Tree problems · Insect
Emerald ash borer: signs and what to do
Emerald ash borer is an insect pest, often seen on green ash, white ash. Look for: thinning or dying branches in the top of the crown, often starting in the upper part of the tree.
General information, not a diagnosis. A certified arborist or your county extension office can confirm.
- Insect
- Green ash
- White ash
- Other true ash trees
Signs to look for
Tick what you see. More ticks make it more likely, but only an on-site look can confirm.
0 of 6 signs ticked. Ticks stay in this browser only.
Season
Adult beetles fly in late spring and summer. The larvae feed under the bark and do their damage out of sight, so crown thinning often shows up a few years after the first attack.
How it spreads
Adults can fly short distances on their own. Most long jumps happen when people move firewood, logs or nursery stock from an infested area.
Where it is found
Emerald ash borer has been found across a large part of the eastern and central United States and in some western areas. Check your state official map; ranges change.
Official sources
What to do
- 1
Look closely at your ash trees for the signs above. Take clear photos of the bark and the crown.
- 2
Confirm the tree is an ash. Many trees with similar leaves are not ash.
- 3
Contact your county extension office or state department of agriculture to report and confirm a suspected case.
- 4
Ask a certified arborist whether the tree is worth protecting with a trunk or soil treatment, or whether removal is the safer plan.
- 5
If a tree is already badly declined, plan its removal before it gets brittle, because dead ash wood can break without warning.
- 6
Do not move firewood or logs from ash trees to other areas.
Safety first: do not climb, do not cut near power lines and do not use a chainsaw on storm-loaded wood. Call the utility for downed lines and 911 if anyone is in danger.
Prevention
Buy firewood where you will burn it and do not carry it between regions. A certified arborist can discuss preventive treatments for healthy, high-value ash trees. Treatments usually need to be repeated, so ask about the full cost over the years before you decide. When you replant, choose a mix of species so one pest cannot take out a whole street or yard.
When to call a pro
Call a certified arborist if an ash tree is thinning, has bark damage, or stands near a house, driveway, play area or power line. Dead ash trees become brittle, so removal near targets is work for a trained and insured crew with proper equipment.
Not sure who to call? Read how to hire a tree service or check is my tree dangerous?
Trees it affects
Usually seen on: Green ash, White ash, Other true ash trees.
See all species in our tree library, or pick a tougher tree with the tree picker.
For tree companies
How to explain emerald ash borer to a customer
Be honest about what you can and cannot tell from the ground. Explain the signs you see, say that confirmation may need an official or expert check, and give the owner clear options: treat, watch or remove. Do not push removal or a treatment plan with fear. Written quotes and plain timelines build trust and referrals.
Send this page to the customer after your visit so they can read the signs in plain words. See also selling plant health care and the job photo checklist.
Questions
How do I know if my ash tree has emerald ash borer?
Look for crown thinning, D-shaped exit holes, S-shaped tunnels under the bark, sprouts on the trunk and woodpecker damage. Some of these also have other causes, so ask your extension office or a certified arborist to confirm.
Can an infested ash tree be saved?
Sometimes. Trees that are still healthy or only lightly affected may respond to treatment from a qualified arborist. Trees that have lost much of their crown usually do not recover well. Ask a pro to judge your specific tree.
Do I have to remove every ash tree on my property?
Not necessarily. Some owners protect valuable trees with treatment and remove others. Rules can differ by state and city, so check with your local authorities.
Is a dead ash tree dangerous?
It can be. Dead ash wood can become brittle and limbs may fall without warning. Keep people and vehicles away and have a qualified pro assess any dead ash near a building or road.
Can I burn ash firewood from my own yard?
Burning wood where it was cut is much safer than moving it. Do not carry ash firewood to other places, and check your state rules on moving wood.
Who do I report a suspected case to?
Start with your state department of agriculture or county extension office. The USDA APHIS page for this pest explains how to report.
Can Lirevon diagnose emerald ash borer on my tree?
No. Lirevon is a remote marketing team for tree service companies and does not do tree work. This page is general information, not a diagnosis. A certified arborist or your county extension office can confirm what is wrong with your tree.
How do I find a good local pro for this?
Search Google Maps for certified arborists or tree services near you, read their reviews and ask for proof of insurance. Get two or three written quotes. Our guide on how to hire a tree service lists the questions to ask.
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