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    New evidence justifies ban on pesticide that endangers bees

    Ever since the global collapse of honeybee colonies began in 2006, environmentalists have speculated that pesticides were to blame. Now there is mounting evidence, and the United States should join with other nations in banning the farm use of chemicals linked to destruction of hives.

    The decline of honeybees is no ordinary ecological mystery; it’s a major threat to US agriculture. The bees have an economic value estimated by the federal government at between $15 billion and $20 billion, for pollinating the nation’s vegetables, fruits, nuts, and alfalfa, along with clover for livestock. Bees are involved in about a third of the human diet. Since the collapse began, beekeepers report, the percentage of bees that die off every winter has surged dramatically. While the nation still has 2.7 million colonies, the population has been dwindling every year.

    Many countries, including France, Germany, and Italy have banned or restricted the most worrisome class of neonicotinoid pesticides — including one called imidacloprid, which has been blamed by some scientists for damage to plant tissues and nectar, thereby making it a prime culprit in the deaths of bees. But in the United States, a cautious 2010 US Department of Agriculture report concluded that “no single factor” was responsible for the bees’ “malady.”


    Now, it seems, the Europeans were right, and the US approach was too cautious. Recently, researchers at the Harvard School of Public Health declared, in a study of bees in Worcester County, that 15 of 16 hives treated with imidacloprid were dead after 23 weeks. The pesticide appeared to paralyze the nervous systems of the bees. Bayer, the maker of imidacloprid, immediately attacked the research. It said the amounts of pesticide in the study were “spiked” well beyond “real world” levels.

    But lead researcher Alex Lu said the levels tested were actually below those commonly used on farms. He said imidacloprid at low levels had such a devastating effect on bees, it would be “prudent” to ban the pesticide. The Harvard study comes on the heels of two other bee studies in the journal Science. One found that honeybees that were fed sugar water laced with neonicotinoids were less likely to find their hives. The other found that bumblebees fed similar concoctions produced 85 percent fewer queen bees. The halls of the Environmental Protection Agency and the USDA should be buzzing with these findings about pesticides and the bees.