The name “powderpost” is used for three different groups of beetles. The three groups are Lyctid beetles, Bostrichid beetles, and Anobiid beetles. Some people call them wood-boring beetles.
The larvae of powderpost beetles eat wood and cause damage. The beetles get their common name from the powder that the larvae produce when they eat wood. Scientists use the word frass for the powder that the larvae produce.
The Lyctid beetles normally attack only hardwood. These tiny beetles can infest molding, cabinets, decorative items, and flooring. They have a short life cycle – usually a year or less. The Lyctid beetles can often re-infest the same wood where they emerge.
The Bostrichid beetles can attack both softwoods and hardwoods. These beetles can develop in one year. However, if the wood becomes very dry, they can take more than five years to complete their life cycle. Adults range in size from 1/8″ to ¼” depending on the species. They do not normally re-infest, so damage is usually limited.
Anobiid beetles can attack both softwoods and hardwoods. There are more than 200 species of anobiid beetles in the United States. They attack lumber, structural timbers, and manufactured products. These beetles require high humidity, so they are more common in the southeastern United States and the coastal areas.
The adult powderpost beetles deposit their eggs on the wood. When the eggs hatch, the larvae burrow into the wood. They eat the wood and create tunnels. Some species make loud sounds when they are tunneling in the wood.
The larvae pack the tunnel with their droppings and wood particles. The appearance of this frass is one of the clues for identifying the beetle that is attacking the wood.
Depending on the species, the larvae can complete their life cycles in as little as a year. Some species can live in the wood for several years. When they are fully developed, the larvae change into adult beetles. The adult beetles dig their way out of the wood to find mates and lay eggs.
When the adult beetles come out of the wood, they make exit holes. The size and shape of the exit holes help to identify the type of beetle that is present. When the adult emerges, some frass usually falls out of the hole. This falling frass is often the homeowner's first clue that beetles have been active.
Controlling powderpost beetles can involve a variety of procedures. If the infestation is confined to a small area, the simplest solution is to replace the infested wood with new wood.
There are a variety of chemical control methods. Liquid insecticides can be sprayed on the surface of bare wood or injected into the larval galleries. Valuable items like antique furniture can often be fumigated in special vaults. Fumigation of the entire structure is normally only done when the infestation is severe.
Experts recommend keeping firewood stacked outside until it is time to burn it. Logs can be infested with beetle larvae. The warm climate in the home can make the beetles finish their life cycle and emerge. Beetles that were brought indoors in firewood have infested many homes.
Homeowners who suspect they have powderpost beetles should contact a pest control professional who is licensed in this category. The pest control professional can identify the type of powderpost beetle, confirm whether the infestation is active, and discuss the most effective and economical treatment options.