May 07 1999
CBC-R (Canadian National Radio)Genetically
Engineered Corn, Bugs and Pesticides
JUDY MADRIN (CBC-R): Scientists are discovering what could turn out to be
bad news for Canadian corn growers. Laboratory studies have found that bugs that eat
genetically altered corn may develop a tolerance for it. A significant
portion of Canada's corn is genetically altered to be resistant to pests. Anne
Stewart reports.
ANNE STEWART (Reporter): Corn can be genetically engineered so it contains a naturally
occurring pesticide known as BT toxin. Professor Randy Higgins is studying what happens to
bugs when they eat that toxin.
RANDY HIGGINS (Professor studying bugs and toxins): In our lab studies we
have fed some European corn bowers(?) toxin and some of those individuals are
able to survive a greater level of toxin in their food supply than
others.
STEWART: That means that some of the corn bowers are resistant to the toxin
in the plants. And that could be trouble for farmers who rely on the pesticide
to protect their crops.
HIGGINS: Whenever you find very useful means of pest control one of the
concerns is that if they're used very very widely, then what happens is you
can get into resistance.
STEWART: Professor Higgins says it's too soon to know whether the results he
found in the lab will also be found in the field. He's studying that now
but he does think Canada may need to consider alternative ways to handle insect
pests.
HIGGINS: We definitely should look at some sort of resistance management
plan to try to minimize the chance that we might have a problem later on in the
future.
STEWART: Critics of genetically modified foods find these results distressing. They're
worried that farmers will have very little choice but to use more chemical sprays.
Discovery for Corn Farmers
JUDY MADRIN (CBC-R): Scientists have made a discovery that won't be welcomed news for
corn farmers who depend on genetically modified plants to fight pests. So far the findings
only come from a lab and they haven't been tested in the field but they are creating some
concern. Ann Stewart reports.
ANN STEWART (Reporter): BT toxin is a natural pesticide made by bacteria living in the
soil. It kills certain kinds of insects, especially corn burrowers. They are bugs that
bore into the stocks of corn plants and feed on them. Organic farmers have been putting BT
on plants for years. But lately it's been put directly into plants using genetic
engineering. When corn burrowers eat the altered plants, they die. Studies done in a lab
in Kansas show that wide-spread use of BT could result in the corn burrowers developing
resistance.
Professor Randy Higgins explains.
RANDY HIGGINS (Professor who studies this issue): What would happen is you create a strain
of pest that you could not control through that means.
STEWART: Professor Higgins found that the resistance sometimes lasted for
several generations of corn burrowers. He's not sure whether the results of
the laboratory experiments will hold true for plants in the field. He's studying
that now but he says this could mean that BT toxin might be a useless pest
control.
HIGGINS: We definitely should look at some sort of resistance management
plan to try to minimize the chance that we might have a problem later on in the
future.
STEWART: That's just what some critics of genetically modified crops have
been predicting. Just how big a problem it could be for Canada's corn farmers
won't be clear until more studies are done. The critics say they wish those
studies had been done before the crops were put in the ground.
Ann Stewart, CBC news, Toronto. |
