NYC Resources311Office of the Mayor

Asian Longhorned Beetle Alert: What to Look For

Oval to round pits in the bark

The adult ALB is 3/4 to 1 1/4 inches long, with a shiny jet black body mottled with white spots on the back. Its black-and-white striped antennae are 1 1/2 to 2 1/2 times as long as the beetle's body. The adult beetles are usually present from May through October.

image of asian long horned beetle

Female beetles chew oval to round pits in the bark of trunks and large branches and deposit a single egg in each niche. A typical female will lay 25 to 40 eggs in her lifetime (about 40 days).

image of asian long horned beetle damage

Accumulation of coarse sawdust

The eggs hatch in 10-15 days. The larvae tunnel through the bark and into the heartwood of the tree to pupate. This action results in an accumulation of coarse sawdust around the base of infested trees, where branches meet the main stem, and where branches meet other branches.

image of asian long horned beetle damage

Round Holes

Adult beetles emerge from the pupation sites by boring through the wood, leaving an approximately 3/8-inch diameter exit hole on the trunk and branches. The adults usually remain on the same tree and feed on twig bark.

image of asian long horned beetle damage

Oozing sap

Oozing sap and small piles of sawdust may indicate an ALB infestation.

image of asian long horned beetle damage

Was this information helpful?