One of the main reasons to genetically engineer crops was to
develop plants that are resistant to insects, by having
pesticide engineered into the plants themselves. But new
research shows that insects love GM crops! The first problem
is that pests become resistant to the pesticide, meaning they
won't be killed when the same pesticide is sprayed on non-GM
plants. Scientists say that the insects' resistance develops
more quickly than ever because they are constantly exposed
to the toxin, rather than just trying to survive an occasional
spraying. But now researchers have discovered that insects
actually use the poison as a food, so that rather than
controlling pests, the GM crops actually help them thrive.
Scientists fed pesticide-resistant larvae of the diamondback
moth, a troublesome pest on southern U.S. farms, on normal
cabbage leaves, as well as leaves that had been treated with
Bt toxin. The larvae eating the treated leaves grew much
faster and bigger, with a 56% higher growth rate. They found
the larvae "are able to digest and utilize" the toxin and may
be using it as a "supplementary food," say the researchers.
Pete Riley, of Friends of the Earth, says, "This is just another
example of the unexpected harmful effects of GM crops. If
Friends of the Earth had come up with the suggestion that
crops engineered to kill pests could make them bigger and
healthier instead, we would have been laughed out of court."
GM Foods is one of the many important topics covered by
science reporter
Linda Howe on
Dreamland every week.
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