PORTLAND, Ore. (AP) -- Insect researchers say they aren't seeing much evidence so far of a tiny fruit fly that last year showed a fearsome appetite for Oregon's fruit and berries.

Only about 50 of the spotted wing Drosophila have been caught in traps in western Oregon. It may be that this spring's cold, wet weather and the resulting delay in ripening fruit are keeping them at bay.

The state's strawberries and cherries are ripening this month.

The flies trapped so far appear to be adults that spent the winter here. There's no sign yet that the flies are laying eggs, which could result in successive generations of flies that attack crops as they ripen in rotation. Strawberries, cherries, blueberries, raspberries, peaches and grapes are among the susceptible crops.

"All these insects are regulated by (temperature): The cooler it is, the longer it takes to develop and come out," said Tom Peerbolt, a crop management consultant. Workers for his company, operating on a contract paid for by emergency funding from the Oregon Legislature, monitor traps in the Willamette Valley.

"So far the activity has been quite low, surprisingly low, and I'm keeping my fingers crossed," Peerbolt said.

Amy Dreves, an Oregon State University crop science professor and entomologist, said it's too early to draw conclusions from the low trap numbers.

The fly attacks ripe and ripening fruit, making crops unfit for market.

West Coast farmers produce 76 percent of the nation's raspberries, blackberries, strawberries and cherries. California researchers estimate that a 20 percent damage rate would cost West Coast farmers $511 million, including $31.4 million in Oregon.

Native to Asia, the fly was found in California in 2008 and spread to Oregon, Washington and British Columbia in 2009.

Blueberry farmers in Oregon's Benton County, where it was first confirmed last year, said they turned away U-pick customers because of extensive damage.

Within weeks of the Benton County confirmation, researchers determined it had spread to 14 other counties, from Jackson County in southern Oregon, up the Willamette Valley to Portland and east to Hood River, Wasco and Umatilla counties. It was found in blueberries, raspberries, blackberries, strawberries, cherries, peaches, plums and grapes.

Peter Shearer, superintendent of OSU's research and extension center in Hood River, said some farmers already have the tools to deal with the fly. Oregon cherry growers already spray to kill the western cherry fruit fly. Shearer said most insecticides used for that pest will probably zap the spotted wing Drosophila.

However, farmers who raise other crops may not have the proper spray equipment, Shearer said. And cherry orchardists may have to spray more frequently and use harsher varieties, adding to their expense. Spraying also raises issues of worker safety, drift into waterways and harm to bees that pollinate crops, he said.

Organic fruit and berry growers face an additional dilemma, because they can't use common insecticides and remain certified.


Information from: The Oregonian, http://www.oregonlive.com

Copyright 2010 The AP.

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