Roundheaded Borer

Round-Headed Borer  Family: Cerambycidae

Common names; longhorn beetles, timber beetles, round-headed wood borers, cerambycid beetles.

Longhorned beetles crawl about the house creating a nuisance but they cannot bite, sting, attack furniture or damage the house structure.

Habitat

Roundheaded borers attack recently cut trees or timbers from which bark has not been removed. Improperly edged lumber, with pieces of bark still attached, may be targeted. 

Food

Stressed, recently dead, or dying trees are often attacked. In lumber piles, the larvae tunnel from board to board causing heavy damage. 

Biology

Adult cerambycid beetles vary in size and color and are identified most readily by their extremely long antennae, which often are longer than the body. Larvae are white, long, slender, and usually legless. Most cerambycids infesting structural timbers in the PNW complete their life cycle in 2 to 3 years and do not re-infest.

Threat

The cost of damage in lumber yards can be extensive. Roundheaded borers are commonly found in firewood, and the longhorned beetles may emerge from wood brought into the house. These beetles may also wander into houses by mistake as “accidental invaders.” Longhorned beetles crawl about the house creating a nuisance but they cannot bite, sting, attack furniture or damage the house structure.

Detection

Injury caused by roundheaded borers is characterized by borings that have mixed fibrous and powdery material. The tunnels tend to lie within the annual rings, but this is not always the case. Adult beetles make circular exit holes and these are often the first evidence of an infestation. 

Prevention

The best way to prevent the nuisance of insects emerging from firewood is to leave the firewood outside until it is to be burned.