Neonicotinoid - Environmental Impacts

Environmental Impacts

In 2008, Germany revoked the registration of clothianidin for use on seed corn after an incident that resulted in the death of millions of nearby honey bees. Investigation of the incident revealed that it was caused by a combination of factors:

• failure to use a polymer seed coating known as a "sticker";
• weather conditions that resulted in late planting when nearby canola crops were in bloom;
• a particular type of air-driven equipment used to sow the seeds which apparently blew clothianidin-laden dust off the seeds and into the air as the seeds were ejected from the machine into the ground;
• dry and windy conditions at the time of planting that blew the dust into the nearby canola fields where honey bees were foraging;
• and a higher application rate which had been authorized for a severe root worm infestation. Clothianidin was also restricted for a short period for use on rapeseed; however, after evidence had shown that the problems resulting from maize seed were not transferable to rapeseed, its use was reinstated under the condition that the pesticide be fixed to the rapeseed grains by means of an additional sticker, so that abrasion dusts would not be released into the air.

In 2009, the German Federal Office of Consumer Protection and Food Safety decided to continue to suspend authorization for the use of clothianidin on corn. It had not yet been fully clarified to what extent and in what manner, bees come into contact with the active substances in the pesticides belonging to the neonicotinoid group (clothianidin, thiamethoxam and imidacloprid) when used on corn. In addition, on the basis of new findings, the question arose as to whether drops of liquid from plants, which are taken in by bees, pose an additional risk.

Neonicotinoid seed treatment uses are banned in Italy, but foliar uses are allowed. This action was taken based on preliminary monitoring studies showing that bee losses were correlated with the application of seeds treated with these compounds; Italy also based its decision on the known acute toxicity of these compounds to pollinators.

Sunflower and corn seed treatments of the active ingredient imidacloprid are suspended in France; other imidacloprid seed treatments, such as for sugar beets and cereals, are allowed, as are foliar uses.