Spotted Wing Drosophila

SWD male''  Wisconsin  Minnesota 

Welcome to our web resources on spotted wing Drosophila. This is a central location for information on this invasive pest, including links to regional resources from Wisconsin and Minnesota.

Weekly reports for 2017

  • Aug. 1 SWD report - Ripe and ripening fruit in susceptible crops must be protected. This is the final SWD report for the 2017 season.
  • July 25 SWD report - Trap catches continue to climb in all fruit producing regions. The summer surge is three to four weeks earlier than previous seasons. Ripe and ripening fruit in susceptible crops must be protected.
  • July 18 SWD report - Trap catches are sharply up in southwest, southeast, Fruit Ridge and west central Michigan. Ripe and ripening fruit in susceptible crops should be protected.
  • July 11 SWD report - Eighty percent of all SWD cup traps have captured SWD since the beginning of the season. Best practices for minimizing fruit infestation are reviewed. Start now!
  • June 27 SWD report - Another jump was seen in flies caught in monitoring traps. Ripening sweet and tart cherries and early ripening blueberry cultivars are vulnerable. Monitoring for this pest is critical as crops become susceptible.
  • June 21 SWD report - More spotted wing Drosophila have been caught in monitoring traps, with higher catches at minimally-managed sites in southwest Michigan. Monitor for this pest when crops become susceptible.
  • June 6 SWD report – Some traps in the network are already capturing SWD flies at low levels. Monitor for this pest when crops are starting to become susceptible.

Key articles from MSU and MSU Extension

Search for past reports and articles at MSU Extension’s Fruit & Nuts News.


The Spotted Wing Drosophila (SWD) is a vinegar fly of East Asian origin that can cause damage to many fruit crops. This small insect has been in Hawaii since the 1980s, was detected in California in 2008, spread through the West Coast in 2009, and was detected in Florida, Utah, the Carolinas, Wisconsin and Michigan for the first time in 2010. Because the flies are only a few millimeters long and cannot fly very far, natural dispersion between states is unlikely. Human-assisted transportation is a more likely cause of the recent rapid spread. It appears that this insect has become widely established through North America.

What crops are affected?

SWD has been detected in traps located near berry crops, grapes, cherries and other tree fruits. The flies have a preference for softer-fleshed fruit.

Status in Michigan

In fall 2010, SWD was detected in Michigan for the first time as part of a widespread Early Detection and Rapid Response program. SWD flies have now been detected in all of the counties where it has been monitored in the southern peninsula of Michigan, and we expect it to be present statewide. The activity period typically spans from early to mid-June through late fall.

What is being done?

A SWD Response Team has been formed that combines the expertise of MSU entomologists, horticulturalists, Extension educators, and Michigan Department of Agriculture staff. This website will be the central location for dissemination of information about this insect. Check back for updates. This team is also helping to coordinate research projects to understand how best to protect fruit from infestation by this new pest.

Managing SWD

We are confident the Integrated Pest Management (IPM) programs for SWD control can be implemented to enable continued harvest of high-quality crops. See our fact sheets for English and Spanish information on monitoring for this pest, and recommendations for managing SWD.

Important links

Funding for the SWD Response Team

The activities of the SWD Response Team are funded by Project GREEEN, the Michigan Department of Agriculture and Rural Development, US-EPAUSDA and Michigan grower organizations. A regional research and extension grant through the North Central IPM Center has also supported this website through a grant with the University of Wisconsin and University of Minnesota.

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.