Professor homes in on natural pesticides
November 18, 1998
By Environmental News Network staff
(ENN) -- An Iowa State professor is working to lessen the agricultural impact on the ozone layer by developing environmentally friendly pesticides to replace methyl bromide.
Methyl bromide, the second most widely applied insecticide in the world, will be phased out over the next three years because of ozone depletion. Professor Joel Coats and some of his students and colleagues are working to help develop alternatives.
Coats, an entomologist and toxicologist, is studying two natural compounds from flax and cassava plants -- acetone cyanohydrin and methylethylketone cyanohydrin. Research shows the compounds kill several common and costly insect pests that feed on crops and stored grain in the United States. These insects include the maize weevil, the lesser grain borer, the red flower beetle, the drug store beetle and the saw-toothed grain beetle.
Coats and Greg Tylka, associate professor of plant pathology, have also found the natural pesticides destroy the eggs of the soybean cyst nematode, a costly pest that invades Midwest soybean fields.
Coats believes the natural compounds work as respiratory inhibitors in insects. The compounds are fumigants, vapor-borne insecticides of small, volatile molecules that can evaporate and penetrate to kill pests and their eggs. They are just as effective as the commercial insecticides but are biodegradable since they don't contain bromine or chlorine.
"Natural is the wave of the future," Coats said. "There will be a slow, sure change to natural insecticides."
Coats began looking for natural insecticides five years ago. Although the natural insecticides will probably be more costly than methyl bromide, they will be a viable alternative when methyl bromide is no longer legal, he said.
"The whole direction of insect control is going to have to go toward more specialized chemicals to use on specific pests as opposed to use of just a few broad-spectrum pesticides," Coats said.
The Iowa State University Research Foundation has a patent application pending for fumigants derived from natural resources based on Coats' work.
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