CHICAGO (B)--An insecticide produced by genetically modified corn has been found to leach into the soil, according to research published in the recent issue of the science journal Nature.
The study is the first to show such an unintended impact on the environment from Bacillus thuringiensis (Bt) corn and is expected to add fuel to the growing controversy over the use of genetically modified organisms (GMOs).
Though some market watchers speculated that lingering toxin may have the side benefit of giving farmers additional pesticide control, Guenther Stotzky, the author of the study done at New York University, brushed that idea aside.
"It probably won't kill corn borers," Stotzky told Bridge News in an interview. "They don't eat soil, they eat plants. Our concern is for the non-target organisms. The toxin is in the plant to kill those insects eating the corn. Now the toxin is out into the environment and is no longer restricted to just the target insect."
The study found that the toxin
produced by Bt corn was present in and around the plant's roots as well as in the pollen and foliage above the ground. The longest period for which Stotsky ran the laboratory study was eight months, with the toxin still found in the soil at the end of that time.
Stotsky's research also found similar results in the field, although this information was not part of the Nature article.
"We know it's happening in the field," Stotsky said. "What was published in Nature was done in a plant-growth room, but we've also done it in the field and can detect the toxin even after the plants have died."
Stotsky said the research team found the toxin in the ground at different stages of growth, after the plant died and after the first frost.
This raises the issue of insects becoming resistant to the toxin.
"That's one of the potential hazards with the toxin present in the soil and persistent for so long," Stotsky said.
Seed companies that produce Bt corn have said one of its advantages is the reduced need for chemical pesticides. Environmentalists, on the other hand, have voiced concern that not only would the target insect--the European corn borer--become resistant to the hybrids, but that the Bt gene would find its way into other plants.
Previous research has found the toxin in the plant's pollen, killing Monarch butterfly caterpillars on neighboring milkweed plants. GMO pollen also has been said to cross-pollinate with non-GMO crops several miles away.
The initial reaction from grain market analysts was that this news would further inflame tensions over GMOs and that U.S. farmers would have one more reason to consider reducing their GMO acreage for 2000-2001, as has been widely forecast in recent weeks.