Title: formosan subterranean termite
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Title: formosan subterranean termite
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Creator: Su, Nan-Yao.
Publisher: Fort lauderdale Research and Education Center, IFAS, University of Florida
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Fort Lauderdale Research and Education Center



Nan-Yao Su and Rudolf Scheffrahn


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REC Research Report FL 85-1

May 1985

University of Florida-I.F.A.S.
3205 College Avenue
Fort Lauderdale, Florida 33314





Nan-Yao Su and Rudolf Scheffrahn

Fort Lauderdale Research and Education Center
University of Florida-I.F.A.S.
3205 College Avenue
Fort Lauderdale, Florida 33314

I. Introduction

The Formosan subterranean termite, Coptotermes formosanus
Shiraki is a most destructive structural pest wherever it occurs.
Native to China, it has been found in Taiwan, Japan, Guam, Hawaii,
continental U.S., South Africa, and Sri Lanka. During the 1960's it
was found in Texas, Louisiana, and South Carolina. In 1980, a well-
established colony was thriving in a condominium in Hallandale,
Florida (Koehler 1980). Further inspections found 7 condominiums and
1 house infested there. On a 1982-3 survey conducted by C. R. Thompson
(unpublished), the Formosan termite was collected over about 60 sq.
miles covering Broward and Dade county; and of the 40 condominium lots
surveyed, 17 had active infestations. Our 1985 data, however, indi-
cate this figure has grown substantially.
II. Biology

Termites initiate a new colony by sending out winged repro-
ductives (alates) from an established colony. Major swarms of the
Formosan termite occur in May and June on humid, still evenings bet-
ween dusk and midnight. Because alates are attracted to lights, large
numbers can be seen around light sources during a swarm. After a short-
flight, alates drop to the ground, shed their wings and pair off. If
they successfully find a small crevice containing moist wood, the pair
forms a chamber in which eggs are laid. It usually takes 3-5 years to
develop a mature colony. A Formosan termite queen lays approximately
2,000 eggs per day. A matured colony averages 2-3 millions termites
(Lai 1977) and its foraging territory may range up to 300 feet from
the nest (King and Spink 1969, Li et al. 1976, Lai 1977).
III. Destructiveness

The Formosan termite is less selective in feeding than other
native species. It will eat anything containing cellulose. A single
individual of the Formosan termite doesn't consume more wood than

*Use of a trade name does not constitute a guarantee of the product by
the University of Florida and does not imply its approval to the
exclusion of other products that may also be suitable.

native subterranean termites (Su and La Fage 1984a, and b), however,
because of its large population size, a colony of this termite can
cause major structural damage in a short time. In Hawaii, when some
unprotected homes were built over large colonies, records showed that
the Formosan termite caused major structural damage in 6 months and
almost complete destruction in 2 years (Tamashiro 1984). Hawaiian
studies also found that Formosan termites attack at least 47 species
of living plants including sugarcane, avocado, mahogany, banyan, euca-
lyptus, coconut, citrus, and mango (Lai et al. 1983). The Formosan
termite attacks structural lumbers and living plants because they are
sources of cellulose. However, this termite is also known to attack
non-cellulose materials such as plaster, plastic, asphalt, and thin
sheets of soft metal (lead or copper) in search of food and moisture.
Their highly publicized ability to chew through concrete is a fallacy.
However, the Formosan termite is uncanny in finding small cracks in
concrete which they use as foraging routes.
IV. Mode of entry into structures

(1) Ground colony
Formosan termites generally invade structures from the
ground. They commonly enter through expansion joints, cracks and
utility conduits in slabs, and holes for tub drains. Any wood
connecting with the ground is an inviting entrance to this ter-

(2) Aerial colony
Although the Formosan termite is classified as one of the
subterranean termites, it does not always require ground con-
nection. If a pair of alates successfully finds suitable con-
ditions, i.e. adequate food and moisture sources in a
building, they can initiate a colony with no ground connec-
tion. The flat roofs of high rise buildings, because they almost
always contain water, are places for the Formosan termite to
initiate aerial infestations if portals of entry are found.
V. Recognition

