Since unauthorised genetically modified wheat was found growing in a field in Oregon at the end of last month, the US Department of Agriculture has been investigating both the wheat's provenance and the extent of contamination, in a bid to sooth a backlash in the US wheat export market.  

On 29th May, USDA officials announced that a number of volunteer wheat plants, submitted for testing by a concerned farmer in April were revealed to be Monsanto's MON71800 wheat, a genetically engineered variety that had been trialled extensively over the previous decade, but abandoned in 2005 due to lack of demand. The grower sent the plants to a local lab for testing after discovering they were unaffected by glyphosate herbicide.

An official for the APHIS agency leading the investigation said last week that "USDA has neither found nor been informed of anything that would indicate that this incident amounts to more than a single isolated incident in a single field on a single farm." APHIS said it has overseen testing of seed sown in the field where the rogue GM wheat was found, wheat from the farmer's 2012 harvest, and is continuing investigations with the help of 200 growers from the area.

According to department spokesperson Ed Curlett, the USDA has conducted over 100 tests on wheat over the past month.  To date no further traces of the GM wheat have been found.

USDA has passed on the testing method for detecting MON71800, which was demanded by concerned trade partners (including the EU) when news of the contamination broke. Japan, Korea and Taiwan have all suspended US wheat imports since the GM wheat discovery was announced.   

Although the USDA maintains that there is no evidence to suggest the wheat has entered the supply chain, as the source of Oregon's GM contamination remains a mystery and harvest approaches, growers in the North-West are becoming increasingly concerned that their wheat will prove hard to shift.

Environment Secretary Owen Paterson yesterday reignited controversy over the future of GM crops in the UK with a speech delivered at Rothamsted Research, where the UK's only open air field trial of GM crops (a variety of GM Cadenza wheat) is being conducted. In the wake of his address, Paterson was accused of cynicism and manipulating WHO figures by insinuating "a causal link when there is none" between malnutrition in South East Asia and resistance to GM crops (specifically 'golden rice', a crop which has yet to be approved, and has been in development since 1999).

His speech at Rothamsted yesterday was blasted as patronising and supercilious by sustainable farming advocates and scientists; the Defra Secretary claimed to want to open up a debate on GM technology in Europe, while putting constraints on the scope of such debate and predicating that the outcome would be in his favour.