There is growing evidence that a pesticide made by Bayer is causing bee colony collapse ["colony collapse disorder" (CCD)].
Neonicotinoids: A relatively new class of systemic insecticides (neonicotinoids) covers at least 142 million acres of countryside, much of it corn – on which bees rely heavily for protein. As systemics, these insecticides are water soluable, coursing through plants’ vascular systems to be expressed in pollen, nectar and guttation droplets. This class also happens to be very long-lasting, so they are accumulating in the soil and showing up in the nectar of non-treated plants like dandelions. The most widely used of these neonicotinoids (imidacloprid, clothianidin, thiamethoxam) are known to be highly acutely toxic to bees, and have a variety of sub-lethal effects ranging from disorientation to memory, immunity and reproductive impairment. These pesticides are clearly harming bees – but so do a lot of other pesticides. What makes these neonicotinoids suspect is that they are known to be highly toxic to bees, pervasive, long-lasting and relatively new. Perhaps coincidentally, the emergence of CCD in the U.S. roughly coincides with the 5-fold increase in neonics as seed treatments.