Round-Headed Borer Family: Cerambycidae
Quick Look Pest Stats
Color: Dark brown, reddish, metallic hues present
Shape: Sub-cylindrical to flattened
Size: 5 – 50mm
Antennae: Yes, very long
Region: Found in North America
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.
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.
Stressed, recently dead, or dying trees are often attacked. In lumber piles, the larvae tunnel from board to board causing heavy damage.
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.
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.
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.
The best way to prevent the nuisance of insects emerging from firewood is to leave the firewood outside until it is to be burned.