By Patricia Reaney
LONDON (Reuters) - U.S. scientists said Wednesday they had uncovered what  could be either a potential hazard or benefit of genetically modified (GM)  corn.  Dr Guenther Stotzky and researchers at New York University have shown that BT corn -- the seed variety which is resistant to corn borer pests -- releases an insecticide through its roots into the soil.
The toxin remains in the soil because it is not easily broken down. It retains its insecticide properties, which could help to control pests or promote insects resistant to the pesticide -- the scientists aren't sure which.
"Further investigations will be necessary to shed light on what might happen underground," Stotzky and his colleagues said in a report in the science journal Nature. Their work is the first to show that the toxin from the genetically-engineered BT corn can seep into the soil.  Stotzky said so far there was little evidence that GM technology was potentially harmful but the discovery would add to the confusion about the safety of GM crops.
About 15 million acres of BT corn were planted in the United States in 1998, which represents about 20 percent of the total acreage of corn.  "There is a potential hazard that it (the toxin) builds up and could enhance the selection of resistant target organisms and could possibly 
effect non-target organisms," Stotzky said in a telephone interview.  "Theoretically it could affect any organism that is susceptible to the toxin."
The BT corn contains the genes that allow it to produce the insecticide. The amount of it in the plant is minimal so the hazard to people eating it is essentially non-existent, he said.
But Stotzky called for more studies to determine the impact of the toxin's build-up in the soil on insects and other organisms.  "Those studies need to be done. They should have been done a long time ago before the regulatory agencies allowed the release of these plants," he 
added.