Some Maine farmers estimate crop loss to new invasive fruit fly

Spotted Wing Drosophila
Griffin Dill

The Spotted Wing Drosophila fruit fly (male at left, female at right), has arrived in Maine in the past year. The fly likes ripening fruit, making it a potentially serious threat to Maine crops.

MONMOUTH — They're here, they're statewide, and they're "rugged."

A researcher who spent the fall surveying farmers said Monday that initial response indicates more than half saw Spotted Wing Drosophila fruit flies around their crops this fall, a year after it was found in the state for the first time. David Handley's traps at Highmoor Farm caught the fruit flies up to the end of November.

"It kind of points to the fact of how rugged this thing is. After a couple of what we would normally consider killing frosts they were still laughing at us and we were still catching them in high numbers," said Handley, a vegetable and small fruit specialist for the University of Maine Cooperative Extension.

The Spotted Wing Drosophila, native to Northern Asia, slits a hole in ripening fruit to lay its eggs. It spoils the fruit, though the raspberries, blueberries and other soft-skinned produce can look fine for a day or two — long enough to be picked, sold and become an unpleasant surprise.

Their numbers picks up in late summer. One female can lay 300 eggs during its 14-day lifespan.

In early responses, Handley said four raspberry farmers estimated 20 percent crop loss. Of 30 highbush blueberry growers, fewer than half reported seeing the flies and 10 percent found larvae in fruit and took a measure such as spraying, to combat the pest.

"Hopefully our trapping made growers aware of this so they were trying to prevent infestations," he said. "Not only did we catch them in every area we put a trap, in some cases we were catching them by the thousands on a weekly basis. That's amazing."

David Yarborough, a wild blueberry specialist and professor of horticulture at the University of Maine, said it's been hard to measure how hard the fruit fly hit that crop. Ruined berries often shrivel and drop to the ground.

Maine appears to have had its second largest wild blueberry crop ever this season, an estimated 95 million pounds, he said.

"At this point in time we don't feel they made a significant injury to the crop but that doesn't mean they couldn't in the future and they won't if we don't address them and be aware of them," Yarborough said. "We don't know, we could have potentially had a bigger crop than we did."

Winter will be spent researching means to combat the fruit fly, talking to farmers and educating consumers, Handley said.

People want to buy local, he said. At the same time,  "we've got to be able to have good, clean product for them or you're going to be out of business."

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PAUL ST JEAN's picture

Time flies like an arrow.

Time flies like an arrow. Fruit flies like a banana.


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