We will discuss four types of Powderpost beetles in four families: Lyctidae, Bostrichidae, Anobiidae, and Cerambycidae. Adults do little damage, it is the larvae that does the major part of the damage. They go through a complete metamorphosis: adults, eggs, larvae and pupae.

True Powderpost Beetles (Lyctidae):

The adults are very small, less than 1/4" in size. They are flattened and reddish-brown to black in color. Larvae are white, cream colored, c shaped with dark brown heads. Larvae create tunnels in the wood and become pupae. As adults they bore out through the wood, pushing a fine powdery dust out. The shape of their holes are round ,about 1/32-1/16 pinholes.

They attack hardwoods depositing their eggs. They can attack bamboo (technically a grass), but because of the large pores they will attack. Their diet is starch, sugar and protein in the sapwood of hardwoods Wood that is less than 6% moisture content is seldom attacked .The life cycle averages one year to complete .This wood-boring beetle is the most widespread in the United States. Many times infestations are built into structures from infested lumber .They can reinfest.
Lycid damage is characterized by:

False Powderpost Beetle (Bostrichidae)

They are larger than other families of powderpost beetles...so their exit holes are larger. These holes do not contain frass,but the galleries do. The frass is tightly packed, tends to stick together and is meal like( contains no pellets)

The adults are 1/8-to 1-inch long, cylindrical, and reddish brown to black. The adults bore into the wood in order to lay eggs, leaving a hole larger that 1/8 inch, usually in wood less than 10 years old.

The larvae are curved and wrinkled. Their diet is dependent on the starch in the wood, they are more common in softwood ,but can attack hardwoods. They require 6-30% moisture content in the wood, and complete the average life cycle in one year. Most of the hardwoods attacked are not those commonly found used for interior floors, woodwork or trim. Most of this species does not reinfest wood after it is seasoned, so the damage is limited to that inflicted by one generation. However the speed of the damage can be considerable. Most of the time they do not reinfest wood after it has been seasoned. They are often found in oak, firewood and furniture.
 

Anobiid Powderpost Beetle (Anobiidae)- Furniture and Deathwatch Beetles

The furniture beetle is found mostly in the eastern half of the United States and it infests structural timbers as well. The Death-watch beetle is found throughout the United States. It attacks building timbers in poorly ventilated areas where moisture tends to collect. The name" Death watch" comes from the ticking sound that the adult makes inside infested wood that is audible during a still night. It is a mating call.

The insect is a common pest in the southeastern United States in crawl space timbers. Infestations can become so severe, that loss of structural strength to sills , joists, and sub flooring occurs.

The Adults are 1/8-1/4 inch long. They are red to dark brown in color and their shaped is usually oval. The adults lay their eggs in the cracks and crevices of seasoned wood. As soon as they hatch, larvae burrow into the wood where they live and tunnel for a year or more.

The larvae form tunnels in both softwoods and hardwoods They require 13-30% moisture content.

The larvae are slightly curved and wrinkled, with tiny hairs on the body.

Their holes are round,1/16-1/8 inches. They can digest cellulose from the wood. They are inclined to the softwoods ,for this reason they are common in crawl spaces and basements ,infesting the pine used as framing lumber.

The powder outside the holes (frass) is fine to coarse, many times with small pellets. The life cycle averages 1-3 years.

They commonly reinfest crawl space areas that are poorly ventilated and humidity is absorbed in the wood.