If you spotted a large black beetle with white spots and long striped antennae near your Orange home, it's worth taking a closer look. The Asian longhorned beetle is an invasive insect that kills hardwood trees from the inside, and it has turned up in New Jersey before. Most of the time, the beetle people find is a harmless native lookalike. Below, we'll cover how to identify an Asian longhorned beetle, the damage it leaves behind, how to tell it apart from similar beetles and what to do if you think you've found one. If you're not sure what's around your property, our pest inspection services can help you sort it out.
What The Asian Longhorned Beetle Is
The Asian longhorned beetle is a wood-boring beetle native to Asia. It reached North America inside wood packing material, such as pallets and crates used in shipping. Adults are large and easy to notice once you know what to look for:
- Body. Shiny black, roughly an inch to an inch and a half long, with irregular white spots on the wing covers.
- Antennae. Very long, often longer than the body, with distinct black and white bands.
- Feet. Often have a bluish tint.
Adults are most active from summer into early fall. That's when you're most likely to see one on a tree trunk, a car, a deck or a window screen. Larvae spend most of their lives hidden inside the wood, so the damage on the tree is usually what gives an infestation away long before anyone sees an adult.
Why It Matters For Your Trees
Unlike bark beetles, which mostly go after stressed trees, the Asian longhorned beetle attacks healthy hardwoods. Maples are a favorite, and it also feeds on trees like birch, elm, willow, horse chestnut and poplar. Females chew small pits in the bark and lay eggs inside. The larvae tunnel deep into the wood, cutting off the tree's ability to move water and nutrients. Over several years, an infested tree weakens and dies, and dead limbs can drop without warning.
New Jersey has dealt with this beetle before and eliminated its known infestations through a long state and federal effort. That effort involved surveying trees and removing infested ones. Early reports from homeowners are a big part of how new infestations get caught.
Signs Of Asian Longhorned Beetle Damage
- Round exit holes. Perfectly round holes in the trunk or branches, about the size of a pencil or larger.
- Egg sites. Small oval or round pits chewed into the bark, sometimes weeping sap.
- Coarse sawdust. Frass collecting at the base of the tree or where branches meet the trunk.
- Dying branches. Yellowing leaves out of season or dead limbs in an otherwise healthy-looking tree.
Common Lookalikes
Several native beetles have long antennae and dark bodies, and they're far more common. The one people most often confuse with the Asian longhorned beetle is the white-spotted sawyer.
| Asian Longhorned Beetle | White-Spotted Sawyer | |
|---|---|---|
| Color | Glossy black with bold white spots | Dull black or bronze, often mottled |
| Key mark | No white spot where the wing covers meet | One white spot where the wing covers meet, just behind the head |
| Trees it uses | Hardwoods such as maples | Pines and other conifers, usually dead or dying |
| Status | Invasive, should be reported | Native, not a reportable pest |
If the holes you're seeing are D-shaped and the tree is an ash, read our guide to emerald ash borer signs instead.
Is It A Threat To Your House?
No. The Asian longhorned beetle needs living trees. It doesn't infest the dry framing, floors or furniture in your home. Firewood is the bigger concern, because moving infested wood is one of the main ways the beetle spreads. If you're finding holes and powder in wood inside your house, a different insect is at work, and a professional inspection can tell you which one.
What To Do If You Find One
- Take clear photos. Get the beetle, the antennae and any holes or damage on the tree.
- Capture it if you can. Put the beetle in a sealed jar or container so it can be identified.
- Note the location. Write down the address and which tree you found it on.
- Report it. Contact the New Jersey Department of Agriculture or the USDA's Asian longhorned beetle program.
- Don't move firewood. Burn firewood where you buy it, and don't carry wood from one area to another.
When To Call A Professional
Suspected Asian longhorned beetle infestations are handled by state and federal officials, and tree removal or treatment is a job for a certified arborist. EcoFusion doesn't treat or inject trees. Where we help is figuring out whether the insects you're seeing are a tree problem or a house problem. Our NJ DEP-licensed technicians can inspect your yard, firewood and the wood inside your home and recommend a plan for anything that's trying to get inside.
A big black beetle with white spots is worth a photo and a report, even if it turns out to be a native lookalike. Keeping an eye on the maples and other hardwoods around your Orange home is one of the simplest ways to protect them.