By Dr. Mercola (link)

Honeybees are perhaps one of the least recognized workers in the agricultural industry. They contribute $15 billion in annual agriculture revenue to the U.S. economy alone, as a full one-third of the U.S. food supply depends on them pollinating crops.
Apple orchards, for instance, require one colony of bees per acre in order to be adequately pollinated. So, unless the mysterious disappearance of bees is reversed, major food shortages could result.
This is not a brand new issue.
For several years now, scientists have been struggling to determine why bee colonies across the world are disappearing—a phenomenon dubbed colony collapse disorder (CCD). In a series of reports and videos, PBS talks about the bee colony devastation and its impact on the food supply and U.S. agriculture.
For a great review, please watch the PBS episode, Silence of the Bees.

Also watch the full episode. See more Botany of Desire.