Identification and Life Cycle
Powderpost beetles are wood-boring insects that breed in dead wood, untreated dried wood, and cured lumber. Its name comes from the larvae feeding and reducing wood to a very fine dust or powder.
They are very small, 1/8 to 3/4 – inches long, have a flattened shape, antennae, and are reddish to dark brown in color. The two more common species are the Lyctidae and Anobiidae. Mature larvae are “C” shaped and slightly hairy. They have three pairs of small, spinelike legs behind its head, and are a whittish-cream color with a tan head.
They have 3 life cycle stages; egg, larva and pupa. The adult female beetle lays eggs in the pores of untreated wood. The eggs hatch into tiny larvae that bore into the wood as they feed while leaving behind a white powder called “frass”. This matter is composed of very fine particles of wood and fecal pellets, and has a gritty feel to it. Their life cycle may take up to 2 to 3 years to complete.
Habits and Damage
Powderpost beetles breed and feed outdoors in untreated hardwoods such as in the limbs of trees, but can also bore into lumber used for rafter, joist, finished wood, and furniture products while it’s being stored and cured. They can then emerge from inside your home, sometimes years later. Damage is typically not evident until the adult emerges from the wood and leaves behind pin-holed sized openings (1/16 to 1/8 – inch in diameter) or piles of a powdery substance (frass). If environmental conditions are suitable, the female will lay her eggs and re-infest the same wood for generations.
The Lyctid beetle infests mostly large pored hardwoods such as oak, ash, walnut, etc. Infestations can be found in wood paneling, molding, hardwood floors, window and door frames, and furniture
The Anobiidae beetle prefers both damp hardwoods and softwoods. Infestations usually start in moist, poorly ventilated areas such as basements, garages, and crawl spaces, which can spread to areas such as studs, subflooring, joists, walls, and furniture.
The proper identification by an expert is important since there are some look-alike beetles, such as the bark beetle that infest firewood.
Prevention and Management
The best strategy for powderpost beetle control is prevention. An Integrated Pest Management (IPM) program can properly identify and help you maintain a pest-free environment for your level of infestation.
It is important to recognize and take corrective measures around a home or building based on the severity of a powderpost beetle infestation. A thorough inspection can identify the insect and determine if damage left behind is from an active or in-active infestation.
An active infestation will have a fine wood powder sifting from the exit holes. If it is an un-active infestation, the wood powder piles will more likely be covered over with dust or debris. To help determine a new infestation, mark or seal exit holes, sweep or vacuum the powder and re-check at a later day. Powerpost beetles commonly do use the same wood to nest and new beetles may emerge from new holes during the months of April to July.
The following steps can be taken to help prevent or reduce a problem with powderpost beetles.
- Replace damaged wood in localized areas if showing a few holes. If additional holes appear, take action.
- Provide suitable drainage for basements, cellars, and crawl spaces under the building to reduce moisture.
- Dry out damp areas by using a dehumidifier.
- Do not store valuable wood items in outbuildings such as sheds and barns where beetles can easily infest.
- Since the beetle already inside the wood causes most infestations, check lumber or unfinished wood for exit holes before using.
- Paint, varnish, and seal exposed wood surfaces making it unsuitable for the female to lay eggs.