Environmentalists might one day run barefooted through
insect-rich fields of genetically modified crops. At least, they might
if the conclusions of a two-decade study in China hold up.
Kongming Wu of the Chinese Academy of
Agricultural Sciences in Beijing and colleagues looked at the impact on
surrounding farms of Bt cotton, a GM crop that protects itself against
bollworm larvae by making its own pesticide.
As pesticide sprays were no longer
needed, beneficial predator insects such as ladybirds, spiders and
lacewings could thrive and spill over onto neighbouring farms, where
they ate aphids. This reduced the amount of pesticides neighbouring
farmers used.
"Transgenic Bt crops with less
insecticide use can promote population increases of predators in the
whole agricultural landscape," says Wu.
Protesters in the UK recently
threatened to disrupt a trial at Rothamsted Research in Harpenden of a
GM wheat that gives off a scent repelling aphids. Rothamsted's John Pickett
said the Chinese research is exciting because it shows that certain GM
crops can spread beneficial insects to neighbouring farms.
Dispelling myths
"This is another chapter of research
dispelling the myth that GM crops are environmentally damaging," says
Julian Little, chairman of the UK's Agricultural Biotechnology Council, which backs GM crops.
In 2010, Paul Mitchell
of the University of Wisconsin-Madison found that US growers of
conventional maize benefitted economically from having an adjacent Bt
maize farm, because it suppressed maize-damaging pests. "This paper is
part of the ongoing research documenting the environmental, economic and
social benefits that Bt crops generate for more than just their users,"
he says.
But the Soil Association, which
represents organic farmers in the UK, says earlier data from the same Bt
cotton study shows that new insect pests may emerge, forcing farmers to
increase crop spraying (Science, DOI: 10.1126/science.1187881).
Journal reference: Nature, DOI: 10.1038/nature11153
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