Pesticide production
Few pesticides were available before 1940:
–Some natural insect poisons extracted from plants
–Early insecticides were nicotine sulfate obtained from tobacco, retenone from the tropical derris plant and garlic oil
–A few inorganic compounds of lead and arsenic
Large scale use of pesticides began after WWII with the introduction of DDT
DDT
At its introduction it seemed to be an ideal insecticide:
–Cheap to produce
–Apparently non-toxic to humans and other mammals
–Did not breakdown easily → continued to kill insects for a long time after application
