The usual first sign of a subterranean termite infestation is the appearance of the swarmers, or dis-
covery of the discarded wings, usually on a window sill or other lighted area. Another common
sign is the presence of shelter tubes (Figure 4-14) constructed over foundation walls or piers, in
crevices between structural members or on infested wood. When active infestations or shelter tubes
are damaged, termites will promptly appear (Figure 4-15). Shelter tubes are used as a means for the
termites to move from their nest in the soil to wood located above ground. These shelter tubes are
made from particles of soil or wood and bits of debris held together with fecal material. The tubes
do not conduct moisture, but rather serve to protect the termites from enemies and allow them to
return to the soil.
The only other visible sign of an infestation is the presence of dark spots or blister like areas on
flooring, trim or framing members. These areas are easily crushed with a knife or screwdriver. In
cases of severe damage, a wood member might be partially collapsed at bearing points or otherwise
failed. Internal damage can sometimes be determined by probing the wood with a sharp instrument
or by pounding with a hammer to detect hollow areas.
Several methods may be used to prevent and control subterranean termites. Pressure treatment of
the wood with preservatives is one method of control. Therefore termites are usually not a problem
in preservative treated poles, piles, railroad ties, heavy timbers and lumber unless they gain access
through the protective preservative shell.
Treatment of the soil under and around the foundation with an approved insecticide is probably the
most important step which can be taken to protect buildings. Good design and construction prac-
tices should also be followed. Untreated wood should be at least eight inches from the soil line and
definitely not placed in contact with the soil. Earth-filled porches, flower planters, etc., should not
be attached directly to the house. Wood debris should not be left or buried under or near the house.
Where termites are a serious problem (Figure 4-16), a yearly inspection should be carried out.
Heavy damage from native subterranean termites is not likely to occur for the first five years after a
house is constructed. When termites are found there is no reason for making hurried decisions. Sub-
stantial additional damage will not occur if treatment follows within six months.
22.214.171.124 Formosan. The Formosan subterranean termite has spread from the Far
East to Hawaii, numerous other Pacific islands, California, Texas and to locations in the
southeastern United States. It is expected to spread within its current range. This particular species
is more vigorous and aggressive than the native American species and it is more tolerant to soil in-
The Formosan termite differs from the native species in several features. The Formosan swarmers
are larger in size (up to 5/8 inch long), yellow-brown, have hairy wings and swarm between dusk
and midnight. The Formosan soldiers have an oval-shaped head with a conspicuously enlarged
opening on the top from which a whitish, sticky substance is exuded. Their head is quite different
when compared to the oblong and rectangular heads of the native species (Figure 4-17). The nests