Minnesota State Wire

The Minnesota Department of Agriculture (MDA) is initiating a quarantine for areas infested with spongy moths in Coon Rapids, Grand Rapids, and Winona. Starting on May 1, a portion of each city will be under quarantine, restricting the movement of woody material from the specified areas.

Residents can find a detailed map of the quarantined zones on the MDA website. These restrictions will last until June 15, 2026.

The quarantine will limit the movement of trees, branches, and other woody materials, including firewood, from these areas. While trees can be pruned, the branches must remain on the property, as even chipped branches can still harbor viable spongy moth eggs. Additionally, residents must inspect any equipment, household items, or vehicles left outside within the quarantine area before moving them outside. Items such as wood pallets, patio furniture, grills, campers, and boats require attention. Spongy moth egg masses, which are tan and fuzzy and roughly the size of a quarter, should be scraped off or left in place.

High levels of spongy moths were discovered in Coon Rapids and Grand Rapids during the 2024 annual survey conducted by the MDA. The infestation in Winona was identified by employees at a city campground. Initial plans to manage these areas with Bacillus thuringiensis var. kurstaki (Btk), an insecticide for controlling spongy moth caterpillars, were canceled due to federal funding delays and uncertainties.

Spongy moths have caused extensive forest damage in the eastern United States and pose a threat to Minnesota, where they can defoliate extensive areas of urban and natural forests. The moths feed on over 300 tree and shrub species, including oak, aspen, basswood, and birch, which are common in Minnesota.

To provide more information, the MDA will host two informational meetings. These will be held virtually on Wednesday, April 30, from 4:30 to 6:30 p.m., and Tuesday, April 29, from noon to 1 p.m.

The MDA will also increase survey efforts in the affected areas, and residents may notice traps placed on trees. The department urges residents to report any signs of spongy moths using the MDA's Report a Pest service online, via email at reportapest@state.mn.us, or by phone at 1-888-545-6684.