SBW populations are increasing in northern Maine. The Maine Forest Service captured building SBW populations in northern Maine through surveys, where roughly 3,400 acres of defoliation was recorded during aerial survey in 2024. The University of Maine Spruce Budworm lab monitored SBW larvae (L2) on tree branch samples and found populations that were at or above the outbreak threshold of an average of seven larvae per branch in northern Maine. When larval populations are at or above this threshold, an outbreak of SBW is likely to occur.

Maine timberland owners and managers in Maine formed the Maine Budworm Response Coalition (MBRC) and are working collaboratively with the Maine Forest Service, Cooperative Forestry Research Unit, and Maine Forest Products Council to reduce impacts from SBW as it builds toward outbreak conditions. The MBRC successfully advocated for funding to implement Early Intervention Strategies (EIS), an approach developed and tested by New Brunswick, Canada to reduce SBW populations below the outbreak threshold.

More information on MBRC’s response to SBW can be found on the 2025 Aerial Spray Program page.