As we enter the peak season for invasive insect activity, the Maine Department of Agriculture, Conservation and Forestry (DACF) and the United States Department of Agriculture (USDA) call on everyone to help protect our beloved trees. Throughout August, we encourage everyone to spend just a few minutes checking the trees in their communities and forests for signs of invasive species.

Help Matters

Invasive species, which include non-native plants, animals, and diseases, can cause significant harm to our environment, economy, and even human health. These invaders can wreak havoc without natural predators or diseases to keep them in check.

Maine State Horticulturist Gary Fish explains, “Our first defense against invasive species is to prevent their arrival in the first place. Our partners at USDA APHIS and Customs and Border Protection here in the US and the Canadian Food Inspection Agency north of the border frequently stop plant pests before they can gain a foothold in North America. However, the volume of trade and travel prevents them from stopping every pest.”

Maine State Forester Patty Cormier highlights the crucial role of public involvement: “Trees are vital to our state economy and provide countless environmental benefits, including clean air, water, wildlife habitat, and recreation opportunities. With more eyes on the ground, we can help detect invasive insects early, preventing tree loss and preserving our forests.”

Spotting the Threats – What to Look For

Watch for four primary invasive species:

• Asian longhorned beetle— This large (>1″) black and white beetle has a taste for maples and other hardwood or broad-leaved trees. Look for oval to round wounds on the bark where the females have chewed out a site to deposit eggs, round holes in the trunks and branches of trees, and piles of coarse sawdust at the base of trees.
• Emerald ash borer — This small (<1/2″) metallic green beetle is deadly for ash (Fraxinus) trees. Look for small (1/8″) D-shaped adult exit holes in the bark, winding frass-filled (sawdust-like waste) feeding galleries under the bark, woodpecker feeding, crown dieback, and epicormic shoots. Emerald ash borer has been found in Parts of Androscoggin, Cumberland, Kennebec, Oxford, Penobscot, and York Counties in the southern half of the state and northern Aroostook County.
• Oak wilt disease — This deadly fungal disease of oaks is found in other parts of the United States, including the closest known infestations in New York State. Look for leaves suddenly turning brown or dropping in the red oak group (pointed lobes on leaves) trees during summer months.
• Spotted lanternfly — This colorful planthopper, not known to be established in Maine yet, is an expert hitchhiker with a broad appetite. Spotted lanternfly feeds on and can damage various plants. It is best known for its impact on grapes and hops. Look for the brightly colored nymphs and adults, but be aware that this insect hitches a ride most subtly as dull-colored egg masses. Like the infamous spongy moth, the adult lays eggs on almost anything.
  
  For more detailed profiles on these and other threats, visit the Maine Forest Service website: maine.gov/forestpests.

What You Can Do

Please take 10 minutes and inspect the trees in our yards, neighborhoods, and local forests. If a suspected invasive pest is identified, take a picture and send it to foresthealth@maine.gov. Spotted lanternfly reports can be sent to bugwatch@maine.gov. Ensure photographs are detailed enough for verification—placing a coin or pencil next to the pest for scale can be helpful. If possible, capture the insect in a rigid container and store it in a cool place until you receive a response.

Prevent the Spread

Taking a few simple actions can make a big difference:

• Buy firewood where you’ll burn it or gather it on-site if permitted. Moving firewood can spread invasive pests.
• Check vehicles, bags, and boxes for insects when traveling locally or moving to a new area. Invasive insects can easily hitch a ride.

State Horticulturist Fish reminds us, “We all have a role to play in preventing the spread of invasive species. Taking a few minutes to check the trees in your yard can ensure that our forests and trees are here for future generations.”

We appreciate everyone’s dedication to protecting Maine’s trees and forests. Your vigilance and action are invaluable.

Images resources courtesy DACF

Asian longhorned beetle (ALB), Anoplophora glabripennis

Emerald Ash Borer (EAB), Agrilus planipennis

Oak wilt disease (Bretziella fagacearum)

Spotted lanternfly (Lycorma delicatula)