The cause of the mysterious deaths of large numbers of honey bees across the United States that began in 2006 has apparently been discovered.
Scientists from the Army’s Edgewood Chemical Biological Center and the University of California at San Francisco identified both a virus and a parasite that are associated with the massive decline in the honey bee population.
See “Scientists Identify Pathogens That May Be Causing Global Honey-Bee Deaths,” Science Daily, April 26 (thanks to CB).
Update: As a commenter noted, this is old news. The Science Daily story dates from April 2007!
Additional background on the issue is available in “Recent Honey Bee Colony Declines” (pdf), Congressional Research Service, updated August 14, 2007.