Emerald Ash Borer 101: Identification, Damage and Management Tips

What is Emerald Ash Borer? 

Emerald Ash Borer (EAB) is an invasive wood boring beetle native to Asia that poses a serious  threat to Ash trees across North America. First detected in Maine in 2018 this destructive pest has  already caused the death of 10s of millions of Ash trees across 37 U.S. states. The adult EAB is a  striking metallic green beetle with a reddish- coppery belly measuring up to 1.5 inches long. Female  beetles can lay 40 to 200 eggs in bark crevices. These eggs hatch in about two weeks, and the larvae  Burrow into the tree, living for about three weeks, before the process starts again.  

Inside, they feed on the cambium and phloem, forming S shaped galleries that block the tree’s ability  to transport nutrients. This eventually girdles the tree and can cause death within just a few years. Girdling is the process in which the EAB feeds around the tree cutting off the flow of water and  nutrients between the roots and canopy. In weakened trees leading to Ash snap- a structural failure  of limbs or the trunk. 

Emerald Ash Borer’s are most active during warm summer days. During storms or cool weather, they retreat into  bark crevices or hide beneath the foliage. Because they’re hard to spot in early stages, infestation  often goes unnoticed until significant damage has already occurred. In April 2025, EAB was  confirmed as a well-established aggregation, on Mount Desert Island. Just 70 miles from our  location in the Midcoast. It’s only a matter of time before they move inland.  

EAB naturally moves at a slow rate- about one mile per year. However human activity can drastically  speed up their spread. Transporting infested wood, nursery stock, or untreated wood products are some of the most common ways they reach new areas. There is a quarantine now in place for this  zone, however with summer approaching wood is sure to be moved.  

Signs of Emerald Ash Borer

• Early detection is critical. Keep an eye out for these warning signs. If you notice multiple signs on a  single Ash tree, it’s time to act. 
• Excessive woodpecker activity (they feed on larvae) 
• Thinning canopy or upper branch dye back. 
• Vertical bark splits. 
• S-shaped galleries beneath the bark. 
• D-shaped exit holes on the trunk. 
• Sprouts from the base (epicormic shoots).

Emerald Ash Borer Prevention & Management  

1. Create a Trap Tree 

• One natural method of slowing the spread is to create a trap tree using girdling, most effective in the  late spring to early summer: 
• Select a healthy Ash tree in a non-critical location. 
• Strip an 8-10 inch ring of bark from the lower trunk, ensuring a clean cut around the entire  circumference. 
• Make sure you remove the bark down to the sapwood.  
• The tree will eventually die, but it will attract EAB adults, reducing pressure on nearby trees. You  must remove and destroy the trap tree before larvae mature and emerge. 

2. Organic Tree Injections 

At Main Treekeepers, we offer an organic, targeted treatment using the Eco-Ject Microinjection  System. Ideal for urban and residential settings, this method minimizes environmental impact while  effectively treating pests from the inside out. 

This process is where we inject TreeAzin, a systematic insecticide derived from Neem tree seed  extract, directly into the tree’s vascular system. As the tree photosynthesizes, the treatment moves  into the canopy- eliminating EAB without harming beneficial insects, pollinators, or surrounding  plants. This is a safe, effective solution to protect your most valuable Ash trees. Most effective  during the late spring and early summer when adult beetles are active and seeking hosts.

3. Aphinity Traps with Pheromones 

The last effective tool to fight against EAB is the Aphinity trap- a specially designed device that lures  adult male beetles using pheromones. These traps are typically green prism shaped structures coated  with sticky sides and hung high in Ash trees on a stable limb. The trap releases a synthetic  pheromone that mimics the chemical signals of a distressed tree, making the beetles believe the tree  is a suitable host. While the traps won’t eliminate an infestation of their own, they are valuable for  monitoring beetle activity, identifying the presence of EAB and reducing local population. Most  effective during the late spring and early summer when adult beetles are active in seeking hosts. 

Protect your Trees with Maine Treekeepers 

At Maine Treekeepers, we recommend using any of these methods to help mitigate the inevitable  destruction of our Ash trees. We offer tree health assessment, organic treatment plans, and tree  preservation services rooted in ecological care. Contact us today to schedule an EAB inspection or  learn more about treatment options. 

What You Can Do to Stop Emerald Ash Borer

• Inspect your Ash trees regularly.
• Do not move firewood or wood products from infested and quarantined areas.
• Do not prune or trim your Ash trees.
• Create trap trees to monitor and reduce EAB activity.
• Schedule an organic injection treatment for high value Ash trees.
• Report EAB sightings to local forestry officials

SAVING THE EARTH, ONE TREE AT ATIME