Asian longhorned beetle (Anoplophora glabripennis)

Common Names: Asian longhorned beetle, ALB, starry sky beetle, sky beetle, basicosta white-spotted longhorn beetle

Description:

The Asian longhorned beetle (Anoplophora glabripennis) is a large, shiny black beetle with white spots that bores into and kills hardwood trees, especially maples [1][2]. Native to China and Korea, it reached the United States in 1996 inside wooden packing material and has triggered tree-removal eradication programs in several states [1][2]. MISIN tracks it because a single infested tree can seed an outbreak that kills many trees, and early reports from the public are key to stopping it [1].

Identification:

Adult Asian longhorned beetles are big ? about 1 to 1? inches (2.5 to 3.8 cm) long ? with a glossy jet-black body marked by irregular white spots [1]. Their most striking feature is a pair of very long antennae, longer than the body and banded in black and white; the legs and feet often look bluish [1]. Adults are out and easiest to see from early summer into early fall, with the most activity from late June through August ? which is why August is national "Tree Check Month" for spotting them [1]. Look for the beetles on trunks and branches, or for the round exit holes and coarse sawdust they leave behind [1].

At-a-glance cues:

1. Large (1?1? inch) shiny black beetle with white spots on its back [1]
2. Very long antennae banded black and white, longer than the body [1]
3. Legs and feet with a bluish tint [1]
4. Round exit holes about ? inch wide ? a pencil fits inside ? in trunks and branches [1]

Hosts:

The Asian longhorned beetle attacks living hardwood (broadleaf) trees. Maples are its favorite, but it also bores into many others ? including birch, willow, elm, horse chestnut and buckeye, poplar, and ash [1][2]. It does not attack pines, spruces, or other conifers [1]. It can turn up anywhere these trees grow: backyards, city streets, parks, and woodlots [1]. The beetle is native to China and Korea and was first found in the United States in New York in 1996; since then it has appeared in several states and in parts of Canada and Europe, carried there in wooden packing material [1][2].

Life Cycle:

The Asian longhorned beetle spreads the farthest by hitching a ride in wood ? especially firewood, logs, branches, and wooden crates or pallets moved by people [1][2]. The larvae feed hidden under the bark, so infested wood can look fine while it carries the pest to a brand-new area [1]. On its own, the beetle usually flies only a short distance ? most adults stay within about 600 feet of where they emerged [2]. A female chews small pits in the bark and lays her eggs one at a time, roughly 30 to 90 eggs in her life [1]. The eggs hatch in a few weeks, and the larvae tunnel deep into the wood, where they take one to two years to grow before chewing their way out as adults the next summer [1]. There is usually one generation a year, and adults die after the first hard fall freeze [1]. The simplest way to avoid spreading it: never move firewood ? buy it where you will burn it [1].

Impact and Damage:

For a homeowner, the Asian longhorned beetle is a tree-killer: its tunneling weakens and eventually kills the hardwood trees in your yard, and heavily tunneled limbs can break and fall [1]. Because the only proven response is cutting down infested and nearby host trees, an outbreak can strip the shade trees from a whole neighborhood [1].

In natural and urban forests, the beetle threatens maples and many other hardwoods that wildlife and people depend on, and it puts maple syrup production at risk [1]. The potential economic damage is enormous ? one assessment estimated that, if it spread widely, the beetle could threaten more than a billion trees in the United States [2]. It also harms the forest products and nursery industries [1].

Similar species:

Cottonwood borer (Plectrodera scalator) is a native beetle of similar size with a black-and-white pattern, but it carries far more white ? a bold, blocky look ? and its antennae are solid black, without the white bands of the Asian longhorned beetle [3]. It bores into the roots of poplars and willows, so it leaves no large round holes in trunks or branches [3].

Whitespotted pine sawyer (Monochamus scutellatus) is the native beetle most often mistaken for it. Both are large and black with long antennae, but the pine sawyer has a single bright white spot where the wing covers meet behind the head, duller and less distinct spots elsewhere, and no bluish tint ? and it attacks only pines and other conifers [3].

Citrus longhorned beetle (Anoplophora chinensis) is a close relative that looks nearly identical and attacks similar hardwoods; it is told apart mainly by the rough, bumpy bases of its wing covers, and it too is a regulated pest [1].

Northeastern pine sawyer (Monochamus notatus) is another large native longhorn with very long antennae, but it is mottled gray and brown rather than glossy black with crisp white spots, and it feeds on conifers [3].

Monitoring and rapid response:

Signs to watch for:

1. Round exit holes about ? inch across (a pencil fits inside) in trunks and large branches [1]
2. Shallow pits chewed in the bark where eggs are laid, sometimes with sap weeping out [1]
3. Coarse sawdust (frass) piled where branches meet the trunk or on the ground below [1]
4. Dead or broken limbs ? and the large black-and-white beetles themselves in summer [1]

What you can do:

1. Check your hardwood trees once a year, especially in August during "Tree Check Month," for the holes, pits, and sawdust above [1].
2. If you find a suspect beetle, try to catch it in a jar (or take clear photos from several angles), note the exact location, and report it [1].
3. Never move firewood, branches, or logs out of your area ? buy and burn firewood locally so you don't carry hidden larvae to new trees [1].
4. Natural area crews and land managers can help by organizing tree surveys across a site and reporting suspect trees to the eradication program rather than removing them on their own [1].

When to call a professional:

1. Always ? if you suspect Asian longhorned beetle, report it to your state agriculture agency or USDA APHIS right away. This is a federally regulated pest, and trained crews handle tree inspection, removal, and treatment under an official eradication program [1].
2. Do not cut down or treat suspected trees yourself; removing or moving the wood can spread the beetle [1].
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Ohio State University Extension (Ohioline). Asian Longhorned Beetle, ENT-75. ohioline.osu.edu
2. IUCN/ISSG. Global Invasive Species Database: Anoplophora glabripennis. iucngisd.org
3. Michigan State University Extension. Confusion with Asian longhorned beetle look-alikes. canr.msu.edu

---