Bug bombs do a crummy job of killing cockroaches, study finds

Jan. 28 (UPI) -- Trying to get rid of cockroaches? New research suggests commercial bug bombs are unlikely to offer much relief.

When entomologists at North Carolina State University tested four commercial bug bombs in different apartment complexes, they measured minimal changes in resident cockroach populations. The bug bombs did, however, leave toxic residues on apartment floors and countertops.

"All the fogger products contained pyrethroids, a class of fast-acting insecticides, and some contained piperonyl butoxide, a chemical that prevents roaches from metabolizing, or breaking down, the insecticide," Coby Schal, professor of entomology at NC State, said in a news release.

In other words, bug bombs are more likely to expose human residents to harmful chemicals than kill cockroaches.

For the study, scientists surveyed infestations of German cockroaches, Blattella germanica, in 20 homes. Scientists deployed each of the four different types of commercial bug bombs in five apartment complexes. Researchers surveyed pest population numbers two weeks and one month after the fogger release.

Cockroach numbers in all 20 homes were unaffected.

"The bug-bomb products did absolutely nothing to control cockroach populations in these homes," said Zachary DeVries, an NC State postdoctoral researcher.

Scientists published the results of their bug bomb tests this week in the journal BMC Public Health.

In addition to surveying cockroach population numbers, researchers also tested insecticide concentrations on different apartment surfaces in the waKe of the fog release.

Several hours after detonating the bug bombs, scientists measured 600 fold increases in insecticide concentrations on apartment floors and countertops. One month later, insecticide levels were still 34 percent greater than baseline levels measured before the bug bombs were deployed.

"Bug bombs are not killing cockroaches; they're putting pesticides in places where the cockroaches aren't; they're not putting pesticides in places where cockroaches are and they're increasing pesticide levels in the home," DeVries said. "In a cost-benefit analysis, you're getting all costs and no benefits."

In follow up tests, scientists tested two different gel baits -- one commercially available and the other professional-grade -- in five homes each. Applied with a syringe, the gel baits target places where cockroaches are likely to hide. The gels were effective at reducing cockroach numbers in all 10 homes.