July 12, 2023

The Minnesota Department of Agriculture (MDA) is preparing to treat one area in Carlton County and three areas in and around the city of Duluth to slow the spread of spongy moth (previously known as gypsy moth). Officials will conduct aerial treatments July 14, break for the weekend, and begin again on Monday July 17. Work will begin as early as 6:30 a.m. each morning and continue throughout the day. The dates and times depend on weather conditions in the area.

The treatment area in Carlton County is near Holyoke along the Wisconsin border, totaling approximately 14,000 acres. The three treatment areas around Duluth; Duluth East, Duluth West, and Midway total approximately 12,000 acres. Residents can look up their address on an interactive map to determine if they are within any of these blocks.

The MDA will use a method of mating disruption involving the aerial application of an organically certified, waxy, food-grade substance containing pheromones specific to spongy moths that confuses the male moths. This makes it difficult for the male moths to find females for mating, reducing mating success. This results in fewer caterpillars hatching and attacking trees next year. The application is timed just as adult moths are emerging in early summer.

The mating disruption product will be applied by low-flying yellow planes contracted by the U.S. Forest Service in a joint project with the MDA. These planes fly approximately 150 feet above the treetops and will be traveling outside the treatment areas as the planes navigate between the spongy moth treatment sites. 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 information line at 1-888-545-MOTH (6684). The hotline will offer the latest details about treatment dates and times. Residents can sign up for updates about treatment progress by texting “MNMDA MOTH” to 66468 to receive text notifications or texting “MNMDA MOTH [your email address here]” to 66468 to receive email notifications.

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 treatments.


Media Contact
Brittany Raveill, MDA Communications