http://www.newsweek.com/flupyradifurone-bee-safe-pesticide-bees-1390422

In recent years, concern has grown about the effects of agricultural pesticides on the health of bees, with much of the attention focused on so-called "neonicotinoids," or “neonics” for short.

As the use of neonics has become more and more restricted, manufacturers have developed pesticides that are considered “bee safe.” However, one of these substances, flupyradifurone (FPF)—sold under the name Sivanto—may cause harm to bees when a common fungicide is also present. That's according to a study published in the journal Proceedings of the Royal Society B: Biological Sciences.