On Sunday morning, the South Carolina honey bees began to die in massive numbers. Death came suddenly to Dorchester County, S.C. Stressed insects tried to flee their nests, only to surrender in little clumps at hive entrances. The dead worker bees littering the farms suggested that colony collapse disorder was not the culprit — in that odd phenomenon, workers vanish as though raptured, leaving a living queen and young bees behind. Instead, the dead heaps signaled the killer was less mysterious, but no less devastating. The pattern matched acute pesticide poisoning. By one estimate, at a single apiary — Flowertown...