Spotted Wing Drosophila
by Mira Danilovich, WVU Extension Service Consumer Horticulture Specialist and
Daniel Frank, WVU Extension Service Entomology Specialist
Spotted winged drosophila (Drosophila suzukii) is one of the most recent additions to the list of the invasive species. It does not discriminate against any fruits, vegetables, and/or ornamentals that have soft skin presenting an easy target for gravid females to deposit their eggs. Among its favorites on the menu are peaches, nectarines, plums, cherries, strawberries, grapes, blueberries, raspberries, blackberries, cranberries, currents, gooseberries, tomatoes, saskatoons, mulberries, and elderberries.
It is native to Southeast Asia and is a common pest in Japan, China, Russia, Korea, India, Myanmar, and Thailand. In the United States, it was first discovered in Hawaii in early 1980 and has been established there since 1986. California reported its first SWD encounter in 2008. Since then, SWD has been rapidly expanding its distribution range. It can be found up and down the east coast from Florida to Maine. It was first identified in West Virginia in 2011.
DescriptionThe adult flies are only 2 to 3 mm long, have a yellow-brown body, and very big red eyes. The males have a dark spot at the edge of each forewing and two dark bands on the forelegs. Females do not have these markings; they have very distinctive serrated specialized organ for depositing eggs capable of slitting through the undamaged fruit skin.
Damaged fruit becomes soft, appears bruised, collapses on itself, and often there is ooze associated with the punctures that facilitate fungal development. Fruit with maggots becomes unusable and unsellable. In essence, the crop is ruined.