Termites have been foraging in (and helping to build) the earth’s soil for 250 million years, so it’s hard to imagine that anything new is happening in their subterranean world. But, here in the United States anyway, there is. The name is Formosan, but the pest-control industry calls them “Super Termites.”

After entering the country through Texas at the end of World War II, the Formosan subterranean termite has established colonies in 14 states, rimming the southern U.S. border from California to Virginia. Formosans are formidable creatures. An average native subterranean termite colony will consume 7 pounds of wood in a year; a Formosan colony will ingest more than 1,000 pounds. This is largely an issue of colony size. Native species seldom develop colonies with a population of more than 1 million, whereas Formosan colonies frequently exceed 10 million.

The Formosan threat is not simply a product of numbers. Unlike native species, which nest in the soil and enter structures only to forage for food, Formosans may establish semipermanent residence in carton nests inside a house. They attack a wider variety of cellulose sources, including furniture, books and living trees. They are also more persistent in finding entry points, often relying on their unique abilities to chew through cement, lead, PVC, rubber and other building materials.

Because they can live semipermanently inside walls, Formosan termites are harder to detect than native subterranean termites, which can be tracked down by the telltale mud tunnels they build on foundation walls to gain access. Both species are easiest to spot in late spring, when the swarmers of each colony fly out from the nest in droves to mate and recolonize.

Termite treatments
Formosan termites cause more than $1 billion in property damage in the United States each year. When added to the damage caused by established native termite species, the tally of termite damage exceeds $3 billion. To make matters worse, most homeowners’ insurance policies do not cover termite damage.

If you live in an area of heavy infestation (see maps) or suspect that termites have found their way into your home, hire a professional inspector to assess the problem and suggest remedies. For information on termite detection, read the home inspection checklist on the Spectracide Terminate Web site (www.homeandgardensolutions.com/pdf/home-inspection-eng.pdf).

The traditional remedy for ongoing termite infestation — and for prevention — has been to inject a large volume (200 gallons or more) of termiticide into the soil around and underneath the home. The termiticide creates a continuous chemical barrier that termites will not cross. This treatment is still used, especially in new construction, but it’s becoming less common. Treatments should be applied only by a licensed pest control operator. They start at about $500 for smaller homes and require reapplication every five to seven years.

Research has helped manufacturers develop new termite-control products and treatments that are effective and friendlier to the environment than chemical barriers. Check with your local building department or municipal home inspector before committing to any treatment, especially if you plan to sell or refinance your home.

Bait stakes
Bait-stake systems are relatively new arrivals on the termite-control scene, but they have taken over a large share of the market, particularly for treating existing homes. Brands vary slightly, but the basic strategy is to drive stakes containing wood bait into the ground at regular intervals around the house. Within a few months, foraging worker termites find the bait and begin to consume it, alerting their fellow workers in the process.

When monitoring reveals that the termites have found the bait (usually a stick of wood), the bait is replaced with a termiticide-laced product. Then foraging termites bring the termiticide back to the nest, where it eventually kills the entire colony. With some products, the workers that consume the bait are killed more quickly, and in time the rest of the colony, which relies on the workers for food, starves.

Bait stakes are more effective and more environmentally friendly than chemical barriers, according to Dow AgroSciences, maker of the Sentricon Termite Colony Elimination System. When used properly, they result in the elimination of the colony, unlike chemical barrier treatments, which only keep termites at bay as long as the barrier remains intact. A bait-stake system requires much less (but more concentrated) pesticide.

Because the bait-and-replace approach requires reliable monitoring, it is most effective when installed by a professional who can determine probable termite entry points. Monitoring contracts — and fees — are required for most product warranties to remain in force. Although installing bait stakes is comparable in cost to chemical barrier treatments, monitoring fees make the total expense higher.

For homeowners who want to take a DIY approach to bait-stake systems, Spectracide Terminate is a consumeroriented product sold by major building centers and retailers. The bait stakes work much like professional versions. You drive stakes into the ground at 10-ft. intervals, 2 to 3 ft. away from the house. The Spectracide bait comes pretreated with poison, so you can skip the step of replacing untreated bait with poisoned bait once activity is found. However, regular monitoring is important because termites will move on to other areas once they’ve eaten the bait. The manufacturer stresses that if termite activity is discovered, the homeowner should call a professional inspector.

Pretreated materials In areas of high infestation, particularly of Formosan termites, some builders and remodelers are turning to pretreated building products. Termites won’t eat lumber or plywood that’s pressure-treated with CCA, ACQ or copper azole. This makes pressure-treated wood a good choice for structural framing, says Dave Mason, director of treated products for the Southern Pine Council.

Materials pretreated with borate, such as SmartGuard building products, are recognized as providing effective termite control by the International Code Council. Boratetreated products are cost-effective and environmentally safe, but because the treating agent is water-soluble, they should be used only in protected areas above ground.

Other treatments
In addition to chemical barriers, baitstake systems and protected building products, a number of other methods and products can help combat termite infestation.

• Sprays and dusts — These products can be applied directly to infested areas for spot treatment. They don’t typically provide complete, long-term protection, but they’re commonly used after detection. Spectracide Terminate makes both a spray and a dust that can be purchased at major retail outlets. Other borate-based sprays, such as Bora-Care, can be purchased through pest-control product suppliers and Internet sites. Spray versions can be used to treat building materials during construction and remodeling.
• Shields — Strip-metal and mesh termite shields can create a physical barrier beneath the mudsill of a house. They offer an added line of defense, but they don’t provide sufficient protection when used alone.
• Sand barriers — Installed around and beneath the foundation slab, sand barriers hold some promise as a natural way to keep termites out. Screened sand particles ranging from 1 to 3 mm dia. are too big for removal by termites but are small enough that gaps between particles won’t allow termites to pass.
• Barrier membranes — One new option for termite protection in new construction is the Impasse polymer membrane (see photo, above). Designed to be rolled out and heat seamed together on the building site before pouring the foundation, the Impasse sheet provides a continuous termite barrier.
• Good housekeeping — Taking simple preventative measures around the home can help to suppress termite activity.

SOURCES
Dow AgroSciences (Sentricon) 800-678-2388, www.sentricon.com
Nisus Corp. (Bora-Care pretreatment) 800-264-0870, www.nisuscorp.com
SmartGuard Protected Building Products 800-585-5161, www.smartguardproducts.com
Southern Pine Council (treated lumber) (504) 443-4464, www.southernpine.com
Spectrum Brands (Spectracide Terminate) 888-545-5837, www.spectracideterminate.com
Syngenta (Impasse) 800-334-9481, www.impasse.com
Terminix (Sentricon operator) 800-837-6464, www.terminix.com