UF Entomologist Develops Safe, Effective Alternative To Deet Insect Repellents

June 29, 1999

GAINESVILLE—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,” said Jerry Butler, entomologist with 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.”

He said the new repellent is a “green” product because it’s an oil extracted from plants that have a natural ability to protect themselves against feeding insects.

The active ingredient in Butler’s new herbal repellent is geraniol, derived from lemon grass and other plants. The product has been labeled “generally regarded as safe” by the Environmental Protection Agency. 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.

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, higher rates of DEET are still used in military applications (31.58 percent).

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, he said.

New label instructions to ensure the safe use of DEET products have been issued by EPA following a review of the most recent health and safety data on this chemical repellent. Based on its review, EPA has determined DEET, if used as directed, will not pose significant health risks to consumers. However, EPA is requiring changes to current labels to ensure DEET is applied safely, particularly on children.

“When these requirements are fully implemented, companies that make and distribute DEET products will no longer be able to claim their products are ‘child safe,’ and new labels will direct parents not to allow children to handle this product,” said Marcia Mulkey, director of EPA’s Office of Pesticide Programs.

She said new directions also will instruct consumers to avoid using DEET products under clothing, to avoid over application, to wash treated skin with soap and water after returning indoors and to wash treated clothing.

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.

Lyme disease is transmitted by the common black-legged tick while the lonestar tick (with a bright star on it) transmits a disease called Granulocytic Ehrlichiosis. Rocky mountain spotted fever is transmitted by the American dog tick, which actually is more common in North Carolina than the Rocky Mountains.

Since 1985, Butler’s research has been supported by grants from International Flavors and Fragrances in Union Beach, N.J., which provides ingredients to the cosmetics industry. The industry has long sought natural repellents for use in various skin-care products. He said some ingredients now used in products actually attract insects.

Butler’s geraniol repellent is patented by UF and licensed to Naturale, Ltd., Great Neck, N.Y., which is marketing the products under the registered trademarks of MosquitoSafe, TickSafe and FireantSafe.