Oxitec applied for test GM insects

A UK biotechnology company Oxitec has applied for permission to carry out the first field trial in Europe of a genetically modified insect.

If it receives approval, the company will carry out a small-scale test of GM olive flies in Spain.

The aim is to combat this olive crop pest by releasing male flies that have a "female-killing gene".

If the GM flies can outbreed the wild flies, the female offspring will die - reducing the olive fly population.

The technology was invented by the co-founder and chief scientific officer of the biotech firm Oxitec, Dr Luke Alphey.

"Olive fly is the single major pest of olive production," Dr Alphey explained.

"In a bad year, you can lose of the whole of an olive crop.

"It's been treated with insecticides, but now there's a lot of resistance. So there it's a very hard pest to control."

According to Oxitec, the olive industry in Greece spends approximately €35 million (£30 million) annually on insecticides to control olive flies - to prevent an estimated loss to the industry of €650 million.

And thousands of miles from the European olive-growers, the company has already put its technology to use to combat the spread of a lethal disease.

Killer mosquitoes

In Brazil, Oxitec and its collaborators have progressed much further into their trial of genetically modified mosquitoes.

The basis of the technique is to inject the insect eggs with a lethal gene - a chunk of genetic code that programmes the flies to die as they're developing.

But rather than just kill all of the flies as they're reared, the scientists have tuned their modification so it specifically kills females.

And in the laboratory, the scientists rear their flies with a dietary supplement that acts as an antidote to the killer gene.

This means they can breed and rear generations of their GM flies to release into the wild.

But once they release the male GM flies, Dr Alphey explained, "those males will seek out the wild females, mate with those females and then their female offspring will inherit that gene and as they grow up, they will die."

In the most recent trial in a town called Mandacaru the company reported a 96% reduction in the dengue mosquito population.

"In fact all our trials have shown a 90% reduction or more," said Oxitec's chief executive Hadyn Parry.

The researchers are now applying the same technology to this olive-specific fruit fly.

"We have had years of lab experiments and cage experiments, and an experiment in a glasshouse in Crete," explained Dr Alphey.

"And the next step is the first transition to the field, which is what this Spain trial is."

If they receive permission from the Spanish authorities, the researchers will release GM flies around net-covered olive trees, to contain the insects and to prevent the experiment from "being swamped by flies in the environment".

Unpredictable environment

Helen Wallace from Genewatch, an organisation that monitors the use of genetic technology, has criticised the company for embarking on the trials.

"The fact that the female offspring are programmed to die at the larval stage, means there will be lots of GM maggots in these olives," she told BBC News.

Oxitec, however, has pointed out that for this netted trial, the crop will be destroyed.

Hadyn Parry, told BBC News: "Without trials no new technology of any sort can be developed".

He added that the technology would have to be approved by regulators in the EU and that "no regulator would approve a product that carries a health risk".