Anobiid Powderpost Beetles

Order/Family: Coleoptera/Anobiidae

Scientific Name: Various

Description: Various anobiid beetles attack seasoned wood in the United States. These beetles range in size from 1/32- to 3/8-inch long; however, those that attack structures are 1/8- to 1/4-inch long. They have highly variable body forms but most are elongate and cylindrical. The first body segment (pronotum) is hood-like, hiding the head when viewed from above. The last three segments of the antenna are lengthened and expanded into a club. The mature larvae are as large as 1/2-inch, C-shaped, dirty white, and the area behind the head is expanded and swollen. The last spiracle on the abdomen is not enlarged.

The furniture beetle, Anobium punctatum, is 1/8- to 1/4-inch long, cylindrical, and red-brown to dark brown in color. It has a series of pits in rows that run lengthwise on the wing covers. The pits can be seen through the fine yellow hairs that cover the body. The last three segments of the antenna are longer than the first eight combined.

The adult deathwatch beetle, Xestobium rufovillosum, is 1/4- to 3/8-inch long and is gray-brown with patches of pale hairs on the back of the body. It does not have the rows of pits on the wing covers and their 11-segmented antenna end in three elongated segments that are as long as the previous five segments.

Biology: Furniture beetle adults emerge in the spring from cells just below the surface of the infested wood. Soon afterward, mating occurs, and egg laying begins. The female lays 20-60 eggs in old emergence holes or cracks and v in the wood. Eggs hatch in six to 10 days. The larvae feed for about one year before pupating for two to three weeks. The wood moisture content required for larval development is 13-30%. When development is complete, the adult bores directly to the surface of the wood, emerging through a round hole 1/16- to 1/8-inch in diameter. Development under ideal conditions can be completed in one year; however, two to three years is more common. The adults are active at night. Some species are attracted to light.

Habits: These beetles commonly infest seasoned sapwood of hardwoods and softwoods; they are rarely found in heartwood. They attack structural timbers, lumber, cabinets, and furniture. These beetles re-infest, and the females commonly lay eggs in the wood from which they emerged. The larvae typically follow the grain of the wood when feeding ad fill their tunnels with wood frass. The frass is a fine powder with long pellets loosely packed into the galleries.

Control: Determine if the infestation is active before initiating treatment. Wood in structures and furniture infested by these beetles may go unnoticed until the round adult emergence holes appear in the surface. The characteristic pellets found in the frass and the consistency of the frass are useful in determining what species is infesting the wood. Infested wood can be removed and replaced with treated wood. Reducing the wood moisture content to approximately 12% slows the development of the larvae.

Galleries of existing infestations can be injected with aerosol, liquid or dust formulations. The surface of unpainted or otherwise unprotected wood can be treated and the galleries injected.  This kills exposed larvae and prevents re-infestation when the eggs hatch and immature larvae begin to penetrate the wood. 

Copyright © 2001 [Alan Luke]. All rights reserved.
Revised: 06/25/10. Home