Keep a Compound Eye Out for Spotted Wing Drosophila

Posted: March 28, 2011

Years ago, we knew the Brown Marmorated Stink Bug was out there – but it still took us by surprise. Dr. Ed Rajotte, Penn State Professor of Entomology and IPM Coordinator, advises growers to not make the same mistake with the Spotted Wing Drosophila, Drosophila suzukii.

Spotted Wing Drosophila is an insect pest of most berries, cherries, grapes, and other tree fruit with soft flesh. First discovered in the western U.S. in 2008, SWD moved on to areas of Florida, Michigan, and North Carolina by 2010. 

Females damage fruit by slicing through the skin with their knife-like ovipositor, inserting eggs that develop into small white larvae. These cuts can also be a pathway for fungal pathogens, leading to greater reductions in fruit quality. The SWD may affect more harvestable fruit than native Drosophila species that typically only lay eggs on already-damaged fruit. Infested fruit will not show obvious symptoms until a few days after egg-laying, when the fruit flesh starts to break down.

For information on monitoring, identification, and control of Spotted Wing Drosophila, consult the North Central IPM Regional Pest Alert fact sheet at