Longhorned Beetles




  • Longhorned beetles are typicall large (1/2 to 3 inches long) and man are brightly colored (approximately 1200 species in the Unites States).
  • They have thin antenna which may be linger than the body.
  • Eggs usually are laid unseasoned, rough-sawed timbers or logs.
  • The larvae, called round-headed borers, feed in the wood; they bore large, oval holes as they move through the wood.

The adults of the borers will emerge from the wood after it has been incorporated into a structure. This can occur in flooring, siding, fencing, and other wood products. They will not re0infest the wood because of its dryness, but they are of great concern to property owners who find them or evidence of their activity. A very colorful species that has been observed emerging from flooring recently is the Ivory-marked longhorn beetles. Although they do no re-infest the wood, they can continue to emerge for years.

The most common structural pest isn this beetle family is the old-house borer. The adult is about 3/4 inches long, grayish-brown to black, and has two white patches on the wing covers. The old-house borer usually damages only soft woods such as pine. It can be recognized by ripples on the surface of the galleries. Infested wood may be drilled to allow the injection of pesticide to penetrate into these areas; structural fumigation under tarpaulin sometimes may be necessary for extensive infestations.