Spotted wing drosophila adult with red eyes

Spotted-wing drosophila (Drosophila suzukii)
Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org

Updated: March 9, 2021

Small worms in fruit

  • May is the time to look for spotted wing drosophila (SWD), a  pest of fruit plants in Maryland. Jerry Brust, Ph.D., Extension Vegetable Specialist gives you the details and photos in his information on spotted wing drosophila. Two popular backyard fruit crops, blackberry, and raspberry, are favorite host plants for SWD. They will also damage cherries, blueberries, other tree fruits.
  • The spotted wing drosophila (SWD), Drosophila suzukii, is a small vinegar fly with the potential to damage many fruit crops. In the North Central region, it was first detected in Michigan in late September 2010. Unlike most other vinegar flies that require damaged fruit to attack, SWD causes damage when the female flies cut a slit and lay eggs in healthy fruit. 
  • Make your own simple trap to monitor for this destructive fruit fly by following these instructions from Oregon State. The trap consists of a clear plastic drink cup and apple cider vinegar. The yellow sticky cards make it easier to attract and identify SWD. There are many online suppliers of yellow sticky cards. You can also use the trap without the cards.
comparison of male and female spottedwing drosophila
Fig. 1 comparison of male and female SWD
Fig. 2 Examples of damage

Damage caused by spotted wing drosophila (SWD)

  • The pest attacks healthy, ripening fruit as well as damaged or rotting fruit. The serrated ovipositor of the female (small fly) allows her to penetrate fruit and lay eggs just under the skin, causing a depression, dimple, or puncture that can easily be seen in many smooth-skinned tree and small fruits.