The larvae of these beetles, including the new house borer (Arhopalus productus) and the old house borer (Hylotrupes bajulus), cause damage to fir, pine, and other softwood structural timbers. New house borers generally do not cause structural damage; the holes they make in wood or covered wood surfaces are of cosmetic concern only. The adults lay their eggs in the bark of weak and dying forest trees and, in the case of old house borers, in seasoned lumber. The yellow grubs tunnel into wood that is later incorporated into a building before the adult beetles emerge. New house borers continue to emerge through holes in wood and wood coverings for up to a year after construction. They cannot reinfest the building. Old house borer beetles generally do not emerge from timbers until 3 to 5 years after the building has been constructed. It is the only species of roundheaded borers that reinfests wood, and may cause serious structural damage. Sometimes the grubs make rasping or clicking noises while they feed. If they are tunneling close to the surface, wood blistering or rippling may result.
New house borers are the problem if damage occurs within a year after construction. To repair new house borer damage, seal or fill emergence holes. Localized areas may be painted with ORTHO HomeDefense Ortho-Klor Insect & Termite Killer. Because damage is only cosmetic and will stop within a year, this expensive procedure is seldom justified. Old house borers are the problem if damage occurs at least 3 years after construction. Buildings infested with old house borers must be fumigated. Contact a professional pest control operator to fumigate the building. To prevent future infestations of old house borers when building new structures, purchase pressure-treated wood.