AgBioResearch scientist leads response team to address a potential new fruit pest in Michigan

Spotted wing drosophila, a small vinegar fly native to Asia, has been found in traps deployed this year by Michigan State University (MSU) entomologists in southwestern Michigan.

December 8, 2010 - Author: Holly Whetstone

Rufus Isaacs Inspecting Fruit Crop

Spotted wing drosophila (Drosophila suzukii), or SWD, a small vinegar fly native to Asia, has been found in traps deployed this year by Michigan State University (MSU) entomologists in southwestern Michigan. This pest is established in the western United States, damaging fruit in California and the Pacific Northwest, but this is the first time it has been found in the Midwest.

SWD is a pest of berry crops, cherries, grapes and tree fruit, with a preference for soft-fleshed fruit. No flies were trapped in Michigan through the summer months this year, but in late September and early October, monitoring traps in southwestern Michigan picked up male and female SWD. This pest has not been found in any fruit, and flies were trapped only after crop harvest was complete.

A Michigan SWD response team, chaired by MABR berry crops entomologist Rufus Isaacs, was formed earlier this year to survey the state's fruit industries and to develop a pre-emptive early detection-rapid response (ED-RR) plan as part of an integrated pest management (IPM) strategy for SWD. The response team is made up of entomologists from the MSU departments of Entomology and Horticulture, MSU Extension staff members, staff members from the Michigan Department of Agriculture (MDA) and fruit commodity group leaders.

Further monitoring will be done to determine the distribution of this fly in Michigan. Members of the SWD response team are urging fruit growers in the state to become aware of this pest and to plan for ED-RR through trapping, monitoring and crop-specific control measures as part of their IPM program for 2011.

"We have been aware of SWD since it was discovered in 2008 in California," Isaacs said. "This insect is originally from Asia but has already been found to be invasive in Hawaii, California, Oregon, Washington, Utah, Florida, the Carolinas and British Columbia."

"Early detection of an exotic pest is vital to our work to safeguard Michigan's agriculture producers and natural resources," said Ken Rauscher, director of the MDA Pesticide and Plant Pest Management Division. "Only through collaborative efforts with state, university and agricultural commodity leaders will we be successful in preserving the vitality of Michigan's fruit-growing industry."

Isaacs noted that if SWD is detected again next year, it will be one more insect pest that Michigan fruit growers will need to add to their crop management programs.

"IPM strategies will be implemented next year to help monitor and control SWD if it is discovered," he said. "The SWD response team is confident that Michigan growers can control this pest with proper management."

Educational presentations about SWD will be delivered at MSU Extension meetings for fruit growers this winter, including those at the Great Lakes Expo in Grand Rapids in early December. For more information, go to

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