Spotted Wing Drosophila—Drosophila suzukii
The spotted wing drosophila (SWD) is a fruit fly orginally from Asia, was found in Hawaii in the 1980s, in California in 2008, in Michigan in 2010 and in Maine in 2012. It looks very much like other fruit flies, but unlike most fruit flies, which attack rotting or over-ripe fruit, SWD attacks healthy, undamaged fruit. It has the potential to be a serious pest of strawberries, raspberries, blackberries, blueberries and other soft fruit. To date it has not been found on cranberries, nor on hard fruits such as apples.
More information on fruit flies
The spotted wing drosophila adult is approximately 1/16 to 1/8 inches long (which is very, very small). The males can be identified by the dark spots on the wings; the females do not have these spots.
The female uses a prominent, sawlike ovipositer to deposit eggs just under the skin of the fruit. Thread-like "breathing tubes" can sometimes be seen protruding from the fruit.
Eggs hatch inside the fruit. The larvae are tiny, white, cylindrical maggots, approximately 1/8 inch long when fully grown.
Click on images to view full-size
Identification and Control Information
- Spotted Wing Drosopholia in the Northeast—Northeastern IPM Center
- Spotted Wing Drosophila—Cornell University
- Fruit Flies/Spotted Wing Drosophila Fact Sheets and Seasonal Update—University of Maine Cooperative Extension
- Spotted Wing Drosophila—Maine Organic Farmers and Gardeners Association
- Spotted Wing Drosophila Information—Michigan State University Integated Pest Management
- Spotted Wing Drosophila Information—UMass Amherst Fruit Advisor
- Berries and Biocontrol Presentation (PDF)—Maine Department of Agriculture, Conservation & Forestry
[Photos: Hannah Burrack, North Carolina State University, Bugwood.org; © Queen's Printer for Ontario, 2011; Hannah Burrack, North Carolina State University, Bugwood.org]