Tree problems · Insect
Ambrosia beetles: signs and what to do
Ambrosia beetles is an insect pest, often seen on flowering dogwood, eastern redbud, crape myrtle. Look for: thin, noodle-like tubes of sawdust and waste (frass) sticking out of the trunk.
General information, not a diagnosis. A certified arborist or your county extension office can confirm.
- Insect
- Flowering dogwood
- Eastern redbud
- Crape myrtle
- Young or stressed landscape trees
- Many other woody plants
Signs to look for
Tick what you see. More ticks make it more likely, but only an on-site look can confirm.
0 of 5 signs ticked. Ticks stay in this browser only.
Season
Several generations can occur in a year, and in warm areas the beetles may be active almost year-round. Adults overwinter inside their tunnels. Attacks on small landscape trees are often noticed in spring.
How it spreads
Adult beetles fly to trees on their own. They are drawn to the smell of ethanol that stressed, dying or dead wood gives off. They carry a fungus into the tunnels that they feed on.
Where it is found
Ambrosia beetles of many kinds live across the United States. Check your state official map and your county extension office for the species near you; ranges change.
Official sources
What to do
- 1
Look for frass tubes on the trunk. Take clear photos before you touch anything.
- 2
Check why the tree is stressed: drought, flooding, root damage, cold injury or soil compaction.
- 3
Ask your county extension office or a certified arborist to confirm the pest and judge how much damage is done.
- 4
Know that once a tree is heavily attacked, extension sources say there are no effective controls and sprays are usually not practical.
- 5
Plan to replace a badly attacked tree, ideally with a native species that suits the site.
- 6
Remove and dispose of infested wood as your extension office advises, so it does not attract more beetles.
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
Good care is the best defense. Water during dry spells, mulch the root zone, protect roots from digging and traffic, and avoid wounding trees. Plant the right tree in the right place so it is less likely to become stressed. Ask your extension office whether a specific species in your area also attacks healthy trees.
When to call a pro
Call a certified arborist if a young or valuable tree shows frass tubes, sudden wilting or dieback, or if you are not sure whether the tree is stable. Removal of a dying tree near a house, driveway or power line is work for a trained, insured crew.
Not sure who to call? Read how to hire a tree service or check is my tree dangerous?
Trees it affects
Usually seen on: Flowering dogwood, Eastern redbud, Crape myrtle, Young or stressed landscape trees, Many other woody plants.
- Flowering Dogwood
- Eastern Redbud
- Crape Myrtle
- Sweetgum
- Bradford Pear
- Red Maple
- Black walnut
- American Chestnut
See all species in our tree library, or pick a tougher tree with the tree picker.
For tree companies
How to explain ambrosia beetles to a customer
Be honest that treatment after a heavy attack rarely saves the tree. Look for the stress that drew the beetles in and say so in plain words. Give the owner clear options: watch, remove or replace. Do not sell sprays as a sure fix.
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 are ambrosia beetles?
They are very small beetles that bore into the wood of trees and carry a fungus that they feed on. The tunnels and fungus can hurt the tree.
How do I know my tree has them?
The best sign is thin noodle-like tubes of sawdust sticking out of the trunk. Small holes and sawdust at the base are other signs. Ask an expert to confirm.
Do they attack healthy trees?
Most are drawn to stressed, dying or dead wood. At least one species is known to attack healthy trees. Ask your county extension office which kinds are active near you.
Can I spray to save an attacked tree?
Extension sources say that once a tree is attacked, there are no effective controls and sprays are usually not practical. Ask a certified arborist about your tree.
Should I remove the tree?
If it is heavily attacked or declining, replacement is often the plan. A pro can tell you whether it is safe to keep and how to dispose of the wood.
How can I stop it from happening again?
Keep trees healthy. Water in dry weather, mulch, protect the roots and avoid wounds. Healthy trees are less likely to give off the smell that draws the beetles.
Can Lirevon diagnose ambrosia beetles 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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