*This page will be actively updated during the treatment window for SBW (predicted to be between May 20 and June 25, 2025).
Background
The Maine Budworm Response Coalition (MBRC), comprised of timberland owners and managers in Maine, successfully advocated for emergency funding to oversee and implement the Early Intervention Strategy (EIS) methods to reduce the rising SBW populations and protect the health of our forest ecosystems and resources, maintain wildlife habitat, and prevent impacts to our forest-based economy. The MBRC is collaborating with the Maine Forest Service (MFS), who will provide technical assistance and communications with landowners and the public regarding biology, management options, and SBW history. Additionally, the MFS will provide financial oversight and reimbursement for the state and federal funds supporting the SBW response.
MFS is working with landowners, scientists, the University of Maine, and other agencies to inform the MBRC where treatment is needed and how to best target those areas to reduce SBW populations below the outbreak threshold. To achieve this goal, the MBRC will be coordinating the administration of low-toxicity insecticides through an aerial spray program between May 20 and June 25. Roughly 240,000 acres in northern Maine with larval populations at or exceeding the outbreak threshold will be targeted.
Where is the 2025 Aerial Spray Program Happening?
The MBRC is planning aerial applications in the Aroostook County towns of: Allagash, Big Twenty Twp., New Canada, St. John Plt., T11 R15, T13 R15, T13 R16, T14 R11, T14 R12, T14 R14, T14 R15, T14 R16, T15 R10, T15 R11, T15 R12, T15 R13, T15 R14, T15 R15, T16 R12, T16 R13, T16 R14, T16 R5, T17 R12, T17 R13, T17 R14, T17 R4, T17 R5, T18 R10 T18 R11, T18 R12, T18 R13, T19 R11, T19 R12, and Wallagrass.
The treatment window, coinciding with ideal budworm and tree development, is predicted to be between May 20 and June 25, 2025.

Aerial spraying will only be applied:
- Inside predetermined areas of spruce-fir forest with SBW populations that are at or above the action threshold
- No closer than 100 ft from lakes, streams, other bodies of water and ¼ mile from identified habitat of state-endangered and threatened butterflies
- In good weather (no rain or high winds) to prevent drift or unintended applications
- Using reduced-risk insecticides that only affect larvae that eat treated foliage
What Insecticides Will Be Used?
Insecticides containing active ingredients tebufenozide (Mimic) or Btk (Bacillus thuringiensis kurstaki, Foray) will be applied by helicopter and/or fixed wing aircraft using modern technologies to ensure accurate applications. SBW populations may require additional aerial applications over the coming years to ensure the populations do not reach an outbreak level.
To protect the public, road access in these areas will be temporarily blocked during active spray operations and until the spray application has dried – you may encounter roadblocks with the following signage. Please do not enter areas sooner than 4 hours after application.
