http://www.salon.com/news/environment/feature/2009/05/18/bees_pesticidesBeekeepers have singled out imidacloprid and its chemical cousin clothianidin, also produced by Bayer CropScience, as a cause of bee die-offs around the world for over a decade. More recently, the same products have been blamed by American beekeepers, who claim the product is a cause of colony collapse disorder, which has cost many commercial U.S. beekeepers at least a third of their bees since 2006, and threatens the reliability of the world's food supply.
Scientists have started to turn their attention to both products, which are receiving new scrutiny in the U.S., due to a disclosure in December 2007 by Bayer CropScience itself. Bayer scientists found imidacloprid in the nectar and pollen of flowering trees and shrubs at concentrations high enough to kill a honeybee in minutes. The disclosure recently set in motion product reviews by the California Department of Pesticide Regulation and the EPA. The tests are scheduled to wrap up in 2014, though environmentalists, including the Sierra Club, are petitioning the EPA to speed up the work.
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Imidacloprid was approved with knowledge that the product, marketed as Gaucho, Confidor, Admire and others, was lethal to honeybees under certain circumstances. Today the EPA's own literature calls it "very highly toxic" to honeybees and other beneficial insects. Its workaround was to slap a label on the product, warning farmers not to spray it on a plant when bees were foraging in the neighborhood.