French farmers destroyed a total of 18,000ha of rapeseed, more than double the area initially expected, following the discovery of a non-authorised genetically modified organism (GMO) in seeds, German group Bayer said.

Bayer announced in February that farmers in France and Germany were turning over thousands of hectares of rapeseed crops after traces of a GMO variety grown in Canada were detected in batches of seed sold in Europe.

GMO crops are widely grown across the world, but remain controversial in Europe, where very few varieties are authorised for growing and countries like France have completely outlawed their cultivation, citing environmental risks.

A spokesperson for Bayer, which had previously estimated around 8,000ha of rapeseed would be lost in France, said on Friday the area had reached 18,000ha after further precautionary removals of crops, for example when there were doubts over the traceability of seeds.