Red Headed Ash Borer

Neoclytus acuminatus (Forst.)

Key Features

  • Flaking bark
  • Sawdust excrement
  • Round holes in trunk
Red headed ash borer gallery exposed by removing bark
Red headed ash borer adult
Loss of leaves on branch damaged by red headed ash borer


Infested trees have flaking bark and shed the sawdust-like excrement produced by the borer. White, worm-like larva of these insects eventually make tunnels in the heartwood after engraving characteristic patterns beneath the bark. Tunnels that weave back and forth across the bark, will make distinct right angle turns, unlike emerald ash borer which makes more rounded turns at acute angles. Also these insects will not kill ash trees as rapidly as emerald ash borers. Holes seen in the side of the tree where adults emerge are round. Adults commonly emerge from piles of firewood.


Adults emerge early in spring and, after mating, deposit eggs beneath the bark of dead, unseasoned wood. They, and other closely related beetles, can be seen attacking ash trees in areas where trees are being killed by emerald ash borer. The larvae first feed beneath the bark then tunnel into the sapwood, often reducing it to fine powder.

Red headed ash borer gallery with tail and right angle turn

Management Recommendations

Apply residual insecticide in late August to kill adults as they emerge and larvae as they chew into bark. Reduce tree stress by watering.

Effective Pesticides

Active Ingredients include: Bifenthrin, Imidacloprid, Permethrin

landscape report
Purdue Landscape Report
Plant & Pest Diagnostic Laboratory