Thousands of scientific sleuths have been on this case for the last 15 years trying to determine why our honey bees are disappearing in such alarming numbers. “This is the biggest general threat to our food supply,” according to Kevin Hackett, the national program leader for the U.S. Department of Agriculture’s bee and pollination program.

Until recently, the evidence was inconclusive on the cause of the mysterious “colony collapse disorder” (CCD) that threatens the future of beekeeping worldwide. But three new studies point an accusing finger at a culprit that many have suspected all along, a class of pesticides known as neonicotinoids.