posted by eric darling on .
After spraying crops with DDT for several years, farmers found that populations of insect pests rebounded. One reason was that insects had developed resistance to the insecticide. propose another reanson from the phenomenon
That the insect predators had been killed off?
You might want to read Rachel Carson's Silent Spring. There are summaries on the web, but if you are interested in this topic this book is a good starting point.