Click
here for photo lyctid beetles.
Click
here for photo powder post beetle damage.
Although wood infestations
characterized by small holes and frass are usually referred to as powerpost
beetle. The true powder post or lyctid beetles infest only hardwoods.
The main culprits
infesting softwood are usually anobiid
beetles.
In most cases they
are a nuisance pest since it takes many years of activity for anobiid beetles
to structurally damage. Since anobiid beetles prefer moist wood, moisture
elimination should be a part of any control program.
The adult Lyctid
powderpost beetle is a small (1/32-1/4 inch-long), cylindrical, brown beetle
that attacks hardwood. Damage caused by the powderpost beetle is usually
first detected with the appearance of holes in wood, 1/32 - 1/16 inch-diameter,
from which a very fine sawdust may fall. Larvae of the powderpost beetle
feed on many of the various hardwoods used in furniture, baskets, hardwood
trim and flooring. Infestations in homes are almost always due to infestation
of the wood prior to construction.
Powderpost beetles
pass through four distinct life stages: egg, larva, pupa and adult. The
larva is a creamy white, C-shaped grub with an enlarged thorax. The larval
stage of the beetle is responsible for most of the actual feeding damage
to the wood. The life cycle of a powderpost beetle normally requires about
one year; however indoors, powderpost beetles may require two or more (possibly
up to five) years to complete their development and emerge from the wood.
For this reason, infestations may not be detected for several months, or
even years, after completion of a new home.
The most commonly
infested woods include ash, oak, hickory and walnut. Although powderpost
beetles pose little threat to the structural integrity of most homes (which
are framed with softwood lumber, thus not susceptible to attack), it is
a reportable wood destroying beetle and can affect property resale value.
It is also possible, though unlikely, that such an infestation could spread
to hardwood furniture, trim, paneling, or flooring if left untreated. Powderpost
beetles usually require unfinished wood (no paint or varnish) in which
to lay their eggs. Female beetles emerging from infested wood search for
a mate, and then lay their eggs on a suitable piece of wood. The most common
site for egg-laying appears to be exit holes from which the females have
emerged. In this way beetles can reinfest finished wood. Infestations can
also spread to adjacent wood as larvae chew their way from one piece to
another.
Source:Department
of Entomology, Texas A&M University
Links:
Controlling
Wood-Boring Beetles in Houses Pictures
Insects
that Reinfest Structural Woods
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