- 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 agriculture: 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 ,Äì
from four million acres in 1996 to well over 100 million acres (44.2m hectares)
in 2000 ,Äì and the global market is expected to be worth $25bn
(¬£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 ,Äì by scientists at
Imperial College London and the Universidad Simon Rodrigues in Caracas,
Venezuela ,Äì 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 ,Äì
an increasingly troublesome pest in the southern US and in the tropics
,Äì 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 ,Äì 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".