Colony collapse disorder (CCD) is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of disappearances of Western honey bee colonies in North America in late 2006.[1] Colony collapse is significant because many agricultural crops worldwide are pollinated by bees. Bees are responsible for pollination of approximately one third of the United States' crop species.

European beekeepers observed similar phenomena in Belgium, France, the Netherlands, Greece, Italy, Portugal, and Spain,[2] and initial reports have also come in from Switzerland and Germany.

The cause or causes of the syndrome are unknown.

http://en.wikipedia.org/wiki/Colony_collapse_disorder