The adults are similar in size and appearance, but they bore directly through the bark and into the sapwood rather than in and under the bark. The larvae are raised in small galleries or cradles constructed at right angles to the entrance gallery. The fungus stains the surrounding wood, creating black holes or localized stains in the wood. Because moisture is very critical to the fungus culture, ambrosia beetle attacks are limited to recently dead or dying trees rather than drier wood, etc. The adult is the damaging stage with these beetles, as the larva do no tunneling.
Different species prefer different types of wood for attack.
This group varies greatly from the others above in that wood without bark is attacked. Various species attack both hardwoods and softwoods, but the latter is more commonly infested in Vermont buildings. The adults may also tunnel in the wood. Heavily infested wood is severely weakened and often fails in service, being largely reduced to powder by these beetles. If wood infested with powder post beetles is to be used for firewood, it should not be stored in structures.