Researchers Aim To Keep Termites From Gorging On Florida Homes

You shouldn't. The tiniest home invaders of all can still get in, sayUniversity of Florida researchers who are studying subterranean termites.

"Most homeowners have a false sense of security that they're protected fromtermites with the barrier treatments that have been popular in the last 10years," said Tom Powell a graduate researcher at UF's Urban EntomologyLaboratory. "But in the real world, there are often gaps in the treatmentbarrier that leave termites a path to your home."

With up to two out of three Florida homes built since 1988 experiencingtermiticide failures, controlling the little home-breakers might seem alost cause. But researchers hope to use new findings to thwart them, saidPhil Koehler, an entomologist with UF's Institute of Food and AgriculturalSciences who is supervising Powell's research.

"Since 1988, termite repellents have been used widely in an attempt tocreate a barrier underneath and around homes. The thought was that atermiticide had to be repellent to protect a house," Koehler said. "Theproblem with this approach is that there are almost always gaps in thetreatment. Termites who are repelled by a termiticide at one spot will turnaround and keep foraging for access to your home and keep trying until theyfind a gap."

The problem with repellents is that they do exactly what they are designedto do -- repel termites. A better approach is to kill termites, saidKoehler and Powell.

Powell has been researching termiticide failures in a unique test oftermite behavior around barrier treatment gaps. In his findings, whichfollow, imagine that "home" is your own home.

In the laboratory, Powell filled eight, flat containers with soil andtreated middle portions with various termiticides, both repellent andnon-repellent. On one side of the treated soil he placed a wooden block torepresent a home. On the other side of the treated soil, he introducedtermites.

When he treated the soil with repellent termiticides to represent barriertreatments, the termites found the gaps and reached the "home" in anaverage of 30 days.

To replicate real-world conditions, in which a pipe could be laid after atreatment thereby creating a gap, he inserted objects in the gaps. In thoseexperiments, the termites reached "home" in an average of just four days.

In experiments using non-repellents, however, there was 100 percentmortality of the termites in 15 days -- and they never reached the "home."

"A repellent is toxic to the termites if they contact it -- in fact, moretoxic than non-repellents -- but they will never come into contact with itbecause they can detect it and avoid it," Powell said. "They don't detect anon-repellent, though, so even if they do find a gap, chances are that theyhave also tunneled into the treatment and contacted enough to kill them."

Non-repellents kill termites when they orally manipulate the treated soilduring their foraging behavior. Currently, six of eight termiticides on themarket are repellents, but Powell said he believes the market will shifttoward non-repellents.

Termite treatment and damage costs $500 million a year in Florida alone. Itbecame an issue in the last decade following a ban on chlordane in 1988,Koehler said.

Chlordane, a non-repellent, was the gold standard in termite protectionbecause it did the job and had staying power. Too much staying power forthe U.S. Environmental Protection Agency. With residual properties lasting35 to 40 years, chlordane's asset became its downfall, and the EPA bannedit because of concerns about excessive human exposure in some houses and insome types of construction.

Homes treated with chlordane in the 1980s have residual protection to relyon. But homes built since 1988 have had to rely on less effectivetermiticides. With as many as 118,000 new homes going up each year inFlorida, that's three squares a day for a lot of termites.

"In houses built since 1988, there has been a very high incidence oftermiticide failures. It's a very real problem," Koehler said. "We've beenlooking at a phenomenon, that when a house is built, up to two of threewill have failures. I've seen 2-year-old houses with $20,000 in damage."

Koehler, who headed up a legislative pest control study committee in 1997,said new building codes are needed to protect homeowners. He suggests aSt. Johns County code as a model because it eliminates food sources thatattract termites and eliminates hidden access. It also requires down spoutsto discharge rain water at least five feet from a building and provides a$50,000 warranty for the homeowner after all precautions are taken.

"Construction practices now allow termites to enter without being seen bythe homeowner," Koehler said. "We need to prevent access from being builtinto a person's home. This is a problem that can be corrected."

Koehler said subterranean termites are the most destructive insect in Florida.

"Several termite colonies can feed on a house at one time," he said. "Someof these subterranean colonies are equivalent to a 50-pound animal eatingup to one pound of wood each day."

Most homeowners don't even know what a termite looks like, Powell said, butwith colonies averaging 250,000 termites each homeowners would be advisedto become acquainted with their subterranean neighbors.

Homeowners who are relying on repellents can take some consolation in arequirement that the treatment last five years, Powell said.

"But," he said, "the best protection is a dead termite."