This April 25, 2007 file photo shows a colony of honeybees at the Agriculture Department's Bee Research Laboratory in Beltsville, Md. A new federal report blames a combination of problems for a mysterious and dramatic disappearance of U.S. honeybees since 2006. The factors cited include a parasitic mite, multiple viruses, bacteria, poor nutrition and pesticides. Experts say having so many causes makes it harder to do something about what's called colony collapse disorder. The disorder has caused as much as one-third of the nation's bees to just disappear over the winter each year since 2006. The report was issued Thursday by the Agriculture Department and the Environmental Protection Agency. Photo: AP