Mosquitoes Repelled By Tomato-Based Substance; Safer, More
Effective Than DEET
A substance produced by tomatoes repels mosquitoes
and other insects more effectively and is safer than DEET, the
chemical most commonly used in insect repellents, a North Carolina
State University scientist has discovered.
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Indeed, work by Dr. Michael Roe, William Neal Reynolds
Distinguished Professor of Entomology at NC State, showed that the
natural compound found in tomatoes is so effective at repelling
insects that the university patented the substance. The patent
describes how the substance may be used to repel insects.
Dr. Michael Roe of NC State with some of the mosquito pests his
tomato-derived substance effectively repels.
The university has since licensed the right to produce the
substance as an insect repellent to Insect Biotechnology Inc., a
Durham company that specializes in developing and marketing
biochemical insecticides. Funding for the research was provided in
part by the National Science Foundation (NSF), the N.C.
Biotechnology Center, the N.C. Agricultural Research Service, and
Insect Biotechnology. Roe's research was also supported by
university overhead receipts.
Roe and Insect Biotechnology Inc. officials believe the
substance, which Insect Biotechnology is calling IBI-246, has the
potential to replace DEET as the active ingredient in most insect
repellents.
"People have been looking for a competitive product to DEET for
20 years," said Dr. John Bennett, chairman and CEO of Insect
Biotechnology. "I think this is it."
DEET (short for N, N-diethyl-meta-toluamide) is a widely used
chemical. The U.S. Department of Agriculture developed DEET for the
Army in 1946. The federal Environmental Protection Agency has
registered approximately 230 products containing DEET, and EPA
estimates that one -third of the U.S. population uses DEET each
year.
While the EPA has found that the normal use of DEET does not
present a health concern to the general population, the use of
products containing DEET has been associated with rashes, swelling
and itching, eye irritation and, less frequently, slurred speech,
confusion and seizures. Products with high concentrations of DEET
are considered hazardous to children particularly, and the EPA no
longer allows claims on labels of products containing DEET that the
product is safe for children.
Recent research at Duke University with rats showed that frequent
and prolonged use of DEET caused brain-cell death and behavioral
changes in the animals.
Roe said that like DEET, IBI-246 repels insects effectively and,
on the scale used by the EPA to gauge toxicity, is considered
slightly safer. He said he discovered the repellent capacity of
IBI-246 by accident.
"I was listening to a scientific presentation about protein
mimics as a diet pill for the control of mosquito larvae," Roe said.
He realized that the compounds being discussed were similar to a
compound found in wild tomatoes that Roe and another NC State
entomologist, Dr. George Kennedy, also a William Neal Reynolds
Distinguished Professor, had studied a number of years earlier.
Roe and Kennedy had studied the compound, which apparently is
part of the tomato's natural defenses against insects, to see if it
might be used to control worms that eat tomatoes.
Roe revisited the compound and tested it as a mosquito repellent.
He found that it not only repelled mosquitoes, but ticks as well.
Bennett said subsequent testing has shown that the substance also
repels fleas, cockroaches, ants and biting flies, as well as insects
that are agricultural pests such as aphids and thrips.
Roe said the compound is already used to make cosmetics, so its
toxicity has already been studied.
"What this means is that the toxicology has been done, which is a
big step toward commercialization," Roe said. "It's found in
tomatoes, it's natural, it can be obtained organically, it's safe
and it's at least as effective as DEET, all features that the public
would want for a new-generation insect repellent."
Roe added, "With the concern about West Nile virus and Lyme
disease - spread by mosquitoes and ticks, respectively - in the U.S.
and with the threat of other diseases like malaria outside the
United States, people need the personal protection of insect
repellents. And what about the nuisance factor of mosquitoes, ticks
and flies?"
Bennett added that the cost of producing IBI-246 is expected to
be competitive to the production cost of DEET.
Bennett said Insect Biotechnology has applied to the EPA for
approval to use IBI-246 as an insect repellent in several products.
While it is impossible to tell how long the approval process will
take, Bennett said he is hopeful IBI-246 will win EPA approval by
the end of the year.
This story has been adapted from a news release issued by
North Carolina State University.
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