Cumberland · Cumberland County

Hemlock Woolly Adelgid Treatment in Cumberland, ME

Protect Cumberland’s hemlocks from hemlock woolly adelgid with inspection and systemic treatment from Tree Medics, based in Biddeford.

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Inspecting a hemlock branch for woolly adelgid
CountyCumberland County
HWA in CumberlandEstablished
Check twigsTwice a year
One treatment can last4+ years

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]

Hemlock woolly adelgid in Cumberland

As of December 2024, the Maine Forest Service lists hemlock woolly adelgid as established in Cumberland, and says it is widespread along the southern coast.[2]

Treatment options for hemlocks

Long-lastingImidaclopridFor hemlocks under three feet in diameter, one soil application can keep adelgid below damaging levels for more than four years.[3] It moves slowly, taking a year or more to reach the top of a large tree.[4]
Fast-actingDinotefuranMoves through the tree faster, which makes it useful for heavily infested hemlocks, but protects for only one to two years.[4]
Small treesOil and soapHorticultural oil and insecticidal soap can work on small trees, but need thorough coverage once or twice a year.[3]

How we treat hemlocks in Cumberland

Step 1InspectWe check the underside of branches for adelgid and judge how much healthy foliage the tree still has.
Step 2Choose the right treatmentHeavily infested trees may need fast-acting treatment first, while healthier trees can get long-lasting protection.
Step 3MonitorWe keep an eye on treated hemlocks so they can be retreated when needed.
Hemlocks respond best when treated early.

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 Cumberland

Hemlock woolly adelgidA 2021 forest management plan for Knight’s Pond Preserve found that hemlock makes up about 21% of the stand’s basal area and noted the nearest known hemlock woolly adelgid population on Harris Road in Cumberland.[5]
Local landscapeKnight’s Pond Preserve, shared by Cumberland and North Yarmouth, includes a 46-acre pond and a roughly 14-acre preservation area set aside for its shagbark hickory and oak stand.[6]

Hemlock Woolly Adelgid help near Cumberland

Tree Medics is based in Biddeford and works throughout Southern Maine. We also offer hemlock woolly adelgid services in nearby towns:

Falmouth, MEYarmouth, MEFreeport, MEPortland, ME

See all tree care in Cumberland.

Sources

  1. Maine DACF: Hemlock woolly adelgid quarantine counties and towns
  2. Maine Forest Service: Hemlock woolly adelgid overview and distribution
  3. Maine Forest Service: Hemlock woolly adelgid fact sheet
  4. Michigan Invasive Species Program: Plan to treat trees for hemlock woolly adelgid (2026)
  5. Town of Cumberland: Knight’s Pond Preserve Forest Management Plan (2021)
  6. Town of Cumberland: Subcommittee – Forestry (2024)
FAQ

Hemlock Woolly Adelgid in Cumberland: common questions

Is hemlock woolly adelgid in Cumberland?

Yes. As of December 2024, the Maine Forest Service lists hemlock woolly adelgid as established in Cumberland.

How long does hemlock treatment last?

For hemlocks under three feet in diameter, one imidacloprid soil application can keep adelgid below damaging levels for more than four years. Dinotefuran works faster but lasts one to two years.

How long does treatment take to work?

Imidacloprid moves slowly and can take a year or more to reach the top of a large tree. Dinotefuran moves faster and is often used on heavily infested trees.

Is Cumberland in Maine’s hemlock woolly adelgid quarantine?

Yes. All of Cumberland County is within Maine’s hemlock woolly adelgid quarantine, which restricts moving hemlock material.

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Worried about a tree?

Many tree health problems can be managed when they are caught early. Reach out today for a professional evaluation.

(207) 303-7291 SaveMyTrees@TreeMedics.com

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