| Structure-infesting anobiid beetles were surveyed in Washington homes and outbuildings during 1987-91. Hemicoelus gibbicollis (LeConte) is the predominant species infesting building timbers along coastal areas of Washington, Oregon, California, and British Columbia. Other anobiid species are present but are of minor importance. Adult beetles are difficult to find due to their small size, cryptic coloration, and sedentary behavior. Adults are active primarily during June, July, and August. Pheromones play a key role in mate location. Females produce in excess of 100 eggs and emergence of first instars ranges between 85 and 89%. Larvae feed for 3 to 6 years within wooden timbers in damp crawl spaces, basements, and outbuildings. Infestations may persist for 20 or more years before being detected. Wood moisture between 13 and 19% contributes to successful colonization of structural timbers. Symbiotic yeasts present in larval mycetomes aid in nutritional procurement. No correlation was found between live larvae present in wood and number of adult exit holes.;Douglas-fir, Pseudotsuga menziesii (Mirbel), is the predominant building timber infested, but softwood and hardwood species of any age can be attacked. Wooden building supports are often reduced to powdery frass with little or no structural strength. Lowering of wood moisture to 12% or less will reduce the numbers of larvae found within timbers. Proper placement of vents to increase air circulation and a plastic vapor barrier to lower substructure moisture will help eliminate larval populations from wood. A borate insecticide, disodium octaborate tetrahydrate, reduced the numbers of larvae feeding within infested wooden timbers by more than 95%. Borates did not deter female beetles from ovipositing on wood, but effectively prevented larvae from emerging and penetrating into timbers. Borates can be easily adapted into an integrated control program for structure-infesting anobiids. |
