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July 10, 2024

The Minnesota Department of Agriculture (MDA) is preparing to treat six sites in central and northern St. Louis County to slow the spread of spongy moth. Officials will conduct the aerial management activities the starting July 11 beginning as early as 6:30 a.m. each day and continuing throughout the day. The dates are dependent on weather conditions in the area and will take several days.

Treatments will take place in the cities of Hibbing, Mountain Iron, and Virginia as well as three rural areas in the county. There are maps of the sites 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.

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 spongy moths to find females for mating, reducing mating success. The result is fewer caterpillars hatching and attacking trees next year. Application is timed just as adult moths emerge 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. 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-MOTH 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 updates about treatment progress:

  • Text “MNMDA NORTH” to 66468 to receive text notifications.
  • Text “MNMDA NORTH” [your email address here]” to 66468 to receive email notifications.

Or sign up online for text or 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 with questions regarding spongy moth and the planned treatment.


Media Contact
Brittany Raveill, MDA Communications