The Asian Longhorned Beetle

What is the Asian Longhorned Beetle?

The Asian Longhorned Beetle (Anoplophora glabripennis, often shortened to ALB) is a large wood-boring insect native to China and the Korean Peninsula that has become one of the most serious invasive threats to hardwood trees in North America. It belongs to the long-horned beetle family, Cerambycidae, named for the exceptionally long antennae the adults carry. It matters because, unlike many pests that only weaken a tree, ALB reliably kills healthy hardwoods: its larvae tunnel through the living wood until the tree can no longer move water and nutrients, and there is no way to save an infested tree once the larvae are inside.

First found in the United States in Brooklyn, New York in 1996, the beetle arrived — and continues to move — inside solid-wood packing material and firewood. Because a single female can start a new infestation and the larvae stay hidden inside the wood for a year or more, ALB is treated as a quarantine pest: federal and state programs work to detect and eradicate it wherever it appears before it can spread into America's maple-rich forests and shade trees.

What does an Asian Longhorned Beetle look like?

An adult Asian Longhorned Beetle is a large, glossy jet-black beetle with irregular white spots and long antennae banded in black and white. Adults are roughly 1 to 1.5 inches (2.5–3.8 cm) long — big enough to notice on a tree trunk or a window screen. The antennae are longer than the body (up to about twice the body length in males), and the legs and feet often have a distinct bluish-white cast. The card below summarizes the field marks; for the full identification walk-through, including the native beetles it is confused with, see the identification guide.

What trees does the Asian Longhorned Beetle attack?

The Asian Longhorned Beetle attacks a wide range of hardwood trees, but its clear preference is maple (genus Acer) — including sugar, red, silver, Norway, and boxelder maples. In North America it is capable of infesting trees across roughly a dozen genera. Alongside maple, confirmed host groups include:

• Birch (Betula)
• Willow (Salix)
• Elm (Ulmus)
• Poplar and cottonwood (Populus)
• Horsechestnut and buckeye (Aesculus)
• Ash (Fraxinus) and mountain ash (Sorbus)
• London planetree and sycamore (Platanus)
• Mimosa (Albizia), katsura (Cercidiphyllum), and golden raintree (Koelreuteria)

Importantly, the beetle does not attack conifers — pines, spruces, and firs are not hosts. That single fact rules out several native look-alike beetles that are found only on evergreens. For the full host list and how infestation progresses in each, see damage and host trees.

What damage does the Asian Longhorned Beetle cause?

The Asian Longhorned Beetle kills trees by tunneling: female beetles chew shallow pits in the bark and lay eggs, and the larvae that hatch bore deep into the sapwood and heartwood, carving large galleries that sever the tree's internal plumbing. Over one to several years this internal damage girdles branches and trunks, and infested trees decline and die. Because the larvae work out of sight, the outward signs are what give an infestation away:

• Round exit holes about ⅜ inch (roughly 3⁄8 in, dime- or pencil-sized) where adults chewed their way out of the wood.
• Oval egg-laying pits — shallow chewed niches in the bark, about ½ to ¾ inch across.
• Frass — coarse, sawdust-like material that collects in branch crotches and at the base of the tree.
• Oozing sap and dark, wet streaking on the bark near larval tunnels.
• Canopy dieback — dead limbs, yellowing or wilting leaves out of season, and thinning crowns.

Any one of these signs on a maple or other host tree is worth a closer look. Round, dime-sized holes and coarse frass together are a strong warning.

Where is the Asian Longhorned Beetle found in the United States?

As of 2026, active Asian Longhorned Beetle quarantines exist in four US states — Massachusetts, New York, Ohio, and South Carolina — covering a few hundred square miles in total. Each zone is the focus of an ongoing federal–state eradication program:

• Massachusetts — the Worcester County area, first detected in 2008 and still the largest US infestation. Regulators have been steadily shrinking it, removing the Town of Holden from the quarantine in 2025.
• New York — a remaining zone on central Long Island (parts of Nassau and Suffolk counties). Earlier New York City infestations have already been eradicated.
• Ohio — Clermont County, southeast of Cincinnati, first detected in 2011, with portions progressively deregulated as areas are cleared.
• South Carolina — the Charleston/Dorchester county area around Hollywood, first detected in 2020 — the first confirmed infestation in the US Southeast.

Beyond these active zones, the beetle has turned up in other states and been eradicated. If you live near a quarantine — or think you have seen the beetle anywhere — the single most useful thing you can do is report it. Our report a sighting page lists the state programs and the national reporting channel.

Is the Asian Longhorned Beetle dangerous to humans or pets?

No — the Asian Longhorned Beetle is harmless to people and animals. Despite its large size and strong jaws, it does not bite or sting humans or pets, and it does not carry or transmit any disease. Its entire threat is to trees. The only indirect risk to people is structural: trees killed by ALB become brittle and can drop heavy limbs or fall, which is one reason infested trees are removed rather than left standing.

Can the Asian Longhorned Beetle be controlled or eradicated?

Yes — the Asian Longhorned Beetle can be eradicated, and it already has been in several US areas. Eradication works by finding every infested tree through intensive ground and climbing surveys, removing and chipping or burning those trees, and, where appropriate, treating nearby healthy host trees with an insecticide (imidacloprid, applied by trunk or soil injection) to kill beetles before they can bore into the wood. Movement of firewood, logs, and nursery stock out of quarantined areas is restricted to keep the beetle from hitchhiking to new locations.

This approach has succeeded repeatedly. The beetle has been declared eradicated from Chicago, Illinois (2008); parts of New Jersey; the Boston area of Massachusetts (2014); and several New York City boroughs — including Manhattan and Staten Island (2013) and Brooklyn and Queens (2019) — as well as areas of Ontario, Canada. Eradication is slow and expensive, but it is achievable, which is exactly why early reporting matters so much.

How is it different from native look-alikes?

Several harmless native beetles are mistaken for the Asian Longhorned Beetle, and telling them apart usually comes down to the antennae, the body sheen, and the host tree. The native whitespotted sawyer, for example, has a single white spot where its wing covers meet and lives on conifers — a tree group ALB never attacks. Because most reports of "ALB" turn out to be a native look-alike, it is worth checking the distinguishing marks before you worry. Our identification guide lays out each look-alike side by side with the one feature that gives it away.

About the "BeetleBusters" name

The name "BeetleBusters" comes from the public-awareness campaign that first taught Americans to recognize and report the Asian Longhorned Beetle. This site continues that educational mission as an independent resource — we are not affiliated with the USDA, APHIS, or any government agency, and we do not speak for them. What we do is translate official federal and university guidance into plain language a homeowner can use, and point you to the right official channel when it is time to report. When we send you somewhere to file a report, it is always the responsible agency's own reporting line.