By Carey Gillam
Aug 28 Researchers in the key corn-growing state
of Illinois are finding significant damage from rootworms in
farm fields planted in a rotation with a genetically modified
corn, a combination of measures that are supposed to protect the
crop from the pests, according to a new report.
"It's very alarming," said Joe Spencer, an insect
behaviorist with the Illinois Natural History Survey who is
researching the issue.
Evidence gathered from fields in two Illinois counties
suggests that pest problems are mounting as the rootworms grow
ever more resistant to efforts to fight them, including crop
rotation combined with use of the biotech corn, according to the
report issued by Michael Gray, a professor of crop sciences at
the University of Illinois, in conjunction with Spencer.
Farmers across "a wide swath of Illinois" could face
formidable challenges protecting corn crops from the hungry
insects, Gray said in the Aug. 27 report.
The crop damage was found in fields where the specialized
biotech corn had been planted in a rotation following soybeans,
a practice that typically helps beat back the rootworm problems
as western corn rootworm adults typically lay eggs in cornfields
and not in soybean fields.
But a large number of adult western corn rootworms were
collected in both the damaged corn fields and from adjacent
soybean fields. And they appear to also be resistant to the
biotech corn, a double whammy for farmers.
"It looked like continuous corn and use of the same trait
year after year is what produced resistant beetles," said
Spencer. "Growers thought their get-out-of-jail-free card was
just to rotate to soybeans. But what we're seeing in northeast
and east-central Illinois is beetles that are also resistant to
Western corn rootworm is one of the most devastating corn
rootworm species in North America, especially in the Midwestern
corn-growing areas. The rootworm larva feed on the roots of corn
plants, reducing a plant's ability to grow normally, and can
dramatically cut production.
Monsanto Co introduced genetically modified corn
designed to protect from the rootworms in 2003. The corn, which
contains a protein referred to as "Cry3Bb1," has been popular
with farmers in key growing areas around the country, and is
supposed to reduce the need to put insecticides into the soil.
But last year, a group of academic corn experts warned the
Environmental Protection Agency they were worried about
long-term corn production prospects because of growing
resistance of the rootworm to the genetic modifications in corn.
Monsanto spokesman Jeffrey Neu acknowledged "pockets of
heavy corn rootworm pressure in isolated areas of Illinois," and
said the company was working with farmers to address the
problems. Crop rotation is key, as well as using different corn
seed products, he added.
Rodney Williamson, director of research and development with
the Iowa Corn Growers Association, said there have been reports
of resistance problems in Iowa, but not to the level of concern
seen in Illinois.
He stresses that farmers do not want to stop using the
biotech corn because it helps reduce pesticide use, and added
that there was an effort underway to pursue various field and
crop management practices to try to mitigate crop losses tied to
"People are taking efforts to address it," he said.
"Rotating modes of action, that will be one of the best things
we can do."