A controversial trial of genetically modified (GM) wheat has failed to repel pests any more effectively than ordinary crops, scientists have found.

Researchers attempted to engineer a variety of wheat to emit an odor that deters aphids in the hope of reducing the amount of pesticides required by plants.

The crops, nicknamed “whiffy wheat,” were successful in lab tests, but succumbed to aphids when trialed in the field.

The experiment cost £3m, some £2.2m of which was spent on fencing and other security measures to protect the trial from animals and saboteurs.

Campaign group GM Freeze said the experiment was a waste of money and further evidence of the “folly” of investing in GM technology.

Agricultural institution Rothamsted Research ran the trial in Hertfordshire from 2012 to 2013.

Scientists had hoped to create a strain of wheat capable of deterring aphids – such as greenfly and blackfly – from eating the crops and spreading infections.

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They changed the structure of the plants to produce a natural pheromone – commonly found in peppermint – which aphids release when attacked by predators.

Researchers hoped the modified plants would no longer need to be sprayed with insecticides.

While lab tests found the pheromone worked as a highly effective repellent, field tests revealed there was no difference between modified crops and conventional plants.

Senior molecular biologist Professor Hew Jones, who worked on the trial, said: “As scientists we are trained to treat our experimental data objectively and dispassionately, but I was definitely disappointed.

“We had hoped that this technique would offer a way to reduce the use of insecticides in pest control in arable farming. As so often happens, this experiment shows that the real world environment is much more complicated than the laboratory.”

GM Freeze said the experiment was a waste of public money.

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Its director Liz O’Neill said: “The waste of over £1m of public funding on a trial confirms the simple fact that when GM tries to outwit nature, nature adapts in response.”

Speaking to the BBC, author and campaigner Tony Juniper raised concerns about the wider implications of GM crops.

The former Executive Director of Friends of the Earth said there is still concern about the impact of GM crop ownership, via patents, on the global food system.

Juniper said: “I still believe the industry is finding it hard to prove a role for itself and that conversations going on around more integrated approaches to farming - that rely less on technological ‘silver bullets’ – have more potential than the pursuit of GM methods, that often miss the point as to what the actual problem is.

“Then there are the issues about who controls the technology, via patents, contracts and royalty payments, and how the widespread uptake of GM farming could have profound impacts in terms of how power is distributed across the food system.”