(1) Insect identification
Termites are social insects and 3 forms (called castes) are
commonly seen; winged reproductive (alates), soldiers, and
workers. Only alates and soldiers are used for iden-

(a) Alates
Alates of the Formosan termite are yellowish-brown and
12-15 mm long (0.5 0.6 inches). While the Formosan
termite swarms at night, native subterranean termites,
which are black and 10 mm long (0.4 inches), are daytime

fliers. Because the Formosan termite swarms at night and
is attracted to lights, they are found near windows,
light fixtures, window sills, and cobwebs around well
lighted areas. If the insects found fit the above
description (swarm at night, are yellowish-brown and
12-15 mm long), they should be preserved in alcohol
(rubbing alcohol is fine) and sent in for confirmation.
Wings are important for identification and should be
included. If only wings are found, they can be placed in
an envelope and mailed.

(b) Soldiers
Soldiers of this termite have an orange-brown, oval shaped
head and a white body. Because the Formosan termite
colony contains a larger soldier proportion than native
subterranean termites, infestations with many soldiers is
a good indication of its presence. Soldiers should also
be preserved in alcohol for identification.

(2) Signs of infestation
Outside walls and interiors of structures should be inspected
for foraging tunnels made of soil about 1/4 inch wide.
These tubes are usually found tracing expansion joints, in and
around doors and window frames, along siding, or over plumbing
pipes penetrating the slab. Check wood in contact with the
soil. Any wood products should be checked by tapping with a
hard object. A hollow sound suggests infestation. In severe
infestations, this termite hollows out woods leaving a paper-
thin surface. Another characteristic of Formosan termite
infestations is carton nest material that is made of termite
excrements, chewed wood, and soil. Carton nests are usually
found in crevices of structure such as between walls, beneath
sinks, etc.

VI. Control of Formosan termites

(1) Prevention

(a) Chemical control
To stop the termite, the food-moisture-niche triangle
must be broken (Tamashiro 1984). The most common method
is to place a chemical barrier between the termite and
the structure to be protected. Chemicals used are long-
term residual insecticides such as 1% aldrin, 1 or 2% chlor-
dane, 1% chlorpyrifos (Dursban)* or 1 or 1.5% heptachlor.
Preconstruction treatment of soil is easier and cheaper.
Insist that your contractor provide a thorough soil
treatment for Formosan termite. Post-construction treat-
ment can be done by drilling holes through slabs and
injecting insecticides under structures.

In heavily infested areas such as Hallandale, in addition
to these soil treatments, it is prudent to apply an insecti-
cide such as chlorpyrifos to exterior building crevices such
as roof-flashing that may provide a niche for swarmers to
initiate a colony. This will help prevent aerial infesta-

(b) Preventive practice
Use of preservative treated woods during construction or
when replacing damage is highly recommended. Do not
place untreated wood on the ground. The combination of
water and wood or other cellulose materials provide
attractive conditions for the Formosan termite. Correct
any moisture problems in the building. Leaky sinks, air
conditioning condensate, and any portion of the building
that may collect excessive amounts of moisture should be
corrected to insure dryness. Without an adequate water
supply, even the Formosan termite will not survive within
During the swarming season (late April to July) special
precautions should be taken to prevent aerial invasion.
Formosan termites do not swarm every night, but as a pre-
caution windows should be closed or at least screens
should be in place. If possible, lights near windows
should be turned off. This will steer alates to other
lights in the neighborhood.

