While pesticides had existed for centuries, World Wars I and II served as a watershed for the modern agri-chemical industry. Chemicals and technologies developed for warfare, were later focused on the farm.
Crop dusting on cotton began in the Mississippi Delta as early as 1922.
Swiss chemist Paul Müller discovered the insecticidal properties of DDT in 1939, an innovation that later earned him the Nobel Prize.
German scientists experimenting with nerve gas during World War II synthesized the organophosphorous insecticide Parathion, marketed in 1943, and still widely in use today. Throughout the 1950s and 60s, these types of chemicals became major pest control agents.
Silent Spring, Rachel Carson's landmark challenge to the abuse of synthetic pesticides, was published in 1962, and initiated the movement toward agrochemical regulation that is still fiercely debated.
Today's pesticides are designed to persist for shorter periods in the environment and are supposedly less lethal than the early days of calcium arsenate and DDT.
Yet more pesticides are used in more countries than ever before - over $27 billion annually.
In response to increasing resistance to chemicals, one corporation has marketed a new variety of "bio-engineered" cotton which can withstand even greater applications of herbicides.