"Everyone is concerned," she said when asked the names of the top companies affected by France's decision, part of a wider plan to cut by 50 percent the use of phytosanitary products over the next 10 years.

Smaller companies were also implicated, but the spokeswoman did not yet have a complete list.

The move should come as no surprise to the firms involved as it was part of France's environmental strategy mapped out at the end of last year, she said.

France aims to gradually phase out the use of 53 phytosanitary substances in its fields. Licences for 30 of them will be scrapped this year, although a one-year delay was granted for three particular molecules, the time to find alternative products.

Germany's Bayer said the company would be little affected as it had already withdrawn a product containing tolyfluanide from the French market. It has products containing carbendazime but this substance was one of those which had been granted a delay, a company executive said.

"We are not really concerned by the measure, but the trend worries us because we think there will be a number of crop for which there will be no protection left," he said, adding that these would mainly include vegetables.

The other big companies affacted by the ban were not immediately available for comment.