Bee poisoning caused by insecticidal seed treatment of maize in Germany in 2008

Abstract

Background: In late April and early May 2008 a bee mortality occurred in parts of South-West Germany, which affected approximately 12,000 colonies of bees, some of them substantially. Immediately after this became known, an intensive search for the causes of these incidences was started. Results: Very soon, maize seeds which had been treated with the insecticidal substance clothianidin were suspected as a possible cause. Only two weeks later a clothianidin poisoning was confirmed by the JKI. On May 15, 2008 the BVL-authority ordered suspension of the authorisation of a number of insecticidal seed treatment products, especially those containing neonicotinoid substances such as clothianidin, imidacloprid and thiamethoxam and in addition methiocarb. Conclusions: For all future authorizations of pesticides used as seed treatments additional conditions for use will be applied for precautionary reasons. These will cover: the use of additional stickers, maximum permissible values for abrasion, where applicable, the prohibition of sowing of treated seeds at wind speed higher than 5 m/s, the obligation to incorporate treated seeds including dusts into or directly onto the soil, the ban of vacuum systems, unless the exhaust air pipe allows for an incorporation of dusts into the soil or directly onto the soil, where applicable.