Farmers are looking for more natural ways to fight insects, and research done by an Iowa State professor is shaping the future of natural pesticides.

According to a press release, methyl bromide, the second most widely applied insecticide in the world, will be phased out over the next three years because of ozone depletion.

Joel Coats, professor of entomology and toxicology, said methyl bromide in the stratosphere is degraded by sunlight to release bromine-free radicals. These radicals react with ozone very quickly, about 40 to 100 times more rapidly than chlorine radicals from the well-known CFCs in freon refrigerators.

“The Montreal Protocol was an international accord which set the production limits and phase out schedule for methyl bromide and other Class I ozone depleters by the year 2000,” Coats said.

Coats said the latest research on these natural products show them to be quite effective against nematodes and insects.

“We have been conducting research on natural insecticides for 12 years,” he said. “Most of the ones we worked on earlier were from essential oils of plants.”

Coats said for about five years, he worked with a class of compounds called glucosinolates, found in mustard, radishes and horseradish. His research was partially funded by the Center of Crop Utilization Research at ISU.

“When we started making synthetic versions of some glucosinolates, we made some other compounds that are naturally occurring, including specific ones that occur in flax, cassava, bamboo, almonds and other crops,” Coats said.

This particular project has been in progress for about three-and-a-half years, Coats said.

Coats discussed how he, along with Greg Tylka, associate professor of plant pathology, developed compounds specifically for fumigation of soybean cyst nematode but have found them to be very effective on insects as well.

“When Joel and I decided to collaborate, I checked out literature and found two published scientific papers describing the effect of some natural plant products on cyst nematodes, which I conduct research on,” Tylka said.

Tylka said cyst nematodes are microscopic worms that live in soil and feed off soybean roots, causing damage to the soybean plant.

“After that, Joel and I sought funding for our work, and when we received funding, I began testing compounds that Joel’s group had isolated and synthesized for activity against the soybean cyst nematode,” he said.

Tylka said the researchers assumed natural compounds would be less toxic to the environment because they already are being produced by natural organisms.

“We think these compounds inhibit the basic respiration of these nematodes and insects,” Coats said.

He said it is important that farmers have a natural defense against insects.

“In the future, there will be continuing need to develop and use ‘greener,’ more environmentally friendly insecticides in agriculture,” Coats said. “Biodegradability is one of the primary features required of such an insecticide.”

Coats said the researchers do not know when the technology will be available to farmers.

“If a company obtains a license through the ISU Research Foundation, then it may not be very long,” he said.

Coats added the patent is pending on the materials at this time.