LYCTINE POWDERPOST BEETLES
Common Name: Lyctine (Lyctid) or true powderpost beetles
Scientific Name: Family Bostrichidae (prev. in Family Lyctidae) Tribe Lyctinae
Introduction. Lyctine / lyctid (true) powder post beetle larvae produce a very fine, powder-like frass in their galleries (versus other wood-destroying beetles, whose larvae produce coarser frass which also contains fine wood fragments or pellets). They are worldwide in distribution, with about 11 species occurring in the United States, seven of which have been associated with wood structures and objects.
Recognition. Lyctine / lyctid powderpost beetle adults measure 1/16 to 3/16 inch long, depending on the species. These beetles are elongate, narrow, flattened, almost parallel-sided, and reddish-brown to black in color. The antennae have an abrupt 2-semented club and the elytra (hardened front wings or wing covers) are usually covered with rows of hairs (setae). Depending on the species, the mature larvae range up to about 1/4 inch long and are nearly white. The body is C-shaped with an enlarged thorax and 3 pairs of minute legs.
Similar Beetles. A number of beetles are like lyctid powderpost beetles in size and color. Therefore, a pest control professional or entomologist should be consulted for proper identification of specimens.
Damage and Signs of Infestation. Beetle exit holes are round, and depending on the species, range from 1/32 to 1/16 inch in diameter. Another indication of an infestation is the accumulation of piles of very fine powder-like dust beneath the exit holes of on the wood. This dust (frass) contains no pellets (unlike anobiid frass) and falls easily from the hole instead of being packed in.
Biology. Female lyctid powderpost beetles lay their eggs (15 to 50) in exposed wood pores, cracks or crevices. Eggs are never deposited on waxed, polished, painted, or varnished surfaces. The larvae tunnel only in the sapwood and usually tunnel with the wood grain. As they bore, the larvae loosely pack their tunnels with very fine powder-like dust (like talcum powder or flour). After several molts requiring 2 to 9 months, the mature larva bores to near the surface and constructs a pupal chamber and pupates. When the adult emerges, it bores straight to the wood’s surface and exits. Indoors, adults usually emerge in late winter or early spring and with little feeding, mate. Under very favorable conditions, developmental time (egg to adult) usually requires 9 to 12 months, but may be as short as 3 to 4 months or as long as 2 1/2 to 4 or more years. Although some lyctids are strong fliers, most tend to lay eggs in the wood from which they emerged. Since lyctid larvae cannot digest cellulose, they feed only on the cell contents, which is primarily starch, but also sugar and protein.
Habits. Lyctids attack the sapwood and only that of hardwoods, usually less than 10 years old. They attack both lumber and manufactured products; they also attack structural timbers but hardwoods are rarely used for this purpose today because of their cost. The wood moisture content required for beetle development is 8 to 32%, with greatest activity at 10 to 20%. Adults are active at night, readily fly, and are attracted to light. Lyctids are usually brought into houses and other buildings via infested wood, which contains their eggs and/or larvae. This wood is typically infested during drying time or storage. An applied finish on wood prevents egg lying.
These beetles usually attack oak, hickory, walnut, maple and ash, but will attack other native and tropical hardwoods. Lyctids often attack bamboo.
Cultural Control & Preventative Measures. The easiest way to prevent infestation of buildings and wood furnishings by lyctid powderpost beetles is to thoroughly inspect old wood items for signs of beetle damage (such as 1/32 to 1/16 inch diameter holes and powdery frass) before bringing them inside. This includes antique furniture, barn wood (e.g., beams and siding intended for use as rustic mantles for fireplaces and paneling for a recreation room). If old barn wood is desirable for a rustic decor, it should first be treated by a pest management professional, either by application of an aqueous borate preservative or by chamber fumigation.
Professional Control. A Rottler pest management professional will be able to determine whether or not a powderpost beetle infestation exists and whether the evidences indicate current or past activity. If beetles are active in woodwork, a borate treatment of exposed structural wood can be contracted and performed. Some items can be heated to 140oF for 40 minutes to control lyctids.
Note: Aqueous borate treatments are not applicable to finished antique furniture, nor effective if the infested structural wood is finished with paint, varnish, shellac, wax, etc. A chamber fumigation may be arranged for treatment of valuable antique furniture if the situation warrants it and all conditions are met.
Lyctid powderpost beetle exit holes measure 1/32 – 1/16 inch across.
Locations
Serving the St. Louis Metropolitan area since 1956, including
Arnold, Ballwin, Chesterfield, Crestwood, Creve Coeur, Des Peres,
Fenton, Florissant, Kirkwood, Maryland Heights, Overland, St.
Charles, Webster Groves, Wentzville and surrounding areas.
In Illinois: Belleville, Collinsville, Edwardsville, Columbia,
Madison, Waterloo, O’Fallon, Granite City, Alton, St. Clair, Monroe
and surrounding areas.
Columbia & Jefferson City, MO and surrounding areas.
