Powderpost beetles breed in dead and dried hardwoods such as the dead branches and limbs of trees. Their presence is overlooked until they are discovered in stored lumber, rafters, joists, finished wood, and furniture products. As a rule, they enter lumber while it is being stored and cured, then later, emerge from the finished product. Old items of furniture and wood antiques are especially vulnerable to attack by the beetles.
The powder post beetles include small wood boring beetles of at least three families, the Lyctidae or true powder post beetles, the Anobiidae or deathwatch beetles, and the Bostrichidae or branch and twig borers (sometimes called false powder post beetles).
The larvae of these beetles feed on cellulose in wood, and they can cause extensive damage to wood in
structures and homes if conditions are suitable to them. Moisture plays a key role in attack from these insects.
Losses are often heaviest in warm humid climates, but some species occur throughout the United States. In their feeding they reduce the wood to a fine powder, not unlike talcum powder in consistency. Holes left by emerging beetles are about 1/8 inch in diameter and round. They are sometimes called "shot holes.” A tool such as an awl can be helpful in determining the extent of damage. If the awl pokes in easily and deeply, the wood may be severely damaged.
Eggs are deposited in cracks, crevices, pores or old emergence holes in wood, or in tunnels made by the
females. A tiny larva hatches from an egg and burrows into the wood. It continues feeding and growing to maturity, when it burrows toward the surface and pupates. The adult emerges from the pupa and continues the tunnel to the surface. Adults leave the wood, mate, and then the females return to lay eggs. Exit holes and sawdust from beetles burrowing out are often the first symptom noticed.
Depending on the type of powder post beetle and the species, the life cycle may range from 3 months to
2 or more years. Some species are specific as to the types of wood they infest, while others are general feeders. However, they usually are either hardwood feeders, or softwood (conifer) feeders.
INSECT DIAGNOSTIC LABORATORY
Cornell University, Dept. of Entomology, 2144 Comstock Hall, Ithaca NY 14853-2601