When I was a graduate student at the University of Kansas, the pesticide DDT was very much on my mind. My assistantship in 1953 involved research on the evolution of DDT-resistance in fruit flies. It quickly became clear to all of us in this research group that the broadcast use of pesticides was a losing and dangerous game. When I attempted to raise butterflies in New Jersey in the 1940s, bringing food plants in from nature usually resulted in the caterpillars dying. In those days, widespread spraying of DDT to control mosquitoes coated much of the countryside with poison. In the lab it was easy to use selection to make flies impervious to DDT in some 10 generations, or, in contrast, so susceptible that they would drop dead at a whisper of that “miracle” chemical’s name. Evolution of resistance tended to make continuous use of any pesticide inefficient. The usual response of the chemical industry was to recommend increasing the dose or to substitute more toxic compounds, making pest control even more expensive and dangerous.