Beetles in the family Lyctidae are known as powderpost beetles. They are so named because larvae leave a fine, dustlike powdered frass (a mixture of feces and food fragments) in their galleries that occasionally falls out of exit holes into small piles on floors or other surfaces. This powdered frass is characteristic of powderpost beetles and helps distinguish them from other typical wood-boring beetles. Lyctids attack hardwoods apparently because these woods have pores into which they can lay eggs; softwoods do not have such pores. Also, the starch content in softwoods is nutritionally low for these beetles. They will attack woods that are very dry (as low as 8% moisture).
Adult lyctids usually range from brownish to reddish in color. Woods most often attacked by this beetle are oak, ash, hickory, mahogany, and walnut; infestations are most likely to occur in wood paneling, molding, window/door frames, plywood, hardwood floors, bamboo articles, and furniture. Infestations may occur if beetles or larvae are brought into a building in furniture or firewood. Sometimes the only sign of infestation may be the tiny, round exit holes made by emerging adult beetles. Once they emerge, the winged adult beetles spread to other wood surfaces where they deposit eggs onto unfinished surfaces or in cracks or other openings.
Adult powderpost beetles (lyctids) are active at night, fly well, and are attracted to light. Female lays (15-50) eggs in exposed wood pores, cracks and crevices, but never on wood that is painted, polished or waxed. The larvae tunnel in sapwood, along the grain, packing their tunnels loosely with very fine, powdery, flour-like dust. After several molts (2-9 months), the mature larva bores back to near the surface to build a chamber and pupate. The adult bores out to the surface to exit, and mates, doing very little feeding. Development time from egg to adult is 9-12 months, but can be as little as 3-4 months, or as long as a few years.
How to Detect True Powderpost Beetles?
Round exit holes, diameter (0.8 to 1.6 mm).
Piles of very fine powdery dust, which falls easily from holes.
Presence of emerging adults.
Wood-boring beetles are difficult to control once an infestation has begun. Prevention is the best management method. Protective measures should be taken at every stage of lumber processing and handling including lumber mills, plywood mills, lumber yards, furniture manufacturing factories, and building construction firms. Sanitation is the most important aspect of prevention. Remove and destroy dead tree limbs around buildings or near any area where wood products are stored. Destroy scrap lumber and other wood products before they become infested. Kiln drying of lumber destroys beetle infestations, although it does not prevent reinfestation. Materials used for construction of buildings and wood furniture should be thoroughly inspected before use to be certain that they do not contain wood-boring beetles. Protect wood from infestation by painting or varnishing to seal pores, cracks, and holes where eggs could be laid, example of the chemical which can be used to protect wood is DTM wood protectant. Chemical control which believed to treat powderpost beetle effectively is deltamethrin. |
