Pesticides Implicated in Bee Colony Collapse Disorder

photo by Bjorn Hermans

photo by Bjorn Hermans

Scientists at the European Food Safety Authority (EFSA) have issued a report aimed at enhancing the protection of bees stating three commonly used pesticides in the neonicotinoid class of insecticides – clothianidin, imidacloprid, and thiamethoxam – pose an “acute risk” to bee populations and should not be used in crops attractive to bees. The EFSA report stopped short of stating a clear, causal link between these pesticides and bee Colony Collapse Disorder (CCD), citing gaps in their research. Colony Collapse Disorder is a syndrome where worker bees vanish and their hives die. However, in March 2012 US scientists published an article, “In Situ Replication of Bee Colony Collapse Disorder,” in the Bulletin of Insectology, demonstrating the connection between imidacloprid and CCD, and evidence has been mounting in the scientific community for some time.

In the study, researchers replicated Colony Collapse Disorder by showing that, over time, repeated exposures to imidacloprid, even at low levels, kill off entire hives. Bees ingest pesticides from the nectar of treated plants or via the corn syrup commercial beekeepers use to feed hives derived from treated corn crops. Neonicotinoids target an insect’s nervous system, causing paralysis and death.

Bayer CropScience, manufacturer of clothianidin and imidacloprid predictably disputes these findings.

Neonicotinoids have long been suspected in CCD, along with parasites like the varroa mite and nosema ceranae, other pathogens like the Israeli acute paralysis virus (IVAP), and even poor diet and cellphone usage. Scientists have been investigating the phenomenon since 2006, when sharp rises in colony collapses were first noted. Bees are the primary pollinator for 80% of the world’s food crops. As colonies become more scarce, the costs to pollinate plants has gone up, in turn driving up food prices.


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