Scientists identify fruit fly pest in wine grapes

Washington, Oct 16 (ANI): The recent discovery of a spotted wing fruit fly- Drosophila suzukii-in a sample of Willamette Valley wine grapes in Oregon prompted reports of its occurrence in a variety of fresh fruits, including blueberries, peaches, raspberries, strawberries, blackberries, plums - and now in grapes, according to a study.

Amy Dreves, a research entomologist at Oregon State University, has said that new reports of its occurrence have been confirmed almost every week since OSU researchers first identified the fly in a sample of Oregon blueberries in August.

"This is an insect that, up to last year, had never been seen in the continental United States. Now, suddenly, it is showing up in lots of places," said Dreves.

Losses to fruit crops have been significant in some places this year, according to OSU entomologist Vaughn Walton.

The researchers are now reporting that adult Spotted Wing Drosophila had emerged from wine grapes that had been collected in the northern Willamette Valley two weeks earlier.

The Oregon Department of Agriculture also confirmed that the flies were emerging from infested red table grapes collected from the Willamette Valley.

At this stage, growers have not seen noticeable damage to harvested grapes, said Dreves, and the harvest of grapes is nearly complete in the Willamette Valley without signs of Spotted Winged Drosophila impact.

Much of western Oregon's growing season would seem to favour conditions favoured by these flies, which means that most of Oregon's berry crops could be at-risk during the growing season, according to Dreves.

And because Oregon has a variety of crops that ripen at different times during the season, the spotted wing Drosophila fly could move from one crop to another as the season progresses, and populations could build up to high numbers in many crops.

On the other hand, Walton said that the fly might be gone by next season, pointing out the uncertainty associated with a new invasive species.

Planning for the worst, the OSU team is working with colleagues in the USDA Agricultural Research Service and ODA to develop management plans for this new pest in Oregon.

For now, Dreves said, two principles are at the heart of controlling the fly regardless of crop.

First, reduce the fly's breeding sites by immediately removing and disposing of the source - infested fruit and monitor for the presence of adult flies before they lay eggs. (ANI)