Issue 17, September 24, 2012

Spotted Wing Drosophila

Over the summer and especially the last few weeks, detections of spotted wing Drosophila, Drosophila suzukii, and reports of larval damage to fruit have been increasing in Illinois and nearby states including Iowa, Wisconsin, and Minnesota. Infestations have posed problems in Michigan since 2010. In Illinois, the list of counties where this is insect has been collected include Pope, Union, and Marion in the southern part of the state, Champaign, Tazewell, and Adams in the central part of the state, and Ogle County in the north. It likely is present in most if not all of the counties in Illinois.

Spotted wing Drosophila is a destructive pest of thin-skinned fruits because unlike other Drosophila species, it lays eggs into ripening fruit before it's ready for harvest. Infested fruits "melt down" from larval feeding in just a few days. Adult flies are tan and 2-3 millimeters long (up to one-eighth inch long), live for up to 2 weeks, and females can lay up to 300 eggs. Development from egg to adult can occur in in little as 8 days, and 10 or more generations may develop within a season.

Spotted wing Drosophila larvae

It is likely that reports of this insect being found in Illinois will be reported by various mass media outlets. Clientele will ask landscapers and garden center personnel about this insect. Although it is likely to become a problem in berries, grapes, and tree fruits, it is not a pest of the ornamental landscape. (Rick Weinzierl, modified by Phil Nixon)

Phil Nixon

Return to table of contents