Termite Interceptors

Formosan Termites
In The United States


Summary: The Formosan subterranean termite (FST), Coptotermes formosanus, is a serious structural pest in the U.S. today, not only in the coastal tropics, but inland, wherever it has been imported in infested wood and cellulose products.  Once FST colonies become established, they have rarely, if ever, been eradicated, partly because traditional termite treatment approaches target individual infestations rather than entire termite colonies. Organized treatments of entire infestation zones are capable of eradicating entire FST colonies. In particular, small pockets of FST in areas that are not ideal for their development can be eradicated using aggressive interdiction, interception, and inoculation measures, not only in the structures that are threatened, but in the forested areas nearby.  Such measures should work well, especially if those forested areas are limited to greenbelt strips, as they are in many upscale subdivisions where imported FST colonies have been found in Austin, Dallas, and San Antonio, Texas, and in other states as well.  Scroll down to read full text of of article. 


The Formosan subterranean termite, Coptotermes formosanus (Shiraki) is native to China. It is a serious structural pest wherever it manages to thrive, and today it is found throughout the world excluding the polar regions but including Hawaii and the continental United States.  The species travels well.  Advances in shipping, over the past 150 years, have managed to spread it far and wide. The species arrived in Hawaii as early as 1869, in South Carolina in the mid 1950's (specifically Charleston, according to some authorities, in  1957), and Texas and Louisiana in the mid-1960's (cases were reported in Houston in 1965, and soon afterward in Lake Charles in 1966).

Presently the Formosan termite is found in Louisiana, Florida, Alabama, North and South Carolina, Tennessee, Mississippi, Georgia, Texas, and southern California, including urban areas far from the coasts.  Many entomologists once thought the species would be restricted to a narrow strip of coastland, where it would thrive in the presence of damp maritime breezes and relatively high temperatures, but the Formosan termite has shown amazing adaptability.  Significant extra-coastal infestations have occurred in Atlanta, Memphis, Austin, Dallas, San Diego, and a host of other cities, apparently transported inland in building materials and plant matter.  It seems only a matter of time before it becomes firmly entrenched throughout the southeastern and southwestern states, and our western states bordering the Pacific Ocean.

Once established anywhere, the Formosan subterranean termite has successfully resisted extermination, despite efforts to eradicate it. This termite, like the native subterranean termites that it coexists with, is a cryptic creature that hides its activities from view.  Like other species and genera of subterranean termites, it takes positive steps to mitigate unfavorable  environmental conditions around it, altering them to meet its special  needs. 

Two to seven years are required before a newly introduced Formosan termite colony produces enough external evidence of its presence to be noticed.  Even when such evidence is discovered, the termite may be mistaken for a common native subterranean species if the pest management specialists involved fail to collect specimens and examine them carefully.  Translocated Formosan infestations propagate their colonies much as our native species do.  Initially they infest landscaping and dead and live plants in natural forest and wilderness areas, where their activities go largely unnoticed. Later, as their colonies grow larger and more voracious, they begin to move into residential structures nearby to attack wood inside walls, cardboard facing on sheetrock, and anything containing cellulose or other carbohydrate sources.

In Austin, Texas, many of the known, established Formosan termite infestations are associated with lush greenbelts near upscale residential subdivisions.  Railroad ties or other timbers, some of which were shipped from coastal regions with serious Formosan termite infestations, were used by builders and homeowners for landscaping purposes.  The termites spread from such timbers to surrounding greenbelts as long ago as 1992, when the first Formosan termite infestation was found in Travis county.  Over the intervening years they became so well-established that many authorities doubt they will ever be totally eradicated.  The first swarms from their established colonies probably took place as early as 1995, but many did not occur before 1999.  Because the Formosan termite swarms after dark, those seminal events failed to garner much attention.


Important Notice to Residents of Central Texas

EntomoBiotics Inc. is carrying out a confidential research program to learn more about the distribution of Formosan termites in Texas.  If you believe you live near a location where Formosan termites have been found, we will inspect your home and yard for signs of termite activity and will suggest ways you can reduce the risk of termite infestation.  This service is performed without charge, and our findings are kept confidential to protect your privacy. 

For more information, call 512-331-1111 or email Jerry at the link provided at the foot of this article.

We respect your privacy...


On May 14, 2006, Formosan termites swarmed in a home in an upscale subdivision in northwest Austin.  We collected specimens from the swarm, and examined the damage done to the home.  The termites appeared to have entered the structure on an inside wall through an underground foundation penetration for electrical service.  The Formosan termite colony involved was large and mature, at least five and possibly seven or more years old.  Four other homes in the same neighborhood have been treated for Formosan termites over the past two years, and Formosan termites swarmed in one of those homes the week prior to this incident.  Each of the treated homes either has a huge back yard that contains dense forest, or backs up to a greenbelt.  Formosan termites adapt to such environments naturally. 

The above example is only one of several known infestations of Formosan termites in the Austin area.  It points out the crucial importance of treating not just the structural infestations involving subterranean termites, but diligently searching for and intercepting the infestations in nearby landscaping and forested areas.  That object has directed our research and development of the EntomoBiotic Termite Interceptor, Annunciator, & Inoculator (TIAI).  We know, from years of studying and observing termites all over Texas, that termites can and should be stopped before they get into a home.  Waiting until they infest a structure is waiting too long.

The EntomoBiotic TIAI, in conjunction with our IRIM i3 termite interception, interdiction, and inoculation program, works as well with Formosan subterranean termites as it does with our native termite species.

