Carbon dioxide can combat termites.

A safer and cheaper way to prevent termites from infesting homes, where they cause an estimated $750,000,000 in damage in the U.S. annually, may result from a discovery by entomologist Louis Bjostad, Colorado Stare University, Fort Collins. He found that termites' natural reliance on carbon dioxide to find food and shelter can be used against the insects as a nontoxic alternative to current forms of pest control. "When we first initiated the experiments, we wondered if the concept would be too simple to work," he notes. "Our findings show that carbon dioxide undoubtedly attracts termites, which opens up a whole range of possibilities for controlling these pests."

Bjostad, with researchers Elisa Bernklau and Erich Fromm, made the discovery by placing two types of termites--Reticulitermes tibialis, a species common to Colorado, and R. flavipes, a frequent pest in the Great Lakes--at one end of a T-shaped tube. In one arm, researchers pumped in normal air; in the other, [CO.sub.2] in concentrations higher than those found in normal soil. "When a termite came to the point of choosing an arm, it moved its antennae to one side of the tube, then the other," Bjostad indicates. "Most of them chose the side containing the carbon dioxide."

The scientists believe termites are attracted naturally to carbon dioxide for two reasons. Rotting wood--their main source of food--releases [CO.sub.2], a process that likely guides the insects to food...