Honeybee Killer Finally Found Colonies collapsing due to fungus-virus combination By Evann Gastaldo, Newser Staff Posted Oct 7, 2010 7:30 AM CDT 25 comments Comments Partially dissected honeybees are seen at the United States Department of Agriculture's Bee Research Laboratory, in this April 25, 2007 file photo. (AP Photo/Haraz N. Ghanbari) (Newser) – For years, experts have been trying to figure out what is killing all the honeybees—and they may finally have an answer. Since 2006, 20% to 40% of US bee colonies have collapsed, and suspected causes have included genetically modified corn, pesticides, and bad weather. New research, however, points to a combination of factors: A fungus and a virus working together. The breakthrough was achieved by bee experts who teamed up with military scientists to study dead bees, the New York Times reports. Fungus has been named as a possible suspect before, as have RNA-based viruses. But this research uncovered a new, DNA-based virus that proliferates in cool, damp weather—just like the fungus does—and the combination was found in all the affected colonies studied. It is thought that the virus and fungus both damage the bees’ guts, compromising their nutrition, although more research is needed to determine exactly how the deadly combination is killing the bees.