Interdiction is a crucial part of the IRIM i3 termite interception, interdiction, and inoculation program. Interdiction involves proactively treating residential homes, detached garages, sheds, fences, decks, and the like, to eliminate the risk of termite infestation. If interdiction is carried out properly, structures can be fully protected against infestations of subterranean termites, including FST.  Furthermore, it is now possible to perform a complete interdiction program in the most sensitive places, such as a residential home, using non-chemical, non-toxic products that pose absolutely no risks to humans or their pets, but that provide long-lasting protection against termites.  Interdiction, carried out this manner, goes a long way toward giving homeowners and business owners peace of mind.  However, termite control does not end with interdiction. 

Subterranean termites, including FST, pose risks to much more than the man-made objects around you.  All the trees, shrubs, and other woody herbaceous materials in yards are at risk, too.  If you love your landscaping, you appreciate the value it adds to your home or business.  Protecting that from termite damage and decay is as important--or at least almost as important--as protecting your home or business itself.

Because FST forage underground, and construct subterranean tubes that extend up to 300 feet from the primary brood care locus, it is possible to intercept and inoculate them before they get to a structure.  Placing several Termite Interceptors in the back yards of homes that back up to greenbelts where FST are established has the potential to limit their spread and protect the homes involved. 

Inoculation of Formosan subterranean termite colonies using nematodes is performed as with other termites, and includes injecting the nematodes directly into the workings and/or carton nests of the colony. Those workings or carton nests may be in a landscape plant, a section of timber, or a termite interceptor disposed in the soil. Once that is done, the soil and landscaping near the home can be monitored with additional termite interceptors to prevent new termite colonies from developing.

Formosan termites swarm between May and July, beginning around dusk and lasting until about midnight.  In urban areas, the winged alates may congregate around lights near their swarming sites. Swarmers fly no more than 60-150 feet before the alates discard their wings, mate, and look for a moist place to start a new colony. From a single pair of termites, a mature colony can become sufficiently established to produce its own swarmers within a matter of years. Mature FST colonies may reach, within as few as seven years, a population of 10 million (though the average size is less than 5 million and, in drier and cooler locales found inland the size of each colony will likely average less than 5 million), including workers, soldiers, the primary queen, plus a host of secondary kings and queens fully capable of reproduction. Workers in a mature Formosan termite superorganism often forage as far as 300 feet away from the colony's primary brood care chambers.

This termite attacks living plants as well as structural lumber, a feature that some entomologists point to as distinguishing it from our native termites.  The fact is, however, that our native subterranean termites also attack living plants. Individual Formosan termite workers consume slightly less cellulose per day than our native subterranean termites, but the large number of workers associated with a Formosan superorganism enables mature superorganisms to inflict severe structural damage to unprotected homes in as few as 2 years.

Most of the time, when infesting a structure, the Formosan subterranean termite maintains contact with the soil because that is the most efficient way to maintain the high moisture level needed in the workings of its superorganism. However, if sufficient moisture exists in the structure itself--due to faulty plumbing or roof leaks, for example--the superorganism will sever contact with the soil, forming a strictly aerial infestation. In Louisiana and Florida, up to one quarter of the structural Formosan subterranean termite infestations are strictly above-ground, having no contact with the soil. By contrast, only one in a hundred native subterranean termite infestations of structures are aerial.  The lesson here is that moisture problems in a structure must be attended to, because they may permit aerial infestations of Formosan subterranean termites, or even native subterranean termites, to form.  Such infestations never succeed in areas lacking sufficient moisture, regardless of the subterranean termite species involved.

Formosan termites damage wood in a fashion similar to that done by native subterranean termites, but certain features distinguish one from the other. Formosan workers follow the grain when feeding on lumber but, while the native species avoid wood with a high lignin content, in favor of wood high in cellulose, the Formosan termite feeds on both.  This produces a large hollow space in the lumber they infest, and leads to rapid structural failure of the wood member. 

Another difference is that, while native subterranean termites load their workings with detritus, those of the Formosan termite are clean. Aerial Formosan termite nests--referred to as carton,  are constructed of detritus similar to that found in native subterranean termite workings, but the architecture is more complex and the material is more compact.  Carton nest production, as used by the Formosan termite, is unique to the genus Coptotermes. Such nests are located near the feeding site.  If conditions allow, they may construct carton nests within the feeding site itself.  Individual Formosan termite superorganisms typically construct several auxiliary nests, each of which contain secondary reproductives capable of brood production.

Homeowners can do much to reduce the risk that any subterranean termite species, including the Formosan subterranean termite, will infest their homes.  Moisture problems in a home should be corrected immediately.  That means keeping roofs in good repair, fixing flashing that gets displaced or that was installed incorrectly during home construction, and having all plumbing leaks attended to without delay.  Untreated moisture problems provide termites all the conditions they need to infest a home and inflict serious damage before they are detected. 

Correcting conditions around a home that make inspections of the exterior foundation difficult or impossible is another high priority for the savvy homeowner.  Wood, bricks, or other materials stacked against a house can be a big mistake, because termites can enter the home behind the stacked materials without being seen.  Similarly, soil that extends above an existing brick or masonry ledge will obscure termites entering the house via that route.  And there are more.  The best way to start termite-proofing a home is to call out a professional, licensed in termite control, to have a termite inspection done.  Then, follow the inspector's advice and fix the issues that the inspection illuminates.

Using IRIM i3 termite interception, interdiction, and inoculation, in concert, will protect your home and landscaping from the ravages of termites without exposing you, your family, or your pets to harmful chemicals and toxicants. Termite Interceptors and Inoculators that treat the termites they intercept with nematodes is not a substitute for moisture control inside a home, or for keeping the foundation around a home clear of obstructions, but those measures, when combined with a good interdiction program, minimize the risk of termite damage.