Andy Bradshaw, left, his grandfather, Howard Bradshaw, and Isaias Corona working with bees this year near Visalia, Calif.
...The die-offs, in which adult bees typically vanished without returning to hives, were reported by about a fourth of the nation’s commercial beekeepers. The losses captured public attention as rumors swirled about causes, like climate change, cellphone signals and genetically-modified crops. Scientists have rejected those theories....
