Old House Borer Beetles

Hylotrupes bajulus



The Old House Borer Beetle actually appears in newer homes, seeking our seasoned softwood with a moisture content of between 10% and 20%. In its larval stage, the Old House Borer Beetle feeds on this wood, leaving holes that measure about 1/4 in wide. Larvae will feed on the wood for from 2 to ten years before emerging as an adult.

Old House Borer Beetles are dark brown to black in color and measure about 5/8 to 1 inch in length, with wing coverings that are typically black with white markings. The adults will mate after leaving the wood they fed on during their larval stage, and will live only about 10 to 15 more days.

The average life cycle for the Old House Borer ranges from 3 to 5 years, but can be as long as 12 years, based on the environment and nutrition conditions.


The rasping or clicking sounds of large larvae sometimes can be heard from infested timbers, especially during Spring and Summer months, when wood moisture is relatively high. (Factoid Source: Barbara L. Thorne, Ph.D and Nancy L. Breisch, Ph.D, Department of Entomology, University of Maryland)