August 18, 2021 ,

First discovered in Brooklyn, New York in 1996, the Asian Longhorned Beetle has caused destruction in six states and threatens to kill ornamental trees across the eastern half of the country. Homeowners in three key states should be vigilant for these destructive and invasive wood-boring pests as they can cause tree death to many beloved hardwoods in our region. 

the danger of the Asian Longhorned Beetle

What Are Asian Longhorned Beetles? 

While not native to the United States, the Asian Longhorned beetle (ALB) feeds on hardwoods by boring into the bark and eventually destroying the tree they inhabit. The ALB is considered an invasive and destructive species and has spread from New York initially to five other states where quarantines were enacted to reduce the spread. Those states include: Illinois, New Jersey, Massachusetts, Ohio, and South Carolina. 

The trees that are most at risk are Ash, Birch, Elm, Poplar, Sycamore, and Willow trees. These trees are currently at highest risk in Massachusetts, New York, Ohio, and South Carolina. 

Identification of these pests depends upon the stage they are in on their life cycle. The adult ALB are very unique looking in that they have black shiny bodies (about an inch to an inch and a half long) with distinctive white band markings and very long antenna. 

It’s during the larvae stage that the ALB does the most damage however. The larvae bore under the bark of the tree and feed on the tree much like the Emerald Ash Borer. The loss of nutrients can be deadly to the tree and cause irreversible damage. After boring to the core of the tree and pupating under the bark, the adult ALb then tunnels its way out causing a pencil-sized hole in the tree. 

As you can imagine both the larva stage and adult tunneling (boring) can put major stress on the trees and cause a depletion of much needed nutrients. 

Signs of ALB infestation

Signs & Symptoms Your Trees Are Infested with ALB

According to the United States Department of Agriculture, signs of ALB infestation “start to show about 3 to 4 years after infestation, with tree death occurring in 10 to 15 years depending on the tree’s overall health and site conditions.” 

Here are some signs that homeowners in these states mentioned above should take special care to be vigilant for as they inspect their trees regularly. 


  • Sightings of adult ALBs, larvae, pupa, or eggs on your hardwood trees.
  • Chewed round depressions in the bark. 
  • Frass or sawdust like droppings at the base of the tree. 
  • Pencil-sized exit holes caused by adults exiting the tree. 
  • Yellowed or drooping leaves. 

What You Can Do To Stop the Spread of ALB

In order to stop the spread of these invasive pests, homeowners should have the trees on their property inspected annually by a certified arborist, especially if you have noticed any of the signs listed above. Learn about the quarantines that currently exist in your area. 

In addition to learning about these destructive pests, homeowners should avoid moving firewood that could have the egg, pupa, larva, or even the adult ALB still hidden inside the bark.

If you should spot any of the signs of this species on your property, please report it immediately by calling 1-866-702-9938 or report online.