GM research aims to predict crop impact

17 September 1999

GM research aims to predict crop impact

ALTHOUGH some genetically modified crops have been criticised for their knock-on effects on non-target organisms, new research shows that is not always the case.

Scientists at IACR-Rothamsted, led by Guy Poppy, are being funded by the UK government to develop laboratory models that can be used to predict the impact of releasing GM crops.

"We are developing a tiered risk-assessment protocol, similar to what conventional pesticides have to go through," says Dr Poppy. "It is important to judge these crops against the alternatives, in this case broad-spectrum insecticides which can affect the populations of beneficial insects."

Although there are no commercial or near-commercial insect-resistant crops in the UK at present, the latest report from the Rothamsted scientists focuses on Bt-modified oilseed rape.

Their experiments featured two strains of the diamond-back moth, one of which was resistant to the Bt toxin. In choice tests parasitic wasps preferred resistant caterpillars to susceptible ones when both were fed on Bt-leaves, mainly because the susceptible larvae quickly realised the leaves were toxic and stopped feeding.

But the resistant larvae kept on eating and the damaged leaves released more volatile scents, attracting more wasps to them. In addition, the report claims that wasps parasitising resistant moth larvae fed on Bt oilseed rape suffered no adverse effects on their behaviour as adults or on the survival of their larvae.

According to Dr Poppy, this shows the combination of GM plant and parasitoid wasp could be more effective than using conventional broad-spectrum insecticides. &#42

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