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How to identify it
- Adults are about 1 to 1 1/2 inches long, with a shiny black body like patent leather and scattered white spots on the back.[2][3][1]
- The antennae are banded black and white; in males they are longer than the body, while in females they may be only about body length.[2][1]
- The feet and legs often look bluish, one of the details that separates it from native look-alikes.[3][1]
- Exit holes are round, about 3/8 inch across, roughly dime-sized or smaller.[2][1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Whitespotted sawyer | A native longhorned beetle with a single distinct white spot near where the thorax joins the abdomen; it lacks white bands on the antennae and bluish feet.[4][3] |
| Cottonwood borer | Slightly larger, up to about 2 inches, mostly white with black spots, with solid black antennae and no bluish feet.[3] |
| Prionid beetles | Large brown longhorned beetles without white spots on the body or antennae.[3] |
Where it lives
First found in the United States in Brooklyn in 1996; current quarantine areas are in Worcester County, Massachusetts, central Long Island, New York, Clermont County, Ohio, and Charleston County, South Carolina.[2][1]
Biology and life cycle
It readily attacks 12 genera of hardwoods; maples are the favorite, and horsechestnut and buckeye, birch, willow and elm are also commonly hit. Conifers are not attacked.[2][3]
Females chew individual pits in the bark and lay one egg in each; larvae feed under the bark, then tunnel deep into the wood.[2][3]
Larvae spend one or two seasons in the tree before pupating, and in Massachusetts adults begin emerging around July 1 and stay active into fall.[2]
Adults spend little time outside the tree and feed on the bark of twigs before laying eggs.[3]
Damage and signs
- Signs include round exit holes, oval or round egg pits chewed in the bark that may ooze sap, and sawdust-like frass on the ground or in branch crotches.[1][2]
- Larval galleries weaken the wood, so branches can break off an otherwise healthy-looking tree; leaves may yellow early or show chewed veins.[1][3]
- Several years of infestation eventually kill the tree.[2]
Health risk
The beetle damages trees rather than people; the hazard is limbs breaking from trees weakened by larval tunnels.[3]
Control
Prevention
Don't move firewood out of quarantined areas, buy and burn firewood locally, and choose kiln-dried firewood when you can.[1][2]
Traps and physical control
Infested trees can't be treated or saved; eradication programs remove them and chip or burn the wood.[1][3]
Pesticides
Contact insecticides kill adults but aren't effective because adults spend so little time outside the tree, and nothing works once larvae are inside.[3]
When to call a professional
Report a suspected beetle or damage: photograph it, freeze any captured beetle, and call the USDA ALB hotline at 1-866-702-9938 or report online.[1][2]
Common questions
- I found a big black beetle with white spots. Is it an Asian longhorned beetle?
- Most are native whitespotted sawyers; check for black-and-white banded antennae and bluish feet, and if they match, photograph the beetle and report it.[4][3][1]
- Can a tree with Asian longhorned beetle be saved?
- No. Infested trees can't be treated; the only way to destroy the insect is to remove the tree and chip or burn the wood.[1][3]
Sources
- USDA Animal and Plant Health Inspection Service, “Asian Longhorned Beetle (last modified September 17, 2026).” www.aphis.usda.gov/plant-pests-diseases/alb (accessed 2026-10-06)
- UMass Extension, “Asian Longhorned Beetle (Landscape, Nursery and Urban Forestry fact sheet).” www.umass.edu/agriculture-food-environment/landscape/fact-sheets/asian-longhorned-beetle (accessed 2026-10-06)
- Clemson Cooperative Extension Home & Garden Information Center, “Asian Longhorned Beetle (HGIC 2021).” hgic.clemson.edu/factsheet/asian-longhorned-beetle/ (accessed 2026-10-06)
- University of Maine Cooperative Extension, “Whitespotted Sawyer Beetles (Home and Garden IPM, Frequent Specimens).” extension.umaine.edu/home-and-garden-ipm/frequent-specimens/whitespotted-sawyer-beetles/ (accessed 2026-10-06)
- iNaturalist, “Anoplophora glabripennis taxon page (order and family).” www.inaturalist.org/taxa/128525 (accessed 2026-10-06)