beetles emerge. The circular emergence holes and longitudinal galleries are 1/32 to 1/16 inch in
diameter (Figure 4-22). Small piles of fine flour-like wood or frass can be found on or under the
wood. The frass is loosely packed and a slight jarring of the wood will make the frass sift from the
holes. With severe infestations, the sapwood may be completely converted to frass held in by a
very thin veneer of surface wood with beetle exit holes. With heavy infestations, parasitic wasps,
which make circular holes larger than those of the beetle, may be seen.
Bostrichids are also called false powder post beetles, or large powder post
beetles to distinguish them from the lyctids. Because they naturally infest dead or dying branches,
they are also called branch and twig borers. These beetles are of less importance in wood products
than are anobiids or lyctids. These insects normally do not reinfest wood, but one generation can do
substantial damage in some cases.
Most species prefer the sapwood of hardwoods but a few attack conifers. The wood may be freshly
cut, partially seasoned or relatively dry, and have the bark on. The beetles digest primarily the
starch, thus their activity is predominately in the outer sapwood.
The species which attack freshly sawn softwoods usually reach maturity in one year, but may re-
quire five years if the wood dries rapidly. They are found primarily when bark edges have been left
on the lumber.
The first signs of infestation are the 3/32 to 9/32 inch entry holes. The exit holes, which are similar
to the entry holes, are often filled with frass. The frass is meal-like and tightly packed in the gal-
leries and contains no pellets like those of the anobiid. Consequently, the frass does not sift out of
the wood easily.
The interior of the sapwood may be filled with very round tunnels ranging in size from 1/16 to 3/8
inch in diameter, depending on species (Figure 4-23). In extreme cases, the sapwood may be com-
pletely destroyed. Damage can occur much more rapidly than with the anobiids. However, only the
outer part of the sapwood is destroyed, and damage will not extend more than one or two inches
into a board.
Cerambycids are one of the largest and most important family of wood boring
beetles. They are found throughout the United States. Two groups of insects within this family will
be discussed. These are the long-homed beetles, or round-headed wood borers, and the old-house
The long-horned beetles derive their name from the mature beetle
having antennae longer than half their body length. The larvae are described as roundheaded wood
borers, presumably due to the circular emergence holes (Figure 4-24). This group should be recog-
nized because they may emerge after the wood is put into service or their damage may be mistaken
as evidence of an active infestation of the powder post beetles.