Imidacloprid Effects On Bees - History

History

Imidacloprid was first registered in the United Kingdom in 1993 and in the United States and France in 1994. In the mid to late 1990s, French beekeepers reported a significant loss of bees, which they attributed to the use of imidacloprid. In 1999, the French Minister of Agriculture suspended the use of imidacloprid on sunflower seeds and appointed a team of expert scientists to examine the impact of imidacloprid on bees. In 2003, this panel, referred to as the Comité Scientifique et Technique (CST, or Scientific and Technical Committee) issued a 108-page report, which concluded that imidacloprid poses a significant risk to bees. In 2004, the French Minister of Agriculture suspended the use of imidacloprid as a seed treatment for maize (corn). Despite these bans, colony collapse disorder still is occurring.

Like most insecticides, imidacloprid is highly toxic to bees, with a contact acute LD50 = 0.078 ug a.i./bee and an acute oral LD50 = 0.0039 ug a.i./bee. Imidacloprid was first widely used in the United States in 1996 as it replaced 3 broad classes of insecticides. In 2006, U.S. commercial migratory beekeepers reported sharp declines in their honey bee colonies. This has happened in the past, however unlike previous losses, adult bees were abandoning their hives. Scientists named this phenomenon colony collapse disorder (CCD). Reports show that beekeepers in most states have been affected by CCD. Although no single factor has been identified as causing CCD, the United States Department of Agriculture (USDA) in their progress report on CCD stated that CCD may be "a syndrome caused by many different factors, working in combination or synergistically." In 2012, USDA researcher Jeff Pettis published the results of his study, which showed that bees treated with sub-lethal or low levels of imidacloprid had higher rates of infection with the pathogen Nosema than untreated bees. His research was confirmed by Alaux (2010) and Vidau (2011) who found that interactions between Nosema and neonicotinoids weakened bees and led to increased mortality.