How to Identify the Asian Longhorned Beetle

The Asian Longhorned Beetle is a large beetle (3/4 to 1-1/4 inches long) with extremely long antennae (1.5 to 2.5 times its body length). Adult beetles are black in color with mottled white spots on their backs. Adults also have distinctive white bands on each antennal segment. During the summer and late fall, females chew egg laying depressions into the bark of host trees where they lay a single egg.

Photo of an adult Asian Longhorned Beetle.
Photo of an oviposition scar.
Oviposition Scar
Photo of an emergence hole.
Emergence Hole

Asian Longhorned Beetle larvae live and feed under the bark of trees and emergence during mid to late summer and into the fall. Emergence holes are perfectly round (3/8 inch in diameter) and are visible on tree trunks and branches greater than 1-1/2 inches in diameter. Sometimes frass (sawdust) can be seen in emergence holes, where branches meet the trunk of the tree or at the base of a tree. Heavily infested trees can be riddled with emergence holes.

Photo of an emergence hole with frass.
Emergence Hole with Frass
Photo of a heavily infested tree.
Heavily Infested Tree

Click on any photo for larger version.

  1. Rutgers
  2. Executive Dean of Agriculture and Natural Resources
  3. School of Environmental and Biological Sciences