Another Study Links Bee Population Decline to Neonicotinoid Pesticides

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Photo by Fotolia/Dani Vincek
Biologists have found more than 150 different chemical residues in bee pollen. This toxin overload of neonicotinoids and other pesticides contributes to bee population decline.

A new study from Harvard University has concluded that systemic neonicotinoid pesticides contribute to honeybee colony collapse disorder (CCD), which has claimed billions of bees since it was first identified in 2006. In the study, all of the previously healthy colonies of bees exposed to imidacloprid or clothianidin — types of neonicotinoid pesticides — from July to September 2013 either died or exhibited CCD symptoms during the winter months. (Read the full study at the Bulletin of Insectology.)

“We demonstrated again in this study that neonicotinoids are highly likely to be responsible for triggering CCD in honeybee hives that were healthy prior to the arrival of winter,” says lead author Chensheng Lu, associate professor of environmental exposure biology at the Harvard School of Public Health.

Imidacloprid and clothianidin are among the most widely used neonicotinoid pesticides, but many more are on the market. These systemic pesticides make all parts of a plant poisonous to insects — even the pollen and nectar, which are gathered and consumed by honeybees and other pollinators. The effects can be fast or slow, depending on the dosage and whether other chemicals are included in the mix. In spring 2014, the bees in more than 80,000 hives were found dead or damaged after the bees worked California almond orchards in which neonicotinoid pesticides had been combined with other chemicals, all in keeping with the pesticide labels’ directions.

The European Food Safety Authority has banned the use of neonicotinoid pesticides, and the U.S. Fish and Wildlife Service announced this year that these potent chemicals will be banned in the 150-million-acre National Wildlife Refuge System by January 2016. Next up, we must demand that the U.S. Environmental Protection Agency ban these insecticides nationwide, too.

To take action by making your yard a safer place to be a bee, consult resources from the BEE Protective program, launched by the groups Beyond Pesticides and the Center for Food Safety.

Contributing editorBarbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on .

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