It seems, according to the BBC, that a virus called the Israeli Acute Paralysis Virus (IAPV) is the likely culprit in the decline of the North American honeybee. Accusations were hurled at mobile phone radiation, pesticides from genetically modified crops, and also to climate change. To date, 50% to 90% of U.S. commercial bee colonies have been affected.
Although it's nice that mobile phone radiation seems to be in the clear, the problem is a very serious one. The cause of the virus is so far undetermined. Honeybee use in U.S. agricultures is worth an estimated $14 billion.