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Researcher develops non-toxic method to wipe out cockroaches

By Susan Trulove

Spectrum Volume 17 Issue 20 - February 16, 1995

Half a billion dollars spent on insecticide to kill cockroaches is strong evidence that millions of people find the disease-carrying insect disgusting. But there is good news. A Virginia Tech researcher has developed a compound that not only wipes out cockroach populations and prevents re-infestation, but does it without the use of toxic chemicals.

Heather Wren, a research scientist in the university's entomology department, has discovered a combination of environmentally friendly, natural substances that prevents cockroaches from reproducing. Male cockroaches use up their life force as they breed, and the females' own bodies sabotage themselves as their eggs develop, so that the females die and the eggs are never laid.

The insects eat the bait because it contains a nutrient they require. "In our tests, they prefer this compound over their regular diets," says Wren. In addition to the nutritional attractant, the mixture contains an inhibitor that interferes with the way the cockroach is able to metabolize certain nutrients.

While it kills cockroaches, the bait will also prevent re-infestation because any migrant cockroaches will not be able to reproduce.

The discovery is a breakthrough in "insect-growth-regulator" technology. Previous growth regulators were based on killing nymph cockroaches at the molt stage. The new approach is based on the insect's nutrition metabolism, and is the only compound to kill adults.

It also prevents cockroaches from developing resistance. "What is happening now with regular spraying schedules, at restaurants for example, is that a few resistant cockroaches survive and reproduce. The offspring inherit resistance to a particular insecticide breed and thus increase the number that are resistant, until the entire colony is invulnerable to the insecticide," Wren explains. "With this bait in place, the resistant insects will not be able to breed."

The bait is non-toxic. Initial research was sponsored by the Virginia Pesticide Control Board, which encouraged the development of alternatives to toxic pesticides. Additional research to bring a product closer to commercialization was co-funded by Virginia's Center for Innovative Technology (CIT) and Dominion BioSciences Inc. The CIT promotes and coordinates science, technology, and economic-development initiatives in Virginia.

The bait is still in the development stage, with a U.S. patent pending on the invention. Dominion BioSciences, which has licensed the technology from Virginia Tech Intellectual Properties Inc., will apply for international patents in the near future. EPA-required testing will start in 1995. A commercial product is expected by 1997.

In the meantime, "to have a completely `green' product, Dominion BioSciences is looking to create a biodegradable bait station so that once the station has killed the cockroaches and been discarded, it will not remain forever in the landfill," says Steve Banegas, CEO and president of Dominion BioSciences.

"This new technology addresses common insect-pest problems that everyone wants to eradicate without the fear of harming the environment," says Banegas. "This leading-edge discovery by Dr. Wren is based on research using the `biorational' approach to design highly effective, safe pest-control alternatives for homeowners, lawncare professionals, and farmers."

While the compounds are being tested for release, Wren is investigating their use to control fire ants and mole crickets. "These insects are presently killed by spreading toxic chemicals on the ground--very bad for the birds that eat the dead insects and for ground-water quality," says Wren. "I want to try to correct that situation."

Wren also foresees adapting the product for termite control.

With pesticides being a $30-billion business worldwide, and the new mandates for clean and safe water, Dominion BioSciences was established in 1993 to help accelerate the development of safe pesticides.

"We source technologies from universities where there has been a wealth of resource investment--greater, probably, than in industry," says Joe Falkinham, professor of biology and Dominion's chief scientific advisor since its founding at the Virginia Tech Corporate Research Center. Falkinham adds that "the strategic role of Dominion is to work closely with university researchers such as Dr. Wren to transfer proprietary technology to commercial products that successfully address the needs of the agricultural and environmental industries."

Dominion's portfolio also includes a patented system developed at Virginia Tech to rapidly detect disease-causing viruses in drinking water.