The Minnesota Department of Agriculture (MDA) had initially planned to manage 12 areas of the state affected by the spongy moth using Bacillus thuringiensis var. kurstaki (Btk), a bacterial insecticide. However, the lack of timely federal funding has led to the cancellation of these plans. The spongy moth, a significant invasive pest, poses a threat to the health of forests. In order to be effective against the pest’s lifecycle, the application of Btk needs precise timing in the spring.
Without the necessary funds, MDA abandoned the proposed aerial management in areas covering 2,752 acres, including parts of Anoka, Carlton, Itasca, St. Louis, and Winona counties, as well as the cities of Coon Rapids, Grand Rapids, and Winona. MDA Commissioner Thom Petersen expressed concern: “Having to cancel Btk aerial management operations in these areas jeopardizes the future success of this program. Spongy moth populations in these areas will likely increase and advance quicker into neighboring areas, making future years of management more complicated and costly.”
Historically, the MDA, alongside the United States Department of Agriculture (USDA) Forest Service’s Slow the Spread program, has successfully reduced the spongy moth’s spread by more than 60% across over 1.1 million managed acres in Minnesota.
In response to the cancellations, the MDA may consider temporary quarantines to prevent the human-assisted spread of the moth’s life stages or woody materials across the state. Nonetheless, the department remains committed to controlling the population, proposing to manage 112,000 acres with an aerially applied mating disruption pheromone that prevents moth reproduction. This action, along with their annual survey tracking moth populations, also depends on federal funding. While initial funding for the moth survey is confirmed, it remains uncertain if the aerial mating disruption funds will be allocated in 2025.
The MDA emphasizes the importance of managing spongy moth populations, highlighting the economic impact and risk they pose to Minnesota’s forests, livelihoods, and state economy.
