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Genetically engineered
crops designed to be resistant to weed killers are sprouting
so-called superweeds that cannot be killed with traditional
herbicides.
The soybean, cotton
and corn crops, sold under the brand name Roundup Ready, are
the world’s largest group of genetically altered crops.
In fact, the altered soybeans now make up more than three-quarters
of all soybeans grown in the United States. The Roundup Ready
gene is also part of 65 percent of the cotton and 10 percent
of the corn grown in the United States.
While farmers like
the modified crops because Roundup herbicide can be sprayed
directly onto the fields, killing weeds without harming crops,
the widespread popularity of the crops is rendering the herbicide
ineffective against some weeds.
Crop scientists
say that the crops’ prevalence has greatly increased
the use of Roundup herbicide. As a result, the rare weeds
that survive the herbicide will ultimately flourish in the
"survival of the fittest" environment. Herbicide-resistant
weeds have already popped up in Delaware, Maryland, California,
Tennessee, Ohio and Indiana.
While currently
the few types of resistant weeds can be killed with other
herbicides, some scientists are concerned that the resistance
may spread, leaving Roundup less effective. As glyphosate,
the generic name for Roundup, is the most-used weed-killer
in the world, the fate of the chemical’s usefulness will
greatly impact farmers.
Experts say that
in order to maintain the long-term usefulness of the crops,
the use continuous use of Roundup and Roundup Ready crops
will need to be reduced.
However, Roundup
has gained so much popularity that other chemical companies
have reduced investments in developing new herbicides. The
lack of new herbicides on the market may make it hard to find
a suitable replacement for Roundup.
Monsanto, the company
that developed both Roundup and the Roundup Ready crops, reported
that the herbicide-resistant weeds are not a significant problem,
and expect the use of both products to continue increasing.
Roundup brought in 40 percent of the company’s 2002 revenue,
estimated at a total of $4.6 billion, while Roundup Ready
crops had revenue of about $470 million in 2002.
Since Roundup Ready
crops were introduced in 1996, the use of glyphosate has increased
two and a half times, with even higher increases in the Midwest.
According to scientists
resistance develops with most all herbicides, and the fact
that Roundup has not developed a significant resistance yet
suggests that resistance will not be spread quickly. However,
although Roundup has been used for close to 30 years, resistance
has only recently become an issue.
Scientists recommend
using a variety of herbicides in order to prevent resistance.
However, crop specialists say that unless resistance becomes
severe, farmers are not likely to reduce their use of Roundup
and Roundup Ready crops.
The
New York Times January 14, 2003
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