Natural mosquito repellent found

N.C. researcher calls chemical safer and more effective than DEET

July 14, 2002|By Diane Suchetka | Diane Suchetka,KNIGHT RIDDER/TRIBUNE

CHARLOTTE, N.C. - A professor at North Carolina State University says he has discovered a mosquito repellent safer and more effective than DEET, a chemical now used by about a third of the U.S. population every year.

Michael Roe found the natural compound by accident - on the foliage of wild tomatoes that grow in the mountains of Ecuador.

And a Durham, N.C., company is about to begin selling his discovery, under the name "Skeeter Shield."

"Everybody we talk to says, `Oh, my God, this is incredible,'" says Alan Brandt, president and chief operating officer of Insect Biotechnology Inc., which holds the license for use of the compound and will manufacture repellents that contain it.

Mosquito experts across the country say they can't comment until they see results of field data on the substance. Those data haven't been published yet.

A spokeswoman for Clariant Corp., which makes DEET at a plant in Mount Holly, N.C., about 15 miles northwest of Charlotte, declined to comment until the data are out. Clariant, one of two DEET producers in the United States, sells the chemical worldwide.

Name withheld

Biotechnology Inc. isn't releasing the name of the compound until a patent - which has been approved by the U.S. Patent and Trademark Office - is issued, says Brandt.

In tests, people applied the compound to their forearms, then stuck their arms into boxes full of biting mosquitoes. No mosquitoes bit - 12 hours after the compound was applied, Brandt says.

The product also repels ticks, fleas, biting flies, aphids and cockroaches. Brandy says it is natural and biodegradable. The Environmental Protection Agency is evaluating the substance's use as a repellent. Brandt hopes that approval will come in time for it to be in stores before you get your first mosquito bite of 2003.

The main ingredient has been used for years - in cosmetics - so the tests that measure its toxicity are already done, Brandy says.

Roe, the North Carolina State researcher and an expert in bugs, came up with the compound almost two years ago. (It keeps caterpillars away from nonedible wild tomatoes, but isn't found in domestic ones. And it's simple and can easily be synthesized so wild tomatoes won't have to be grown to produce it.) But North Carolina State waited until a patent had been approved to announce the news about the substance - called IBI-246.

DEET is petroleum-based and listed in Toxicity Category III by the Environmental Protection Agency. That means it's "slightly toxic," by EPA standards. And it's been shown to cause rashes, swelling, itching, eye irritation and, in some cases, slurred speech, confusion and seizures.

`Practically nontoxic'

But IBI-246 is in the safest toxicity category - IV - which means the EPA considers it to be "practically nontoxic." None of the problems associated with DEET have been reported on IBI-246, Brandt says, "although we haven't tested it on millions of people either."

Roe, 49, from Louisiana, has taught at North Carolina State for almost 20 years. "The whole discovery was purely accidental," he says. "I don't even work in this area."

He was trying to develop an insecticide when he made the find. Now, he's getting calls from across the country, Canada, even Argentina about the new product. "People called today and asked if they could invest money in this product," he says, sounding surprised.

"People have been looking for a competitive produce to DEET for 20 years," said John Bennett, chairman and CEO of Insect Biotechnology. "I think this is it."

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