Fipronil responsible for historic honeybee die-off

A nearly three-decade-old mystery of mass honeybee mortality appears to have been solved by researchers in the UK. The collapse of bee colonies in France during the mid- to late-1990s was widely blamed on the neonicotinoid insecticide imidacloprid, but new research has revealed the likely culprit to be the much less high-profile fipronil. Imidacloprid hit the market in 1994 and fipronil was released in 1993, with both products being widely used on French sunflower crops.