Colony collapse disease has killed thousands of bees . Scientists suspect a disease may combine with other factors to collapse colonies . It first showed up in 2004 , as bees were imported from China . $ 15 billion in U.S. is each year dependent on bees for pollination .
Colony collapse disorder has killed millions of bees . Scientists suspect a virus may combine with other factors to collapse colonies . Disorder first cropped up in 2004 , as bees were imported from Australia . $ 15 billion in U.S. crops each year dependent on bees for pollination .