UF Entomologist Develops DEET-Free Insect Repellents

After 15 years of tests on more than 3,900 compounds, a University of Florida researcher has developed a safe, natural insect repellent that protects people against everything from mosquitoes and ticks to tiny "no-see-ums."

"It's the first effective alternative to products containing DEET, the most widely used active ingredient in insect repellents now on the market," says entomology and nematology Professor Jerry Butler of UF's Institute of Food and Agricultural Sciences. "After relying on DEET-based products for more than 40 years, this is a breakthrough that should revolutionize the market."

The active ingredient in Butler's new herbal repellent is geraniol, an oil derived from lemongrass and other plants that have a natural ability to protect themselves against feeding insects. Applied to the skin, it provides almost four hours of protection against a wide range of biting insects, including flies, fire ants, mosquitoes, ticks and biting midges, often called no-see-ums. UF holds a patent on Butler's technology.

Since 1985, Butler's research as been supported by grants from International Flavors and Fragrances in Union Beach, N.J., which provides ingredients to the cosmetics industry. The company elected not to market Butler's product, but with its cooperation the university licensed the technology to Naturale, Ltd. of Great Neck, N.Y. Naturale is marketing the repellent under the registered trademarks of MosquitoSafe, TickSafe and FireantSafe.

Safety concerns over DEET (N,N-diethyl-meta-toluamide) prompted Butler's search for natural, nonchemical alternatives. Toxicity problems, particularly for children and some adults, have forced manufacturers to reduce the amount of DEET in various products to 7 percent from 100 percent during the past 15 years. However, rates of more than 30 percent are still used in military applications.

As levels in consumer products have gone down, the effectiveness and longevity of DEET-based products also have been reduced. Currently, there are more than 60 DEET-based repellents on the market, Butler says.

Butler said DEET is effective against mosquitoes for four to eight hours, but it is not as effective against ticks, fire ants and biting flies. A separate insecticide is needed to control ticks, and it can be applied only to clothing, not to skin.

He said his natural repellent can be applied directly to skin as a treatment against ticks. This reduces their chances of biting and feeding long enough to transmit disease.

Jerry Butler, jfb@gnv.ifas.ufl.edu

Chuck Woods