Catnip oil may repel mosquitoes better than spray

Scientists aren't sure why mosquitoes hate the smell of catnip.

By Kate Tobin
CNN Science and Technology

CHICAGO, Illinois (CNN) -- Worried about getting West Nile Virus, encephalitis, or some other nasty disease spread by mosquitoes? You may some day find relief in oil that can be extracted from catnip.

New research presented at the meeting of the American Chemical Society indicates nepetalactone (pron. nep-PEET-all-ACT-tone), the oil in catnip that gives it a distinctive minty odor, is a highly effective mosquito repellent.

The research was conducted by Chris Peterson and Joel Coats at Iowa State University. The scientists put 20 mosquitoes in a two-foot-long tube -- half of which was treated with the catnip oil.

After 10 minutes, only 20 percent of the mosquitoes (about four of them) remained on the treated side. In a similar test with DEET, the popular mosquito repellent, 40-45 percent of the mosquitoes remained on the treated side.

But don't look for catnip oil products on store shelves yet. The experiments that have been done so far are preliminary and did not involve testing the oil on humans or animals.

No such tests are currently scheduled, but the Iowa State University Research foundation did file a patent application for the use of catnip compounds as insect repellents.

As for why mosquitoes seemingly hate catnip, the scientists can't really say.

"It might simply be acting as an irritant or they don't like the smell," said Peterson. "But nobody really knows why insect repellents work."