Independent on Sunday (London)
March 30, 2003
INSECTS THRIVE ON GM 'PEST-KILLING' CROPS
BY GEOFFREY LEAN ENVIRONMENT EDITOR

Genetically modified crops specially engineered to kill pests in fact
nourish them, startling new research has revealed.

The research - which has taken even the most ardent opponents of GM
crops by surprise - radically undermines one of the key benefits
claimed for them. And it suggests that they may be an even greater
threat to organic farming than has been envisaged. It strikes at the
heart of one of the main lines of current genetic engineering in
agricultu breeding crops that come equipped with their own
pesticide.

Biotech companies have added genes from a naturally occurring poison,
Bacillus thuringiensis (Bt), which is widely used as a pesticide by
organic farmers. The engineered crops have spread fast. The amount of
land planted with them worldwide grew more than 25-fold - from four
million acres in 1996 to well over 100 million acres (44.2m hectares)
in 2000 - and the global market is expected to be worth $ 25bn (pounds
16bn) by 2010.

Drawbacks have already emerged, with pests becoming resistant to the
toxin. Environmentalists say that resistance develops all the faster
because the insects are constantly exposed to it in the plants, rather
than being subject to occasional spraying.

But the new research - by scientists at Imperial College London and
the Universidad Simon Rodrigues in Caracas, Venezuela - adds an
alarming new twist, suggesting that pests can actually use the poison
as a food and that the crops, rather than automatically controlling
them, can actually help them to thrive.

They fed resistant larvae of the diamondback moth - an increasingly
troublesome pest in the southern US and in the tropics - on normal
cabbage leaves and ones that had been treated with a Bt toxin. The
larvae eating the treated leaves grew much faster and bigger - with a
56 per cent higher growth rate.

They found that the larvae "are able to digest and utilise" the toxin
and may be using it as a "supplementary food", adding that the
presence of the poison "could have modified the nutritional balance in
plants" for them.

And they conclude: "Bt transgenic crops could therefore have
unanticipated nutritionally favourable effects, increasing the fitness
of resistant populations."

Pete Riley, food campaigner for Friends of the Earth, said last night:
"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.

"It destroys the industry's entire case that insect-resistant GM crops
can have anything to do with sustainable farming."

Patrick Holden, director of the Soil Association, said it showed that
GM crops posed an even "worse threat to organic farming than had
previously been imagined". Breeding resistance to the Bt insecticide
sometimes used by organic farmers was bad enough, but problems would
become even greater if pests treated it as "a high-protein diet".