Forest pests and disease can cause significant damage to trees and, in the case of ticks, can be a threat to human health. They require monitoring and management to slow their impact. There are several resources available to help homeowners, municipalities, and forest land owners and managers address pests and disease, thereby preserving the overall health of Maine's forest resources. This page includes just a few of the higher priority species that are the largest threat to Maine’s forest health and updates about their spread and alerts from the State of Maine.
Those looking for more information about forest pests and disease should visit the Maine Forest Service webpage: Invasive Threats to Maine’s Forest and Trees.
WATCH: EAB Monitoring for Landowners with Forest Entomologist, Colleen Teerling.
Adult emerald ash borer.
Emerald ash borer signs.
Browntail Moth Update - March 15, 2022
Emerald Ash Borer
The EAB quarantine area was updated in November 2023 and now includes all of Androscoggin, Cumberland, Kennebec, Knox, Lincoln, Sagadahoc, Waldo and York Counties and parts of Aroostook, Franklin, Oxford Penobscot, Piscataquis, and Somerset Counties.
The emerald ash borer (EAB), Agrilus planipennis, is one of the most serious invasive species threatening our ash resources and forests. All species of ash trees (Fraxinus), but not mountain ash (Sorbus), that grow in Maine are susceptible to injury and death by the emerald ash borer.
EAB was first found in Aroostook County (Madawaska, Frenchville, and Grand Isle), and York County (Acton, Berwick, and Lebanon) in 2018. It was detected in Cumberland County (Portland) in September 2019, and Oxford County in March 2021. As of June 2022 EAB has been detected in Waterville, Oakland, Lewiston, Gray, and Lovell.
"This is not the time to throw in the towel on the EAB quarantine in Maine. Maine Woodland Owner members and landowners like them are among the people who will be most impacted by the faster spread of emerald ash borer if a quarantine on the pest is not continued," said Executive Director of Maine Woodland Owners Tom Doak. "I recognize a quarantine does not prevent the spread of this pest, but it does slow it down. With the time bought, ash already on woodlots will increase in value, and landowners will have more options for management before the insect arrives."
How to Create a Trap Tree to Monitor for Emerald Ash Borer
Maine’s Native Ash Trees and the Emerald Ash Borer - Landowner Survey
MFS Emerald Ash Borer Information Sheet
Visit www.maine.gov/eab for more information
From July 2018 edition of Maine Woodlands Emerald Ash Borer Now Found in Maine
Read the 8/30/21 press release from Maine Department of Agriculture, Conservation, and Forestry
Read the 3/29/21 press release from Maine Department of Agriculture, Conservation, and Forestry:
Read the 1/6/21 press release from Maine Department of Agriculture, Conservation, and Forestry:
Browntail Moth
The browntail moth (Euproctis chrysorrhoea) is an invasive species found only on the coast of Maine and Cape Cod and impacts the health of forests and humans.
Browntail moth have tiny poisonous hairs that cause dermatitis similar to poison ivy on sensitive individuals. People may develop dermatitis from direct contact with the caterpillar or indirectly from contact with airborne hairs. The hairs become airborne from either being dislodged from the living or dead caterpillar or they come from cast skins with the caterpillar molts. Most people affected by the hairs develop a localized rash that will last for a few hours up to several days but on some sensitive individuals the rash can be severe and last for several weeks. The rash results from both a chemical reaction to a toxin in the hairs and a physical irritation as the barbed hairs become embedded in the skin. Respiratory distress from inhaling the hairs can be serious.
Blacklegged Ticks
There are three ticks primarily found in Maine. The blacklegged tick is the most common and causes the most health rist. The tick’s scientific name is Ixodes scapularus (dammini) and its official common name is blacklegged tick, but it is familiarly known as the deer tick, because of its preferred adult-stage host (the animal on which the adult tick typically lives). These ticks become vectors when they, as larvae and nymphs, feed on mice, chipmunks, red squirrels and other small mammals that are reservoirs of several agents that cause diseases in human and domestic animals.
Here are links to important resources that help identify, protect you from, and understand the blacklegged tick:
NEW: Maine Forest Tick Survey 2021 Results Summary
From the journal EcoHealth: Active Forest Management Reduces Blacklegged Tick and Tick-Borne Pathogen Exposure Risk
Maine Forest Tick Survey - Become a citizen scientist and help collect ticks in your woodland to help further research about ticks in Maine’s forests.
University of Maine Cooperative Extension Tick Lab - Submit ticks found on your property for analysis and to contribute to ongoing research
Maine Medical Center Research Institute - Find out the latest human health implications from ticks and best ways to prevent illness.
Maine Woodland Owners Tick Prevention Products - these handy tools to prevent and remove ticks are a necessary item for anyone who spends time in the woods.
Hemlock Woolly Adelgid
The hemlock woolly adelgid is an invasive aphid-like insect that feeds on hemlocks. Feeding damage leads to decline and can cause mortality of affected trees.
Managing Hemlock by Oliver Markewicz
Hemlock Woolly Adelgid Information from Maine Forest Service