New fruit fly threatens Minnesota berry, grape crops

Published 10:31 am Thursday, July 18, 2013

ST. PAUL — A harmful new fruit fly threatens Minnesota’s raspberry, blueberry, strawberry, grape and cherry crops.

The tiny spotted wing Drosophila is native to Asia. It was found first in California in 2008 and quickly caused sizeable losses along the West Coast.

The first arrival in Minnesota was detected late last summer. The first confirmed appearance in Minnesota this year was June 27 in Dakota County. An infestation was found in Rice County a week later. Five more reports have since surfaced since then.

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University of Minnesota entomologist Mark Asplen says the flies lay their eggs inside the fruit, the eggs hatch, and the larvae feed on the fruit from the inside, turning it into a mushy mass.

The flies can be controlled with insecticides. Officials urge berry and grape growers to check for the pests and take action, but they concede the fly is so new to Minnesota that there’s a lot they still don’t know.