How to Get Rid of Emerald Ash Borers
A slim, bullet-shaped, metallic green beetle whose larvae tunnel beneath ash tree bark. It has killed hundreds of millions of ash trees across North America. If you are seeing them on trees and shrubs, the steps below will help you clear them out and keep them from coming back.
Quick answer
- Check ash trees for canopy thinning, bark splits and D-shaped holes
- Have a certified arborist evaluate systemic treatment for valuable ash trees
- Don't move firewood; buy or gather it where you will burn it
Emerald ash borers are harmless to people but lethal to untreated ash trees.
Confirm you have emerald ash borers
Correct identification matters, because the right fix for emerald ash borers differs from the fix for their lookalikes. Adults measure 8–14 mm (up to about 0.55 in) and are usually green and metallic. Look for these features:
- Bright metallic emerald green body
- Coppery-red upper abdomen visible when the wings open
- D-shaped exit holes about 1/8 inch wide in ash bark
They are most often confused with Japanese beetle. See the full emerald ash borer profile for side-by-side details.
Why you have emerald ash borers
Emerald Ash Borers spread on nursery stock, firewood, vehicles and outdoor furniture. Stressed or weakened trees are easier targets. Invasive species often lack natural enemies in North America. They are most active in summer, so expect to see more of them then.
When you'll see emerald ash borers
Emerald Ash Borers are most active in summer. Summer heat speeds up development, so populations can grow quickly.
Typical places to check: trees or shrubs.
Step-by-step: getting rid of emerald ash borers
Step 1: Check ash trees for canopy thinning
Check ash trees for canopy thinning, bark splits and D-shaped holes. Combine this with the other steps rather than relying on it alone.
Step 2: Have a certified arborist evaluate systemic treatment for valuable ash trees
Have a certified arborist evaluate systemic treatment for valuable ash trees. This is the step most people skip, and it is the one that makes the biggest difference.
Step 3: Don't move firewood; buy or gather it where you will burn it
Don't move firewood; buy or gather it where you will burn it. Keep notes on where you still see activity so you can focus your effort.
Natural and low-toxicity options
These methods work well alongside the steps above and keep chemical use to a minimum:
- Scrape off egg masses and destroy them.
- Band or trap trunks where your extension office recommends it.
- Prune and dispose of heavily infested branches.
- Water trees during drought to keep them vigorous.
If you do use a pesticide, choose one labeled for this pest and the place you're treating, and follow the label exactly. The label is the law.
When to call a professional
Hire a certified arborist to assess large or valuable trees, since treatment options depend on tree size, health and local rules.
How to keep emerald ash borers from coming back
- Don't move firewood long distances.
- Check vehicles and outdoor gear before leaving infested areas.
- Plant a diversity of tree species.
- Report invasive species sightings to your state agriculture department.
Safety notes
Emerald ash borers are harmless to people but lethal to untreated ash trees.
Keep children and pets away from any traps, baits or treated areas.
About beetles
The emerald ash borer is one of the beetles. Beetles go through complete metamorphosis: egg, larva (grub), pupa and adult. The larval stage often does the most feeding and damage, and it can last from a few weeks to several years depending on the species. Adults protect their flight wings under hard wing covers called elytra, which is why most beetles look armored and meet in a neat line down the back.
Look closely at larvae as well as adults. Grubs in soil, fuzzy larvae in closets and small worms in flour are all beetle larvae, and finding them tells you where the problem is centered.
Frequently asked questions
What is the fastest way to get rid of emerald ash borers?
Check ash trees for canopy thinning, bark splits and D-shaped holes. Most people see a clear drop in activity within one to three weeks when they combine this with sealing entry points and removing whatever attracts them.
Are emerald ash borers dangerous?
Emerald ash borers are harmless to people but lethal to untreated ash trees.
When are emerald ash borers most active?
Emerald Ash Borers are most active in summer.
What do emerald ash borers look like?
Bright metallic emerald green body. Adults measure 8–14 mm (up to about 0.55 in).