However, worker termites will continually seek a way to get past this layer and gain access to the wood of the structure. A colony of hundreds of thousands of workers may have food being gathered from dozens of locations at the same time, and the workers are looking for new sources continually. Even when a perfect chemical treatment is done, the chemical does not last forever. In fact, since the elimination of some of the excellent products, such as chlordane, the termiticides available for the professional industry today last anywhere from 5 to 15 years. They degrade under the influence of conditions such as heat, moisture, exposure to sunlight, etc., and disappear from the soil, leaving the home unprotected once again.
Termite baits work because they are providing a food to the termites.
Workers which have discovered the bait return it to the colony, and over time the colony is destroyed as more and more of the workers, as well as the primary and supplementary Queens, eat the bait. Recent field studies by the University of California seem to confirm that entire colonies of termites may actually be eliminated. There is nothing that actually attracts termites to the bait tubes - they simply stumble upon it as they forage here and there for new food sources. Therefore, there really is no guarantee that the bait tubes you place in the ground will be found by termites. An analogy might be that if we were to place a blindfold on someone, and ask him to find a basketball set on a gymnasium floor, eventually he will.