(2) Remedial control
These methods are used to control active infestations. For
small structures with lighter infestations where termite acti-
vity can be easily detected, spot treatments are less expen-
sive, easy, and effective. A well-trained and experienced
exterminator can locate such infestation sites. The common
belief that this insect is "immune" to all insecticides is
false. Most insecticides will kill Formosan termites if the
chemical can be injected into galleries to reach them. After
the treatment, moisture problems should be corrected, and
infested wood be replaced with treated lumber.
It is extremely difficult to locate all active infestations
in large buildings that contain many hidden infested sites.
If any of these sites are left untreated, termites will sur-
vive and initiate another aerial infestation called a "Type
III" aerial infestation (Tamashiro 1984). If carefully con-
ducted, fumigation can be used to kill the active infestations
within a structure. Fumigation with sulfuryl fluoride
(Vikane*)* gas at a 4X rate over the drywood termite rate or
methyl bromide gas have been used to kill active infestations in
the structures. Fumigants, however, leave no residual protection.
Thus, preventive control with soil treatment should be per-
formed at the same time. Spot treatment is not recommended in

large structures with severe infestations. Most likely such
practice will allow the Formosan termites to survive and require
more frequent and expensive retreatment.
Because of the magnitude of the colony size of this termite,
there is no technique available today to eradicate the entire
colony. Most treatments only kill a portion of the colony.
Recent studies showed that there are promising insecticides
that may be used to eliminate the entire colony (Su et al.
1982, 1984). More research has to be done to develop tech-
niques to make these compounds effective.
If the suggestions made here are followed, however, there is a
good chance that the Formosan termite can be kept away from
buildings. The Formosan termite takes advantage of a pesti-
cide applicator's mistakes and thus is likely to require
retreatment more often than native termites. The exterminator
and the public should be aware that greater care is required
when treating Formosan termite infestations. Because there
are large ground colonies in infested areas such as Hallandale,
homeowners in such areas should periodically inspect or have
their buildings inspected by experienced exterminators.


1. King, E. G., and W. T. Spink. 1969. Foraging galleries of the
Formosan subterranean termite, Coptotermes formosanus
in Louisiana. Ann. Entomol. Soc. Am. 62: 537-542.

2. Koehler, P. G. 1980. The Formosan subterranean termite. Fla.
Coop. Ext. Serv. Circ. ENT-51: 4 pp.

3. Lai, P. Y. 1977. Biology and ecology of the Formosan sub-
terranean termite, Coptotermes formosanus, and its suscep-
tibility to the entomogenous fungi, Beauveria bassiana and
Metarrhizium anisopliae. Ph.D. dissertation, University of
Hawaii, Honolulu.

4. Lai, P. Y., M. Tamashiro, J. R. Yates, N-Y. Su, J. K. Fujii, and
R. H. Ebesu. 1983. Living plants in Hawaii attacked by
Coptotermes formosanus. Proc. Hawaiian Entomol. Soc. 24:

5. Li, T., K. H. He, D. X. Gao, and Y. Chao. 1976. A preliminary
study of the foraging behavior of the termite, Coptotermes
formosanus (Shiraki) by labelling with iodine-131. Acta
Entomol. Sinica. 19: 32-38.

6. Su, N-Y., M. Tamashiro, J. R. Yates, and M. I. Haverty. 1982.
Effect of behavior on the evaluation of insecticides for pre-
vention of or remedial control of the Formosan subterranean
termite. J. Econ. Entomol. 75: 188-193.

7. Su, N-Y. and J. P. La Fage. 1984a. Comparison of laboratory
methods for estimating wood-consumption rates by Coptotermes
formosanus (Isoptera: Rhinotermitidae). Ann. Entomo. Soc.
Am. 77: 125-129.

8. Su, N-Y., and J. P. La Fage. 1984b. Differences in survival and
feeding activity among colonies of the Formosan subterranean
termite (Isoptera: Rhinotermitidae). Z. ang. Ent. 97:

9. Su, N-Y., M. Tamashiro, J. R. Yates, and M. I. Haverty. 1984.
Foraging behavior of the Formosan subterranean termite
(Isoptera: Rhinotermitidae). Environ. Entomol. 13: 1466-

10. Tamashiro, M. 1984. The Formosan subterranean termite. Whitmier
Institute of Technology and Advanced Pest Management. 4 pp.

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