An invasive fruit fly from Asia is causing trouble with the economics and growing techniques for raspberries, blueberries and grapes in Minnesota.
The potted wing drosophila damage crops, shorten harvesting seasons, increase insecticide use and reduce income for producers. They were first detected in the state in 2012.
The flies lay eggs in ripening fruit. The eggs grow into small white worms that turn fruit into mush.
Fall raspberries are the most vulnerable fruit, but the bugs also invade blueberries, blackberries, summer strawberries and grapes that have soft skins.
University of Minnesota Extension entomologist Bill Hutchison estimates that 20 to 25 percent of berry growers in the state have suspended production or gone out of business because of the bugs.