In case you have not heard about this, here is a good article on the subject via the New York Times:
Bees Vanish, and Scientists Race for Reasons By ALEXEI BARRIONUEVO
BELTSVILLE, Md., April 23 — What is happening to the bees?

More than a quarter of the country’s 2.4 million bee colonies have been lost — tens of billions of bees, according to an estimate from the Apiary Inspectors of America, a national group that tracks beekeeping. So far, no one can say what is causing the bees to become disoriented and fail to return to their hives.

As with any great mystery, a number of theories have been posed, and many seem to researchers to be more science fiction than science. People have blamed genetically modified crops, cellular phone towers and high-voltage transmission lines for the disappearances. Or was it a secret plot by Russia or Osama bin Laden to bring down American agriculture? Or, as some blogs have asserted, the rapture of the bees, in which God recalled them to heaven? Researchers have heard it all.

The volume of theories “is totally mind-boggling,” said Diana Cox-Foster, an entomologist at Pennsylvania State University. With Jeffrey S. Pettis, an entomologist from the United States Department of Agriculture, Dr. Cox-Foster is leading a team of researchers who are trying to find answers to explain “colony collapse disorder,” the name given for the disappearing bee syndrome.

“Clearly there is an urgency to solve this,” Dr. Cox-Foster said. “We are trying to move as quickly as we can.” LINK