A GENETICALLY modified grass designed to improve golf courses and lawns has caused alarm in the US after escaping into the wild.

Creeping bentgrass, Agrostis stolonifera, has spread up to three miles outside a test site in Oregon with nine different plants being identified.

It had been modified to make it impervious to the herbicide glysophate and was designed to appeal to golf course managers who would be able to spray large areas to kill off weeds without damaging the grass.

Homeowners were considered another lucrative market because it could help them to create perfect lawns in front of their houses.

The US Department of Agriculture has ordered a full environmental audit of its impact and spread to determine the threat to wildlife. Unlike GM crops such as maize and soybeans, which are annuals and unable to reproduce, the perennial grass was able to produce seeds during outdoor tests.

Some of the plants found outside the test site, reports New Scientist, had grown from seeds produced by the GM parent. Others were hybrids derived from a non-GM plant being pollinated by one of the modified specimens.

Jay Reichman, of the US Environmental Protection Agency, which identifed the escaped grasses, said: “It’s a cautionary tale of what could happen with other GM plants that could be of greater concern.”

GM bentgrass has yet to be given official approval by the USDA for commercial use but environmentalists are concerned that widespread take-up will quickly see it spread into ecologically sensitive wilderness areas.

A spokeswoman for the USDA said: “This is a perennial and has wild and weedy relatives and it’s something we think we need to know the environmental impact of before it’s deregulated.” She added: “Some of the seeds were dispersed and some of the pollen. We are following up on this to make sure all the plants outside the test area are dug up and recovered.

“We have a lot of measures in place to try to prevent this type of thing. However, there is human error that can occur.”

Eric Baack, of Indiana University, told the journal Current Biology: “It’s definitely a new set of variables we’ve not had to deal with in previous GM crops.” He doubted, however, that the escape would cause alarm beyond scientific and environmental circles: “I don’t think people will worry about lawns and golf courses if they have not shown any worries already about GM food.”

It is uncertain how much the genetic modification would help the plant in the wild where the herbicide would not be expected to be used.

The modification is not believed to have conferred any other advantage on the grass and it is possible that it has evolutionary weaknesses that are not shared by non-GM plants.

Among the factors that the USDA will take into account while carrying out an environmental assessment are the level of resistance to herbicide, the ability to hybridise and the damage to the environment.

In deciding whether the grass should be deregulated for the commercial market, officials will consider how widespread the grass could become.

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