June 18, 2025

The Minnesota Department of Agriculture (MDA) is preparing to aerially manage seven sites in Fillmore, Houston, and Winona counties to slow the spread of spongy moth. Officials will likely conduct the aerial management activities July 1-3, beginning as early as 6:30 a.m. and continuing throughout the day. These dates are dependent on weather conditions in the area.

This operation was originally scheduled for mid-June, however due to federal budget uncertainties and delays the operation was pushed back to early July. 

The seven sites total approximately 28,907 acres. Maps of the sites are available on the MDA website. Residents can also look up their address on an interactive map to determine if they are within any of these blocks. Two of the sites include Minnesota State Parks, Whitewater and Beaver Creek Valley. 

The MDA will use a method of mating disruption which is the aerial application of a non-toxic waxy, food-grade substance containing pheromones specific to spongy moths that confuse the male moths. This makes it difficult for the male spongy moths to find females, reducing mating success. The result is fewer caterpillars hatching and attacking trees next year. 

The mating disruption product will be applied by low-flying yellow planes contracted by the United States Department of Agriculture’s Forest Service in a joint project with the MDA. The product is not harmful to humans, animals, birds, or other insects, and will help protect forest health, property values, and the state’s tourism industry.

To help area citizens stay informed, the MDA has set up a Report a Pest Info Line at 1-888-545-6684 with the latest details about treatment dates and times. On the morning of the treatments, residents can call the phone number with any questions they may have. Simply press 0 (zero) to speak to someone. The MDA's website also has information about spongy moths and control efforts. 

Residents can also sign up for text or email updates about treatment progress. On the Spongy Moth Treatment Map you can click each area (outlined in blue) you would like to receive updates for, follow the “sign up for text or email notification” link. 

Spongy moths are among America's most destructive tree pests, having caused millions of dollars in damage to eastern forests. The moths are now threatening Minnesota. If present in large numbers, spongy moth caterpillars can defoliate large sections of forest. Oak, poplar, birch, and willow are among their preferred hosts. The moths spread slowly on their own, but people can unintentionally help them spread by transporting firewood or other items on which the moths have laid their eggs.

Contact the Minnesota Department of Agriculture at 1-888-545-6684 or reportapest@state.mn.us with questions regarding spongy moth and the planned treatment.

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Media Contact
Brittany Raveill, MDA Communications
651-201-6131
Brittany.Raveill@state.mn.us