Is a "cocktail" of "safe" pesticides killing off bee colonies?
Key Excerpts from Article on Website of CBS News
Posted: November 21st, 2016
Bee colonies have been dying off in high numbers, with suspicion falling on agricultural pesticides like herbicides and fungicides, as main factors behind the declines. Now, a new study out of the University of Maryland is the first to look at how a cocktail of all of various pesticides could be impacting bee colonies over time. Our results fly in the face of one of the basic tenets of toxicology: that the dose makes the poison, study senior author Dennis van Engelsdorp, an assistant professor of entomology at the University of Maryland, said. We found that the number of different compounds was highly predictive of colony death, which suggests that the addition of more compounds somehow overwhelms the bees ability to detoxify themselves. The study looked at 91 honey bee colonies that were owned by three migratory commercial beekeepers over one farming season. The research team examined 93 pesticide compounds that were found in the colonies throughout the season. These compounds were found building up in the bees wax in processed pollen, [as well as] in the bodies of nurse bees. The researchers ... measured three key things: the total number of pesticides, the total number of pesticides that were above a minimum level of toxicity, and each colonys hazard quotient, which factors in the hazard posed by the total toxicity of all pesticides present in the colony. What did the researchers find? Unfortunately, all three measures corresponded with a higher probability of colony death or the loss of the queen bee.
Note: This study was published in Nature Scientific Reports, and found that some compounds regarded as "bee-safe" could be a major contributors to honey bee colony losses. Prior to this, neonicotinoid pesticides were found to be connected to colony collapse disorder. Bayer, a major manufacturer of this pesticide, attempted to cover up the connection between its products and the massive die off of bees.