The world's first genetically modified (GM) crop that has been deliberately engineered to emit a smell that repels insect pests is now growing in a small patch of land in the Hertfordshire countryside.
Scientists have created the GM "whiffy" wheat in an effort to combat aphid attacks that can cause upwards of £120m of damage each year to the UK's most important cereal crop, which has an annual value of £1.2bn – and rising.
The field trial, however, is also one of several "second generation" GM crops that scientists hope will be more acceptable to the British public who resoundingly rejected the first generation of commercial GM crops – such as herbicide-tolerant cereals – which are nevertheless grown extensively outside Europe.
The first commercial GM crop was developed in the early 1990s. It was a tomato that would remain fresh for longer after picking, and although consumed in the United States, it was never sold in the UK.
Monsanto, the multinational agrochemicals company based in St Louis, Missouri, then came up with a herbicide-tolerant soybean plant. The crop could grow even if sprayed with the herbicide glyphosate, which was conveniently made by the same company.
For many people, GM technology was not seen as a socially useful scientific development but a means for companies to increase their market share and profits. The death knell for GM in Britain probably came at the end of the 1990s when a scientist working at a UK research institute claimed to have shown that GM potatoes were poisonous to lab rats – even though the research methodology was widely condemned as flawed.
The green movement jumped on GM as anti-environment, while anti-capitalists claimed it was designed to maximise profits at the expense of the people. Meanwhile the Daily Mail came out against "Frankenfood" as unwarranted meddling with the food chain.
But now scientists believe the time has come to fight back. They believe time is running out for new ways to feed a growing human population, exacerbated by the growing number of wealthy people in the developing world who want to eat a protein-rich, meat-based diet. Scientists view GM as a way of extending the successful "green revolution" of the late 20th century into the 21st century.
This is the background to the GM wheat trial in Hertfordshire.
The GM wheat contains an added, synthetic gene that causes the plant to exude farnesene, an insect pheromone which is naturally produced by "frightened" aphids as a warning signal to other aphids. Although the chemical released by the GM wheat plants will be undetectable to the human nose, the scientists hope it will deter species of cereal aphids which spread harmful plant viruses as well as sucking energy from the crop.
An added advantage is that the aphid's fear pheromone has the opposite effect on beneficial insects, such as ladybirds and parasitic wasps that feed on aphids: they are attracted to the smell. The scientists hope these predators will visit the GM crop early enough in the growing season to prevent aphid infestations.
The small-scale field trial, at the government-funded Rothamsted Research station near Harpenden, is designed to test whether the GM wheat variety is able to repel significant numbers of aphids as well as attract the beneficial insects that feed on them.
Rothamsted's director, Professor Maurice Moloney, said: "GM has traditionally been associated with killing something. Either killing the weeds or killing the insects. In this case what we are doing is putting a 'no parking' sign on every leaf of the plant.
"It's a very different strategy from what's been done so far and I think it will open up many avenues that will allow us to use natural mechanisms and allow to respond to concerns from the public about the amount of pesticides that are used."
The field trial has been approved by the Government's Advisory Committee on Releases to the Environment, which has to oversee all outdoor GM experiments and field trials. Among the many preconditions was a stipulation that the GM wheat would not be eaten by humans or animals at the end of the experiment.
The committee also stipulated that the movement of pollen and seeds from the crop should be controlled with biological barriers and weed killer. A tall metal fence will keep out both humans and animals.
Professor John Pickett, the scientist in charge of the experiment, said there was still likely to be some opposition to the trial, even though it had been discussed in detail with people and organisations opposed to GM crops.
"We've had meetings with the public and anti-GM lobby groups, and we've found there is common ground because I think there is a lot of common interest in improving the sustainability of agriculture and in using natural processes," he said.
"We do feel there is a better view of GM technology from the public at large but we recognise there are some individuals who are strongly against this kind of thing and they may seek to disrupt it by direct action."
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