Biotech Corn and Butterflies
kancell at goodearthgardens.com
Mon Sep 10 17:43:08 EDT 2001
Biotech Corn Poses Negligible Risk to Butterflies, Studies Say
Monday, September 10, 2001
AP Wire: WASHINGTON - Studies of corn that is genetically engineered to
produce its own insect killer found that the crop is having virtually no
impact on monarch butterflies that live in farm fields.
The scientists say that the real danger to the butterflies may be the
spraying of weed killers and insecticides, not the growing of the
The studies, which are being published online this week by the Proceedings
of the National Academy of Sciences, will likely clear the way for the
Environmental Protection Agency to renew registrations for the two most-used
varieties of the corn.
EPA, which has already reviewed data from the studies, announced this summer
that it did not think the corn posed a significant risk to monarchs.
Monarch larvae feed on the leaves of milkweed plants, which are often found
in Midwest corn fields. But the scientists estimated, based on field
studies, that at most 500 in a million caterpillars' larvae would die from
eating corn pollen that is deposited on the milkweed.
"By and large, at least with the current, dominant varieties on the market,
it doesn't look like you're ever going to get a pollen density in the field
that would reach the threshold where you would have some kind of detrimental
effect," said one of the scientists, Iowa State University entomologist John
The scientists said that earlier laboratory studies that suggested the
pollen could be toxic to butterflies may have been flawed because ground-up
parts of the corn plant were mixed in with the pollen.
The biotech corn, known as Bt corn for a bacterium gene that makes it toxic
to the European corn borer, grabbed worldwide attention in 1999 after
release of a lab study at Cornell University. That finding produced a public
outcry in Europe and calls from environmental groups to curb the spread of
genetically engineered crops.
Bt varieties account for nearly 20 percent of this year's corn crop.
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