Police have raided multinational chemical companies in France as part of an investigation into the unexplained sudden demise of thousands of bee colonies in the past three years.
Two French investigating judges are checking whether there is a connection between the destruction of the hives and the widespread use by farmers of an insecticide called Regent TS, marketed by the German chemicals giant BASF.
An independent scientific report commissioned by one of the judges concluded last week that the insecticide could be, in some circumstances, dangerous to bees and humans.
The judges are investigating alleged irregularities in the licensing of Regent TS by the French agriculture ministry. Senior officials of the ministry have also been questioned as part of the inquiry.
The French offices of BASF in the Paris suburbs and a subsidiary of the Bayer chemicals and pharmaceuticals company in Lyons have been raided. BASF denied yesterday that there was anything intrinsically dangerous about the use of Regent TS or its principal ingredient, fipronil.
The company said that the problems being investigated arose from one method of using the insecticide to treat seeds for agricultural use.
Beekeepers have been protesting for years against the use of so-called "systemic" insecticides on sunflowers and other plants. They say the insecticides are responsible for a much increased rate of deaths of entire colonies of bees.
Systemic insecticides are applied to seeds, or to seedlings, and are absorbed permanently into the plant. Concerns over the use of another insecticide called Gaucho led the French government to ban its use on sunflowers but to allow its continued use with maize.