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2-Plants: Many U.S. farmers ignore Bt crop refuge obligations

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TITLE:  Pest resistance feared as farmers flout rules 
        Small refuge areas found in midwest transgenic maize crops.
SOURCE: Nature, UK, by Tom Clarke
DATE:   Jul 10, 2003

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Pest resistance feared as farmers flout rules 
Small refuge areas found in midwest transgenic maize crops.

Nearly one-fifth of farmers in the US midwest are ignoring federal rules
about how much transgenic maize (corn) they can plant, according to
government figures. Experts fear that this non-compliance could encourage
insects to develop resistance to the insecticide produced by the crop.

Some transgenic maize contains a gene from the bacterium Bacillus
thuringiensis (Bt), which allows the corn to produce a natural
insecticide. Under rules laid down by the Environmental Protection
Agency, farmers who plant Bt maize must devote 20% of their acreage to
non-Bt varieties. These 'refuge' areas should prevent pests from
developing resistance to the insecticide, as resistant insects will breed
with susceptible insects living in the refuge and dilute the trait.

But a study released last month by the Center for Science in the Public
Interest (CSPI), a Washington-based pressure group, reveals that this
rule is being ignored. The report describes data from the US Department
of Agriculture showing that last year 19% of all Bt maize-growing farms
in Iowa, Minnesota and Nebraska failed to plant the necessary refuges. No
refuge at all was planted on 13% of the farms.

Most farms that broke the rule were small, planting less than 80 hectares
(200 acres) of Bt maize. Farms of this size are not monitored by the
Agricultural Biotechnology Stewardship Technical Committee, the industry
body that monitors growing practices.

"It's just a matter of time before resistance develops," warns the
report's author Gregory Jaffe, director of biotechnology projects at the
CSPI. Bt maize will be rendered useless, adds Jaffe, if pests such as the
European corn borer, the chief target of transgenic maize, develop resistance.

But transgenic-crop firms disagree. "This won't jeopardize the long-term
effectiveness of the technology," says Eric Sachs, director of scientific
affairs at biotechnology company Monsanto, based in St Louis, Missouri.
Those ignoring the rules grow just 5% of Bt maize planted in the three
states, he says.

This won't jeopardize the long-term effectiveness of the technology Eric
Sachs Monsanto

Only 25% of maize grown in the midwest contains Bt, and the likelihood
that non-compliance from a fraction of these farms will lead to
resistance is small, agrees insect ecologist Bruce Tabashnik at the
University of Arizona in Tucson. "It's unlikely that there is sufficient
pressure on the insects," he says. In seven years of academic field
surveys, insects resistant to Bt maize have not been documented in the
United States, Tabashnik adds.

But this could change. New Bt maize, developed by Monsanto and designed
to control a root pest, the maize rootworm, is due to be sown next year,
and is expected to be adopted far more widely than existing Bt varieties.
"Although non-compliance may not be an immediate hazard, it could lead to
a serious problem in the future," says Tabashnik.

The transgenic-crop developers maintain that small farms won't pose a
major problem - but they are concerned. "It's not clear that we have a
problem of biological significance," says Val Giddings, vice-president
for food and agriculture with the US Biotechnology Industry Organization,
"but we do have a problem of regulatory significance."


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