The lyctid beetle attacks only hardwoods, while the anobiid beetle attacks both soft and hardwood timbers. Powder-post beetles are typically brought into the house via the wood that had been used in construction, as building materials often become infested while being stockpiled in the lumberyard. In addition, the insects may also be brought into the house in finished wood products such as oak flooring, paneling and furniture.
Powder-post beetles lay eggs in the open pores, cracks and crevices in the surface of unfinished wood. Once the eggs hatch, the larvae feed and tunnel their way through the wood, breaking it down to a powder.
Depending on the temperature and the moisture content of the wood, the larval stage may vary from a few months to a few years. Just before emerging, the newly formed adult beetles chew small round exit holes in the wood surface – about 1/32 to ⅛- inch.
During the process of emerging, finely powdered wood called frass is generally pushed out in front of the body – this is often the first sign of infestation. Shortly after emerging, the beetles mate and lay eggs. Occasionally, they deposit the eggs in the mouth of an exit hole, thus re-infesting the same piece of wood. Because of this, some wood members have shown signs of extensive damage as a result of infestation by several generations of beetles.
In some cases, the homeowners themselves are responsible for the powder-post beetle infestation in the house. Under natural conditions, the beetles breed in dead branches and limbs of trees. When gathering wood for the fireplace, there is a possibility of picking up infested pieces and storing them in the basement or under the stairs for later use. If such infested wood is left in storage through the following spring and summer, the emerging beetles or other wood destroying insects might attack unfinished lumber such as girders, studs, joists, still plates and subflooring.