Invasive Forest Insect Pests in Maine

Click here to download the above image as a pdf.

*Please note: The poster states that emerald ash borer is not in Maine; however, since publication it has been found in Maine.

Maine Soil & Water Conservation Districts received a grant from the Maine Department of Agriculture, Forestry and Conservation (DACF) to present programs for the Invasive Forest Pest Outreach Project- as well as displays at fairs and other events – throughout the state in 2017.


Since 2009, with funds provided in part by a grant from the USDA Animal Plant Health Inspection Service (APHIS), Maine DACF has been educating Maine citizens about invasive pests. Maine conservation districts are now taking up that outreach to educate the public and municipalities about the threats of non-native forest pests:

Those that occur in Maine include:

  • emerald ash borer, recently found in Madawaska and York County
  • hemlock woolly adelgid & elongate hemlock scale, recently found near Waldo County
  • winter moth
  • gypsy moth
  • browntail moth *Browntail moth caterpillars defoliate trees; contact with toxic hairs can cause severe dermatitis and respiratory problems.

Those that do not YET occur in Maine, but are close by in NH and MA:

  • Asian longhorned beetle

Emerald Ash Borer

The Emerald ash borer was discovered in Maine for the first time in May of this year. Emerald ash borer is an invasive insect that has killed millions of ash trees across the Eastern US. In areas where it is established, ash trees are generally completely wiped out. Ash tree species are an important component of Maine forests, providing lumber and other wood products, wildlife food, and materials for First Nations basket makers.

Here are two good publications from the Maine Forest Service on what landowners, foresters and loggers should know about managing and planning for this serious pest:

Not at all familiar with the EAB issue? See our introductory article

Basic Signs and Symptoms of Emerald Ash Borer (colorful poster)

Other Information on Managing EAB Infestations

Info for Maine Land Owners

Info for Maine Forest Managers

EAB Decision Guide for Landowners

Managing EAB infestations

A Checklist for Municipalities

Emerald Ash Borer Information Network


Hemlock Woolly Adelgid

The hemlock woolly adelgid is in Maine and has nearly reached or may have reached Waldo County. WCSW currently has initiated a volunteer monitoring program to look for HWA called Take a Stand. With potential biocontrols (predators that eat HWA that can be released in Maine) in development, finding this pest early may allow us to save hemlock trees. WCSW can provide assistance to county landowners, including land trusts and municipalities, in planning for and managing  HWA infestation. Please contact us for more information.

Recognizing hemlock woolly adelgid

An informative film on HWA

Maine DACF information on HWA


Browntail Moth

Browntail moth is an invasive forest pest that continues to expand its range in Maine bringing with it human health impacts. Browntail moth is now present in Waldo County and other areas of the Midcoast. The larval stage (caterpillar) of this insect feeds on the foliage of hardwood trees and shrubs including:  oak, shadbush, apple, cherry, beach plum, and rugosa rose.  Larval feeding causes reduction of growth and occasional kills valued trees and shrubs.  While feeding damage may cause some concern,  the primary concern is the impact on humans from the  browntail moth is the result of contact with poisonous hairs found on the caterpillars.  Contact of these hairs with human skin causes a rash similar to poison ivy that can be severe on some individuals, and the hairs can cause breathing problems.  Late winter is an ideal time to control it by clipping and destroying its winter webs.

Skin rash from browntail moth

See the Maine Forest Service website for an overview of its biology, history in Maine and updates on current browntail range/ areas at risk. MFS also has information about management options and ways to mitigate human health impacts. If you think you have browntail moth infestation on your property in Waldo County, please inform the District or the Maine Forest Service.

How do invasive pests get here?

Forest pests typically get moved around unintentionally. They get moved long distances:

  • in wooden packing material (pallets and crates);
  • on infested plants in the nursery trade;
  • in soil of plants that people bring to summer homes or when they move.
  • (browntail moth) on vehicles that were parked in infested areas

Buy it where you burn it!

One major vector for the movement of forest pests over long distances is FIREWOOD.

Maine currently bans bringing out of state firewood across state lines, but you can just as easily transport pests from one part of the state to another.

To help folks find local campwood and firewood, Maine has joined Firewood Scout.

At Firewood Scout, you can find local firewood, sell your local firewood (under “About Us”), and reduce the movement of invasive pests.

To learn more about invasive forest pests, attend a presentation in your area!


Forest Pest Programs

These programs are designed to help landowners and users, landscape and forest professionals, and all residents of the state to

  • identify current and potential invasive forest pests and their host species,
  • understand the threats to our forests and woodlands posed by these pests, and
  • learn how to report suspected pest sightings or damage to trees that may be a result of pest infestations

Waldo County SWCD Programs

Take a Stand

  • Help us monitor for hemlock woolly adelgid in Waldo County through our Take a Stand program. Contact us to learn more or to request a presentation on forest pests.

Free Presentations

  • Introduction to Forest Pests in Maine
  • Emerald Ash Borer preparedness
  • Browntail Moth
  • Hemlocks and Hemlock Woolly Adelgid
  • All participants receive an information packet with fact sheets about the major pest species, a list of host trees that the species may be found on, and other relevant information.
  • All workshops are free
  • Recertification credits These programs are reviewed and may be approved for the following recertification credits (depending on lenght of program):
    • Professional CFE credits by the Society of American Foresters. Category 1-CF: 2.0
    • Pesticide Applicator credits by the Board of Pesticides Control: 2.0

 If you would like to attend a presentation in your area, or would like us to present in your town or for your organization, please contact us.

Upcoming Events

Watch this space for 2019 forest pest events to be offered.

For more information and fact sheets about invasive forest pests:

To report a suspected sighting of an invasive pest, contact or (207) 287-2431.

To find local firewood or campwood, visit Firewood Scout at


This material is made possible through a grant from the Maine Department of Agriculture, Conservation & Forestry and is funded in part by a Cooperative Agreement from the United States Department of Agriculture Animal and Plant Health Inspection Service (APHIS). The USDA and DACF are equal opportunity providers and employers. Some content provided by Knox-Lincoln Soil and Water Conservation District.