Spotted Winged Drosophila-1  Spotted Winged Drosophila-2 Spotted Winged Drosophila-2
Photo by: Gevork Arakelian, Ph.D.
Los Angeles County, Department
of Agricultural Commissioner/Weights
and Measures
Photo by: Elizabeth Beers,
Washington State University

Photo by: Hannah Burrack, North
Carolina State University

Spotted wing drosophila, a major fruit pest introduced from southeast Asia, has been discovered in North Dakota for the first time in 2013. Adult specimens were submitted to the NDSU Plant Diagnostic Lab from Carrington in Foster County and positively identified as SWD.

SWD was first detected in the continental U.S. in California in 2008 and has since spread to other fruit-producing regions of the country. SWD pierces seemingly healthy fruit, and lays its eggs. The eggs hatch in about 3 days and the larvae feed on the fruit. Early detection by gardeners and growers is critical because symptoms often do not appear until after the fruit is harvested and in the hands of the consumer. Commonly confused with the common fruit fly, Drosophila melanogaster, SWD differs as it attacks unripe to ripe fruit, whereas the common fruit fly feeds on overripe and rotting fruit. SWD most commonly affects raspberries, blackberries, strawberries, blueberries, honeyberries, grapes, hardy kiwi, cherries, plums, and peaches.

Treatments are available for SWD if detected early. Different chemical classes must be rotated, as the insect is capable of many generations in one growing season and may develop resistance.

It is impossible to identify SWD without adult specimens. If you believe you have found SWD, samples should be submitted to the North Dakota State University (NDSU) Plant Diagnostic Lab,

For more information and photos or how to create your own trap, visit these links.