Tree problems · Insect
Asian longhorned beetle: signs and what to do
Asian longhorned beetle is an insect pest, often seen on maples, boxelder, elms. Look for: perfectly round exit holes about the size of a dime in the trunk or branches.
General information, not a diagnosis. A certified arborist or your county extension office can confirm.
- Insect
- Maples (including red, silver, sugar, Norway)
- Boxelder
- Elms
- Willows
- Birches
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 are active in summer and early fall. Larvae tunnel inside the wood for much of the year, so signs of damage can appear before anyone sees a beetle.
How it spreads
The beetle does not fly far on its own. Most spread comes from people moving infested firewood, logs, branches or nursery stock.
Where it is found
Asian longhorned beetle has been found only in a few limited areas of the United States, and these are managed under official quarantine. Check your state official map; ranges change.
Official sources
What to do
- 1
If you think you see this beetle or its damage, do not move any wood from the tree.
- 2
Take clear photos of the beetle, the exit holes and the tree. If you can safely catch a beetle, keep it in a sealed container and in a freezer as the agency advises.
- 3
Report it right away to your state department of agriculture or through the USDA APHIS page.
- 4
Do not cut down or dispose of the tree before officials have looked, unless safety requires it. Ask the agency first.
- 5
Never move firewood, branches or logs from a suspect tree.
- 6
In a quarantine area, follow the official rules for moving any tree material.
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 burn it. Never move wood out of a quarantine area. Check your own trees in summer for round exit holes and egg-laying scars. Learn the signs so early finds can be reported fast. Official programs depend on public reports.
When to call a pro
Call your state agriculture department first if you suspect this pest. A certified arborist can help look at your trees and handle safe removal, but official programs decide how infested trees are managed. Work in quarantine zones must follow the rules.
Not sure who to call? Read how to hire a tree service or check is my tree dangerous?
Trees it affects
Usually seen on: Maples (including red, silver, sugar, Norway), Boxelder, Elms, Willows, Birches.
- Red Maple
- Silver Maple
- Sugar Maple
- Norway Maple
- Boxelder
- American Elm
- Weeping Willow
- Black Willow
- River Birch
See all species in our tree library, or pick a tougher tree with the tree picker.
For tree companies
How to explain Asian longhorned beetle to a customer
If a customer shows you round exit holes or a black-and-white beetle, do not remove the tree on the spot. Say that officials need to see it first, help the owner report it, and explain the quarantine rules. Moving wood or chips from a suspect tree can spread the problem.
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
What does the beetle look like?
It is a large shiny black beetle with white spots and long antennae banded in black and white. Look at photos on the USDA APHIS page to compare.
What are the signs of damage?
Round exit holes about the size of a dime, shallow egg-laying scars, sawdust-like frass, dead branches and thinning leaves.
What should I do if I find one?
Take photos, do not move any wood, and report it quickly to your state department of agriculture or USDA APHIS.
Can infested trees be saved?
Official programs generally remove infested trees to stop spread. Ask the program about your situation.
Why can't I just cut the tree down?
Moving or chipping infested wood can spread the beetle. Officials need to confirm the find and tell you how to handle the wood.
Is it in my state?
Only a few limited areas have had it. Check your state official map; ranges change.
Can Lirevon diagnose Asian longhorned beetle 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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