Genetically modified corn helps nearby fields: study

CHICAGO (Reuters) - Corn that is genetically modified to resist pests benefits neighboring crops as well, U.S. researchers said Thursday.

They said Midwestern states that planted corn genetically modified to make a toxin that fights off European corn borer moths has dramatically cut the $1 billion in annual losses from the pest, even preserving crops that have not been altered.

“This study is the first to estimate the value of area-wide pest suppression from transgenic crops and the subsequent benefit to growers of non-transgenic crops,” said Paul Mitchell, a University of Wisconsin-Madison agricultural economist who worked on the study published in the journal Science.

While supporters see genetically modified crops, or GMOs (genetically modified organisms), as a way to meet increasing global food demands, GM foods can be deeply controversial.

Some detractors call them “Frankenfoods,” and many governments, including Japan, Kenya and the European Union, ban them entirely. The United States allows GMOs.

Commercial GM planting in Europe last year covered less than 100,000 hectares (247,100 acres), mostly in Spain, compared with 134 million hectares (331 million acres) globally.

Earlier cost-benefit studies have looked only at the effect on the genetically modified corn itself, but the study, led by William Hutchison of the University of Minnesota, shows the wider impact caused by crops modified to make their own insecticide -- the toxin made by soil bacterium Bacillus thuringiensis, or Bt.

According to the team’s calculations, Bt corn planted in Wisconsin, Minnesota, Illinois, Iowa and Nebraska over the past 14 years saved up to $6.9 billion, and 62 percent of that savings -- or about $4.3 billion -- came from fields that were not genetically modified.

Potato, green bean and other crops also stand to benefit, the researchers said.

“We’ve assumed for some time that economic benefits were accruing, even among producers who opted not to plant Bt hybrids,” Mike Gray of the University of Illinois, who worked on the study, said in a statement. “However, once quantified, the magnitude of this benefit was even more impressive.”

Corn borer moths, historically one of corn’s key pests, cannot tell the difference between Bt and non-Bt corn, so females lay eggs in both. Once eggs hatch in Bt corn, the larvae feed and die within 24 to 48 hours.

Bt corn, made by companies like Syngenta and Monsanto, became widely used in the United States in 1996. They now make up 63 percent of all U.S. corn acres, cutting corn borer populations in non-Bt fields by 28 to 73 percent in Minnesota, Illinois and Wisconsin, the researchers said.

For best protection, farmers should continue to plant both Bt and non-Bt crops, which will reduce the chances that the moths will develop resistance to the toxin, they said.

Editing by Maggie Fox and Eric Beech