Lyctid Powderpost Beetles Order/Family: Coleoptera/Lyctidae Scientific Names: Lyctus planicollis (LeConte) - Southern Lyctus Lyctus cavicollis (LeConte) - Western Lyctus Beetle Lyctus brunneus (Stephens) - Brown Lyctus Beetle Trogoxylon parallelopipedum - Velvety Powderpost Beetle

Click picture to enlarge  Description: There are several other species in the family Lyctidae in addition to those named above that infest seasoned hardwoods. Adult lyctid beetles range in size from 1/32- to 1/4-inch long. They are red-brown to brown or black in color, and their prominent head is easily seen from above. The last two segments of their 11-segmented antennae are expanded into a club. The tibiae, which are the fourth leg segments, have prominent spurs.

Click picture to enlarge The larvae are tiny C-shaped grub-like larvae found feeding in tunnels in the wood. They are usually less than 1/4-inch long, with an enlarged first body segment (prothorax) and eight spiracles (breathing holes) in the abdomen. The last spiracle is very large compared to the others. These larvae have three-segmented antennae and three segments legs.

Biology: Adult females lay 15 to 50 eggs soon after mating deep within the pores of these hardwoods. Larvae feed on the wood for two to nine months, then they migrate to near the wood surface and pupate. The development time depends on the wood's starch content. They do not infest wood with less than three percent starch content. When development is complete, the adult emerges through a round hole, 1/32- to 1/16-inch in diameter, in the surface of the wood. Development (egg to adult) usually requires nine to twelve months but it can be as long as two to four years, or, in the South, as short as three to four months.

Habits: Lyctid powderpost beetles infest the sapwood of seasoned hardwoods including oak, hickory, ash, mahogany, and bamboo. The eggs are never deposited, waxed, varnished, and painted surfaces, also damaged items with these type finishes must have been infested before they were finished and/or the eggs were laid on an unfinished surface, such as underside of a table or chair. They can re-infest the same piece of wood until it is reduced to a shot-hole riddled shell filled with frass the consistency of the face powder. The wood moisture content suitable for larval development is 8 to 32% but is ideal at 10 to 20%. Adults are active at night and are attracted to light.

Control: Prior to initiating any treatment it should be determined if the infestation is active. Infestations are first noticed when small, "bird shot" size holes appear in the wood and very fine powder-like frass falls from the holes and accumulates in piles under the infested item.

If practical, infested wood can be removed and replaced. Small items not susceptible to cold or moisture damage can be placed in a freezer foe several days at 0 F. Infestations in lumber can be eliminated by fumigation or kiln drying and prevented by treating raw lumber with protective sprays. The lumber used in floors or furniture can be protected with varnishes, waxes, and paints.

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