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Tree Care: An Introductory Guide

Dealing With Asian Longhorn Beetle Infestations In Residential Trees

11 September 2023

Same Peterson

Tall, stately trees can be a beautiful addition to any home, but they can become host to damaging insect pests. Many species of insect can severely damage your trees, but the Asian longhorn beetle is particularly notorious. If you spot signs of Asian longhorn beetle infestation on your home's trees, acting quickly is absolutely vital.

How Do Asian Longhorn Beetles Damage Trees?

The Asian longhorn beetle is an invasive species from Asia. They are large, black beetles, with highly distinctive white spots on their carapaces. Unlike other insect pests, which generally target specific tree species, Asian longhorns can damage and destroy a wide variety of common American tree species, including maples, willows, and sycamores.

Asian longhorn beetles damage trees by chewing pits into their bark. Female beetles lay their eggs inside these pits. When the eggs hatch, the larvae burrow deep into the tree's trunk and branches. Just a few beetles can lay hundreds of eggs in a short time period, so a stricken tree can quickly become riddled with holes and tunnels.

The damage caused by Asian longhorn larvae can cause trees to shed large branches unpredictably and leaves the tree critically vulnerable to fungal and bacterial infections. Larvae burrowing through the tree's trunk can also cause structural damage, and badly damaged trees may topple in high winds.

How Can You Spot Asian Longhorn Beetle Infestations?

Check the bark of your trees for egg-laying pits created by the beetles. These pits have a distinctive oval shape and may be very deep if the eggs within have already hatched. They may leak sap if hatched larvae have started attacking the tree's living wood.

You should also check for a sawdust-like substance around the base of your trees. This will be easiest to spot on dry, windless days. This substance is called frass and is left behind by larvae as they voraciously consume the tree's bark and wood.

If the tree has been infested for some time, you may also spot circular exit holes. These are created when larvae pupate into adult beetles. The adult beetles chew their way out of the tree to escape, causing even more damage.

Your Tree Is Infested — What Should You Do?

If you suspect a tree on your property is infested with Asian longhorn beetles, you must inform the United States Department of Agriculture (USDA) as soon as possible. This invasive beetle is spreading rapidly across wide swathes of the country, and you may be required to follow quarantine measures (such as not transporting firewood out of the area).

Unfortunately, because Asian longhorn beetle larvae are hidden deep within the trees they attack, insecticides are usually ineffective. The only option is to have infested trees removed and destroyed by a professional residential tree care service. These services will safely fell the doomed trees, uproot their stumps, and chip and destroy the entire tree on your property. This prevents the beetles from spreading to other areas.

Having to destroy your prized trees can be pretty depressing, but if there are unaffected trees on your property, it may be possible to save them. Consult with your chosen tree care service, and have them inspect your other trees for signs of damage. They may be able to treat undamaged trees with powerful, long-lasting surface insecticides, which will kill beetles attempting to lay their eggs. 

Contact a local company to learn more about residential tree care.

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