Spotted Wing Drosophila

SWD male''  Wisconsin  Minnesota 

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

Weekly reports for 2018

  • July 31 SWD report - Cooler weather means more SWD activity; blueberry and other berry crops must be protected against infestation.
  • July 24 SWD report - Spotted wing Drosophila catches are continuing. Keep protecting fruit through harvest season.
  • July 17 SWD report - Levels of SWD in traps continue to rise in southern Michigan, are leveling off mid-state, and dipping a bit in the north.
  • July 10 SWD report - Cooler weather last week coincided with a big jump in the number of SWD caught in traps; ripening fruit must be protected against infestation.
  • July 3 SWD report - SWD are still active, though traps caught low numbers due to the heat; ripening fruit must be protected against infestation.
  • June 26 SWD report - Monitoring traps are detecting increasing fly activity as fruit continue to ripen.
  • June 19 SWD report - It’s a much later season for spotted wing Drosophila in 2018. Recent monitoring shows how this pest can vary from year to year.

Key articles from 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.

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