Sierra Club, US bee and honey groups urge EPA to ban clothianidin.

An insecticide used as a seed treatment on genetically modified corn and other crops has been found to be highly toxic to honey bees, according to a study published recently in the journal PLoS ONE.

The study may be a key to solving the mystery of Colony Collapse Disorder that has decimated bee populations over the last five years, causing losses of 30% and more of honey bee colonies every year since 2006, according to the US Department of Agriculture.

Found at levels 700,000 times a bee’s lethal dosage

Scientists at Purdue University documented major adverse impacts from the insecticide clothianidin (product name “Poncho”) on honey bee health. The study found that bees are exposed to clothianidin and other pesticides throughout the foraging period. Researchers found extremely high levels of clothianidin-as high as 700,000 times a bee’s lethal dosage-in seed planter exhaust material. It was found in foraging areas long after treated seed had been planted and in dead bees near hives in Indiana. It was also found in pollen collected by bees and stored in the hive. The study raises questions about the long-term survival of this major pollinator.

“This research should nail the coffin lid shut on clothianidin,” says Laurel Hopwood, Sierra Club’s chairwoman of the Genetic Engineering Action Team. “Despite numerous attempts by the beekeeping industry and conservation organizations to persuade the EPA to ban clothianidin, the EPA has failed to protect the food supply for the American people.”

“Clothianidin is among those most toxic to bees”

Clothianidin, which is manufactured by German agricultural company Bayer Crop Science, is of the neonicotinoid family of systemic pesticides. Clothianidin is taken up by a plant’s vascular system and expressed through pollen and nectar from which bees then forage and drink. Neonicotinoids are of particular concern because they have cumulative, sublethal effects on insect pollinators that correspond to Colony Collapse Disorder symptoms-namely, neurobehavioral and immune system disruptions.

According to James Frazier, Ph.D., professor of entomology at Penn State’s College of Agricultural Sciences, “Among the neonicotinoids, clothianidin is among those most toxic for honey bees; and this combined with its systemic movement in plants has produced a troubling mix of scientific results pointing to its potential risk for honey bees through current agricultural practices.”

Clothianidin has been widely used as a seed treatment on many of the country’s major crops, particularly GM corn, since 2003. Back then, the Environmental Protection Agency granted it a “conditional registration,” while EPA waited for Bayer to conduct a field study assessing the insecticide’s threat to bee colony health.