Saturday, May 17, 2014

Neonicotinoids and CCD

Beekeepers have long suspected the role of the neonicotinoid insecticides in the great upsurge of honey bee colony die-offs that have continued since 2006. Named Colony Collapse Disorder, the loss of honey bee colonies has persisted for eight years in spite of efforts by researchers to identify a cause and by beekeepers to replenish their hive numbers. According to the Bee Informed Partnership’s recently released report,, annual losses have averaged an unsustainable level of nearly 30 percent. A relatively small-scale study by Harvard School of Public Health,, reveals interesting findings. Honey bee colonies exposed to either of two low levels of neonicotinoid insecticides, imidacloprid or clothianidin, abandoned their hives during the winter, defining symptoms of Colony Collapse Disorder. This report contrasts somewhat from the results of a previous study on the effect of pesticides that lead to susceptibility to the honey bee gut pathogen, Nosema ceranae. The larger study, reported in PLOS ONE,, finds large numbers and high levels of pesticides in honey bee hives. The researchers found 35 different pesticides in sampled honey bee pollen and high levels of fungicides.

Until recently, fungicides, chemicals designed to fight fungal infections, were considered safe for honey bees. Recent studies are finding fungicides to have an adverse effect on honey bee health, often making insecticides and miticides more toxic to bees. In the PLOS ONE study, fungicides were found to lead to Nosema infection. Needless to say, the search for the cause of Colony Collapse Disorder has revealed the complexity of the problem. There are many factors contributing to honey bee health, including nutrition, parasitic mites, pest insects, viral, fungal, and bacterial diseases, and environmental chemicals. Studies are finding insecticides, miticides, fungicides, and herbicides in the bee hives. Combinations of chemicals and breakdown products of chemicals are often highly toxic to bees. Peace Bee Farm has participated in a number of the studies. Today, catalpa trees secrete nectar from the flowers and nectaries on the leaves.