Key West, and to the islands of Hawaii. They also are a lo-
calized problem in Arizona and New Mexico.
The nonsubterranean termites, especially the dry-wood type,
do not multiply as rapidly as the subterranean termites and
have a somewhat different colony life and habits. The total
amount of destruction they cause in the United States is
much less than that caused by the subterranean termites. The
ability of dry-wood termites to live in dry wood without out-
side moisture or contact with the ground, however, makes
them a definite menace in the regions where they occur.
Their destruction is not rapid, but they can thoroughly riddle
timbers with their tunneling if allowed to work undisturbed
for many years. Nonsubterranean termites are often moved
from structure to structure in infested items such as
furniture.
In constructing a building in localities where the dry-wood
type of nonsubterranean termite is prevalent, it is good
practice to inspect the lumber carefully to see that it was not
infested before arrival at the building site. If the building is
constructed during the swarming season, the lumber should
be watched during the course of construction, because in-
festation by colonizing pairs can easily take place. Because
paint is a good protection against the entrance of dry-wood
termites, exposed wood (except that which is preserva-
tive treated) should be kept covered with a paint film. Fine
screen should be placed over any openings to the interior
unpainted parts of the building. As in the case of ground-
nesting termites, dead trees, old stumps, posts, or wood
debris of any kind that could serve as sources of infestation
should be removed from the premises.
If a building is infested with dry-wood termites, badly dam-
aged wood should be replaced. If the wood is only slightly
damaged or is difficult to replace, further termite activity
can be arrested by injecting a small amount of an approved
pesticidal dust or liquid formulation into each nest. Current
recommendations for such formulations can be found from
state pest control associations. Buildings heavily infested
with nonsubterranean termites can be successfully fumigat-
ed. This method is quicker than the use of poisonous liquids
and dusts and does not require finding all of the colonies.
However, it does not prevent the termites from returning
because no poisonous residue is left in the tunnels. Fumiga-
tion is very dangerous and should be conducted only by li-
censed professional fumigators. Infested pieces of furniture,
picture frames, and other small pieces can be individually
fumigated, heated, or placed in a freezer for a short time.
In localities where dry-wood termites do serious damage
to posts and poles, the best protection for these and similar
forms of outdoor timbers is full-length pressure treatment
with a preservative.
Naturally Termite-Resistant Woods
Only a limited number of woods grown in the United States
offer any marked degree of natural resistance to termiteit is a good precaution to cap the foundation with 100 mm
(4 in.) of reinforced concrete. Posts supporting floor girders
should, if they bear directly on the ground, be of concrete.
If there is a basement, it should be floored with concrete.
Untreated posts in such a basement should rest on concrete
piers extending a few inches above the basement floor.
However, pressure-treated posts can rest directly on the
basement floor. With the crawl-space type of foundation,
wood floor joists should be kept at least 460 mm (18 in.) and
girders 300 mm (12 in.) from the earth with a polyethylene
vapor barrier covering exposed soil and extending partially
up the foundation wall. Moisture condensation on the floor
joists and subflooring, which may cause conditions favor-
able to decay and contribute to infestation by termites, can
be avoided by covering the soil below with a moisture barri-
er and assuming proper drainage of rainwater away from all
sides of a structure by managing rain and roof runoff with
gutters, downspouts, and proper grading around the founda-
tion. All concrete forms, stakes, stumps, and wastewood
should be removed from the building site because they are
possible sources of infestation. Generally, the precautions
effective against subterranean termites are also helpful
against decay.
The principal method of protecting buildings in high ter-
mite areas is to thoroughly treat the soil adjacent to the
foundation walls and piers beneath the building with a soil
insecticide. When concrete slab floors are laid directly on
the ground, all soil under the slab should be treated with an
approved insecticide before the concrete is poured. Further-
more, insulation containing cellulose that is used as a filler
in expansion joints should be impregnated with an approved
chemical toxic to termites. Sealing the top 13 mm (1/2 in.)
of the expansion joint with roofing-grade coal-tar pitch also
provides effective protection from ground-nesting termites.
Several soil treatments and insecticidal bait control meth-
ods are currently available. Information on current control
methods is available from national pest control operator as-
sociations. These organizations should be consulted to take
advantage of the latest technology in termite control.
To control termites already in a building, contact between
the termite colony in the soil and the woodwork must be
broken. This can be done by blocking the runways from soil
to wood, treating the soil, repairing leaks that keep wood
within the structure wet (for example, plumbing leaks), or
some combination of these techniques. Possible reinfesta-
tion can be guarded against by frequent inspections for
signs of termites.
Nonsubterranean Termites
In the United States, nonsubterranean termites have been
found only in a narrow strip of territory extending from cen-
tral California around the southern edge of the continental
United States to Virginia (Fig. 14–9) and in the West Indies
and Hawaii. Their principal damage is confined to an area
in southern California, to parts of southern Florida, notably
General Technical Report FPL–GTR– 190