Quick Answer: Common emerald ash borer signs include a thinning canopy, dead upper branches, cracked bark, D-shaped exit holes, winding tunnels beneath the bark, increased woodpecker activity, and new shoots growing from the trunk. Because damaged ash trees can become brittle, have a declining tree checked before branches begin to fall.
What Is the Emerald Ash Borer?
The emerald ash borer is an invasive green beetle found throughout Indiana, including Muncie and Delaware County. It lays eggs in cracks in the bark of ash trees. After the eggs hatch, the larvae feed beneath the bark and damage the tissue that carries water and nutrients through the tree. As the damage spreads, branches die and the entire tree may eventually be lost.
Make Sure It Is an Ash Tree
Ash trees usually have leaves made of several smaller leaflets. Their leaves and branches often grow directly across from each other. Some trees with “ash” in their name are not true ash trees. Mountain ash, for example, is not affected by emerald ash borer. If you are unsure about the species, have the tree identified before assuming this insect is the cause.
Look for Canopy Thinning and Dead Branches
Damage often becomes visible near the top of the tree first. The canopy may look thin, uneven, or bare, and upper branches may begin to die. The decline can spread downward as the infestation gets worse. Drought, disease, and root damage can cause similar symptoms, so canopy loss should be considered with other warning signs.
Check for D-Shaped Exit Holes
Adult emerald ash borers leave small D-shaped holes when they exit the tree. Each hole has one flat side and one curved side. These holes can be difficult to find because they are small and may be high on the trunk or branches. Finding one on an ash tree is a strong warning sign, but not seeing one does not rule out an infestation.
Watch for Cracked Bark and Winding Tunnels
Long cracks may form in the bark as the tree becomes damaged. If loose bark falls away, winding S-shaped tunnels may be visible underneath. These tunnels were made by the larvae while feeding. Do not remove healthy bark to search for them because this can create another wound. An arborist can inspect the tree without causing unnecessary damage.
Notice Increased Woodpecker Activity
Woodpeckers often feed on emerald ash borer larvae beneath the bark. Their activity may leave pale or uneven patches where the darker outer bark has been removed. Woodpeckers also search for other insects, so their activity alone does not confirm emerald ash borer. It becomes more concerning when the tree also has canopy loss, bark cracks, or exit holes.
Look for New Shoots on the Trunk
A damaged ash tree may grow clusters of shoots from the trunk or near its base. This is a stress response as the upper canopy loses leaves and branches. The shoots may look green and healthy, but they do not necessarily mean the tree is recovering. New shoots combined with upper branch dieback may point to advanced decline.
Why Advanced Damage Is a Safety Concern
Ash trees damaged or killed by emerald ash borer can become brittle. Dead branches may break with little warning, and the trunk can become more difficult to remove safely. Do not climb a declining ash tree or try to cut large branches yourself. Keep people, pets, and vehicles away from dead or hanging limbs, especially if the tree is near a home, driveway, road, utility line, or neighboring property.
What Should You Do About a Declining Ash Tree?
The next step depends on the amount of canopy loss, the condition of the wood, and the tree’s location. An arborist can assess the tree and explain whether it should be monitored or removed. If the damage appears limited and you want to preserve the tree, ask a qualified plant health care provider whether treatment is still practical. Josh Newsome’s Tree Surgery can evaluate the tree’s condition and help plan safe removal when needed.
Frequently Asked Questions
Are emerald ash borers still a problem in Indiana?
Yes. Emerald ash borers have been found in every Indiana county. Ash trees that have not been protected can still become infested, and treated trees may need continued care.
How quickly can emerald ash borer kill a tree?
There is no exact timeline. The rate of decline depends on the tree’s health, size, and level of infestation. Early damage may remain hidden, while a heavily infested tree may decline much faster.
Does a D-shaped hole confirm emerald ash borer?
A D-shaped hole on a true ash tree is a strong warning sign. However, the tree species and other symptoms should also be checked before confirming the cause.
Can an infested ash tree recover?
A tree with limited damage may still have treatment options. Treatment cannot restore dead branches or badly weakened wood, so the tree should be evaluated as early as possible.
Can I remove a dead ash tree myself?
Dead ash trees can be brittle and unpredictable. Large branches may break while the tree is being cut. A large or badly damaged ash tree should be handled by trained professionals with the proper equipment.
Schedule an Ash Tree Assessment
Emerald ash borer damage can become harder and more dangerous to manage as the tree declines. Josh Newsome’s Tree Surgery provides ISA Certified Arborist-led assessments and removal planning in Muncie and surrounding Delaware County communities. Call (765) 378-8746 to schedule an ash tree assessment or request a free estimate.