Invasive Flies Arrive in Minnesota

A new fruit pest has found its way into our state, according to officials from the Minnesota Department of Agriculture.

The spotted wing drosophila

The spotted wing drosophila (Drosophila suzukii), a species of fruit fly from southeast Asia, has been found in berry patches in Ramsey and Hennepin counties. The drosophila, which was first detected in the United States in Hawaii in the 1980s, feeds on healthy and ripening fruits such as blackberries, raspberries, blueberries, and cherries. The fly arrived on the mainland of North America more recently, being found in California in 2008, and has since spread to several states across the country.

According to Bob Koch of the Department of Agriculture, the drosophila cuts a small incision into the skin of the fruit and lays its eggs inside so that they can feed on the seeds. The infested fruits often have no noticeable signs on them until after they are harvested. The incision can become a source of secondary infections by bacterial and fungal pathogens

Drosophila larvae in a strawberry

"If you start to see a bunch of maggots showing up in some of the fruits that you've harvested, and if it was fruit that looked fine at harvest time, then that might be a pretty good indicator that that pest is in the area," said Koch.

Anybody suspecting that they have an infestation of drosophila in their fruits is asked to call the state Department of Agriculture.