In 1966 Dr. C. A. Johansen wrote f or Bee World a Digest on bee poisoning, its effects and prevention, with an annotated list of 92 insecticides. Since then, much work has been done in many countries to reduce the hazards of insecticides to bees. In this article Dr. Johansen explains some of the advances, and setbacks. He refers especially to the USA, where the large-scale methods of agriculture and the high degree of mechanization amplify some of the problems. But ignorance is the greatest enemy of all, and many bees are now being killed by insecticides in developing countries where availability of materials has outstripped knowledge about their proper use.