeth Beers region's watershed year. Many orchards had fruit damage after not experiencing much of a problem in 2011. An intensive trapping program in the area around Hood River, Mosier, and The Dalles in Oregon showed that p! ANTONIO CARRARO Stability and Reliability in the Orchard & Vineyard $ Bin Trailers In Stock! ABERDEEN CHEHALIS ELLENSBURG LYNDEN OKANOGAN POULSBO OLYMPIA QUINCY SUMNER Your Orchard Specialists . . . 20 May 15, 2013 GOOD FRUIT GROWER Photo by Peter shearer, osu Cherries

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