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Common Pesticides Threaten Bees, E.U. Watchdog Warns

Three pesticides routinely used by European farmers pose an "acute risk" to honey bees, according to the European Food Safety Authority (EFSA). In three studies published yesterday, EFSA addresses long-standing concerns of beekeepers and scientists about dwindling populations of pollinator bees, which are essential to farming and natural ecosystems.

The review, requested by the European Commission last year and carried out by EFSA's Panel on Plant Protection Products and their Residues, assesses the risks posed to bees by three types of neonicotinoid insecticides: clothianidin, imidacloprid, and thiamethoxam. This family of pesticides has been used by European farmers since the early 1990s and is sold by Syngenta in Basel, Switzerland, and Bayer CropScience in Monheim, Germany. EFSA says none of the three should be used on crops that are attractive to bees, such as maize, rapeseed, or sunflower. Although the study does not link the pesticides to the collapse of whole bee colonies, the agency's advice could open the door to a neonicotinoid ban in the European Union. Several countries, including France and Slovenia, have already restricted the compounds' use in the past years.

"With hindsight, EFSA appears to agree that the [initial approval procedure for neonicotinoids] was not thought through at the time," says ecologist David Goulson of the University of Stirling in the United Kingdom.

Syngenta has already pledged to defend its product, slamming EFSA's study as "hurried" and poorly researched. John Atkin, the company's chief operating officer, said in a statement issued yesterday that "this report is unworthy of EFSA and of its scientists." In a more gently worded statement, Bayer CropScience pointed out that "poor bee health and colony losses are caused by multiple factors," incriminating in particular the parasitic Varroa mite.

Antonio Gómez Pajuelo, biologist and owner of beekeeping consulting company Consultores Apícolas in Castellón, Spain, agrees that the toxicity of neonicotinoids is just one of many factors that affect bee health—including, for instance, parasites and climate change. But he says that Europe's approval procedures for insecticides are "too lax": In particular, they fail to assess the long-term effects of small, nonlethal doses on bee health.

The previous generation of widely used farming insecticides, the pyrethroids, were typically applied to the crops by spraying the field using a tractor; neonicotinoids are applied only to the seeds, a procedure called "seed dressing." At the time, this appeared to be a superior method, Goulson explains: Farmers save time and money by buying pretreated seeds, and the chemicals are applied to only the crop instead of to the whole field.

But neonicotinoids are systemic pesticides, meaning that they are present in the whole plant—including the nectar and pollen that bees feed on, or the droplets of sap exuded by maize seedlings. Besides, some toxic dust is created during sowing that can blow into the environment, and the chemicals can build up in the soil. EFSA's study examines these modes of contamination, which Goulson says were overlooked when neonicotinoids were first approved for sale.

Both Syngenta and Bayer seem to have prepared for a counterattack: They funded another study, released one day before EFSA's, by the Humboldt Forum for Food and Agriculture, a small think tank funded by Bayer CropScience and other businesses. It claims that banning neonicotinoids could cost 50,000 jobs and cause economic losses worth €17 billion over 5 years in the European Union.

Goulson dismisses this study as unsound "propaganda," pointing out that the industry is trying to protect a profitable market. Another study, published in 2009 by researchers at France's National Institute for Agricultural Research and the Helmholtz Centre for Environmental Research in Germany, put a €153 billion price tag on the annual economic value of pollination worldwide.

E.U. government officials will discuss neonicotinoids on 31 January, a commission spokesperson told reporters on Wednesday. He added that the commission was ready to "take the necessary measures" against the three chemicals if scientific evidence keeps piling up.