Quantcast Cerambycids -Cont.

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Damage from long-homed beetles usually occurs in fire, disease or insect killed timber which is
being salvaged. The borers damage the wood before it is processed, and activity ceases when the
wood is dried. Many species feed just under the bark before moving into the sapwood, and some-
times the heartwood. Some species may survive for a year or more. Most of the beetles emerge
before the wood is over 1 1/2 years old. During emergence, the borers may cut through plaster-
board, hardboard, hardwood flooring, insulation, roofing felt, shingles, plywood, etc. Since the beet-
les are in the wood only a limited time, serious structural damage usually does not result.
As beetles emerge, they make slightly oval to nearly round exit holes ranging from 1/8 to 3/8 inches
or more in diameter. The species, which are more flattened in cross-section, make oval holes about
twice as wide as high, the widest diameter being about 1/4 inch. In some cases, there is coarse,
even stringy, frass in evidence inside or around the exit holes.
If the damage occurred in the log, the galleries in the sawed lumber may appear oval to elongate
depending on how the saw intersected the galleries. The diameter in true cross-section will vary
with the age of the larva that made the gallery, and with the species involved. Tightly packed, rather
coarse frass may be present in the exposed galleries (Figure 4-24). At other times the galleries are
free of frass because it was loosely packed and has fallen from the wood. If the bark edges have
been left on lumber, there often is much frass in evidence underneath. The texture of the frass
varies from rather fine and meal-like in some species to very coarse and almost excelsior-like in
other species.
The old-house borer is a round headed borer which, unlike most of the
others in this family, is capable of reinfesting wood in use. It probably ranks next to the termites as
a pest of buildings in the eastern United States. The heaviest infestations occur along the Atlantic
seaboard, particularly the mid Atlantic states. It is found in old and new construction, seasoned and
relatively unseasoned softwood lumber, but not hardwoods.
The adult beetle is 5/8 to 1 inch long, slightly flattened, brownish in color with many gray hairs on
its head and the forepart of the body. The hairs are easily rubbed off. The pronatum has a shiny
ridge down the middle and a shiny raised knob on each side. This gives it the appearance of a face
with a pair of eyes. The adult lays its eggs in cracks and crevices in the wood. The larvae hatch in
about two weeks. They are typical round-headed borers up to 1 1/4 inches long. There are three
black eyespots in a row on each side of the small head. The larvae crawl over the surface of the
wood and eventually bore their way into the sapwood. The larvae generally take two to five years
to develop and, in particularly dry wood, they may take 12 to 15 years. A moisture content range of
15 to 25 percent encourages rapid development.
Early infestations are almost impossible to detect since there are no external signs. The larvae,
when boring in the wood, make a rhythmic ticking or rasping sound much like that of a mouse
gnawing. The borers tunnel very closely to the surface but seldom break through. The surface may
bulge out due to packed frass. These bulged or blistered areas are best discovered by shining a light
parallel to the surface. After the adults have emerged, there may be small piles of frass beneath or





 


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