An internal EPA memo released Wednesday confirms that the very agency charged with protecting the environment is ignoring the warnings of its own scientists about clothianidin, a pesticide from which the German agrichemical giant, Bayer racked up about $262 million in sales in 2009.

Clothianidin has been widely used on corn, the largest U.S. crop, since 2003. Suppliers sell seeds pre-treated with it. Like other members of the neonicotinoid family of pesticides, clothianidin gets "taken up by a plant's vascular system and expressed through pollen and nectar," according to Pesticide Action Network of North America (PANNA), which leaked the document along with Beyond Pesticides. That effect makes it highly toxic to a crop's pests -- and also harmful to pollen-hoarding honeybees, which have experienced mysterious annual massive die-offs (known as "colony collapse disorder") here in the United States at least since 2006.

The colony-collapse phenomenon is complex and still not completely understood. While there appears to be no single cause for the annual die-offs, mounting evidence points to pesticides, and specifically neonicotinoids (derived from nicotine), as a key factor. And neonicotinoids are a relatively new factor in ecosystems frequented by honeybees -- introduced in the late 1990s, these systemic insecticides have gained a steadily rising share of the seed-treatment market. It does not seem unfair to observe that the health of the honeybee population has steadily declined over the same period.