Colony Collapse Disorder and Pesticides : The New Yorker

Silent Hives.

In 2006, when beekeepers began to report that their hives were suffering from a mysterious affliction, a wide variety of theories were offered to explain what was going on. The bees were suffering from a virus, or a fungus, or a mite, or from stress, or, according to one much publicized hypothesis, they were being addled by cell-phone signals.

In another study...seemingly healthy honey colonies were fed high-fructose corn syrup that had been treated with imidacloprid. Within six months, fifteen out of the sixteen hives that had been given the treated syrup were dead. In commercial beekeeping operations, bees are routinely fed corn syrup, and corn is routinely treated with neonicotinoids.
Of course, it's not so much the HCFS, as it is the neonicontinoid pesticides used on the corn that is made into HCFS.