Hemlock woolly adelgid is a tiny, aphid-like insect from Asia that feeds on the sap of eastern hemlocks. Over several years, a heavy infestation can starve a hemlock of the stored energy it needs to grow, and the tree slowly declines. Cumberland County is entirely within Maine’s hemlock woolly adelgid quarantine.[1]
As of December 2024, the Maine Forest Service lists hemlock woolly adelgid as established in Yarmouth, and says it is widespread along the southern coast.[2]
Treatment options for hemlocks
How we treat hemlocks in Yarmouth
Systemic treatments rely on the tree to move them up into its branches. A hemlock with plenty of healthy foliage takes up treatment far better than one that is already in steep decline. Untreated infested hemlocks are likely to die within four to ten years.[4]
Why hemlocks matter
Eastern hemlocks are long-lived, shade-tolerant evergreens that provide year-round screening, shade streams and hold soil on slopes. Losing a mature hemlock changes a property, and replacing one takes decades.
Want the full picture? Read our complete guide to hemlock woolly adelgid treatment in Southern Maine.
Hemlocks and woods in Yarmouth
Hemlock Woolly Adelgid help near Yarmouth
Tree Medics is based in Biddeford and works throughout Southern Maine. We also offer hemlock woolly adelgid services in nearby towns:
See all tree care in Yarmouth.
Sources
- Maine DACF: Hemlock woolly adelgid quarantine counties and towns
- Maine Forest Service: Hemlock woolly adelgid overview and distribution
- Maine Forest Service: Hemlock woolly adelgid fact sheet
- Michigan Invasive Species Program: Plan to treat trees for hemlock woolly adelgid (2026)
- U.S. Census Bureau: QuickFacts, Yarmouth town, Cumberland County, Maine (2020 Census)
