Pesticides are among the few toxic substances deliberately added to our environment. They are, by definition, toxic and biocidal, since their purpose is to kill or harm living things. Pesticides are ubiquitous global contaminants found in air, rain, snow, soil, surface and ground water, fog, even the Artctic ice pack. All living creatures tested throughout the world are contaminated with pesticides—birds, fish, wildlife, domestic animals, livestock, and human beings, including newborn babies.
The term pesticide is generic, and different classes are named for the pest they control: insecticides (e.g., ants, aphids, beetles, bugs, caterpillars, cockroaches, mosquitoes, termites), herbicides (e.g., weeds, grasses, algae, woody plants), fungicides (e.g., mildew, molds, rot, plant diseases), acaricides (mites, ticks), rodenticides (rats, gophers, vertebrates), picisides (fish), avicides (birds), and nematocides (microscopic soil worms).
Use of sulfur and arsenic as pesticides dates back to ancient times. Botanicals such as nicotine (tobacco extract) date from the sixteenth century, and pyrethrum (from a type of chrysanthemum) since the nineteenth century. In the United States, Paris green (copper-aceto-arsenite) was first used in 1867 to control the Colorado potato beetle. In 1939 there were 32 pesticide products registered in the United States, primarily inorganic compounds containing arsenic, copper, lead, mercury, nicotine, pyrethrums, and sulfur.
Widespread use of petrochemical-based synthetic pesticides began in the 1940s. Swiss chemist Paul Mueller discovered the insecticidal properties of dichlorodiphenyltrichloroethane (DDT) in 1939. Dusting of allied troops during World War II to kill body lice averted a typhus epidemic, making it the first war in history in which more soldiers died of wounds than of disease. DDT was marketed for commercial use in the United States in 1945. German scientists experimenting with nerve gas during World War II synthesized the first organophosphate insecticide, parathion, marketed in 1943. The phenoxy herbicides 2,4-dichlorophenoxy acetic acid (2,4-D) and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) were introduced in the 1940s, carbaryl and other N-methyl carbamate insecticides in the 1950s, the synthetic pyrethroid insecticides in the 1960s, and genetically modified products (plant-incorporated protectants, PIPs) in the 1990s.
The first serious challenge to synthetic pesticides was the 1962 publication of Silent Spring by wildlife biologist Rachel Carson.1
She documented environmental persistence, bioaccumulation in human and animal tissues, severe toxic effects on birds, fish, and other nontarget species, and potentially devastating ecological, wildlife, and human health effects of DDT and related chlorinated hydrocarbon insecticides.
In 1970, authority for administration and enforcement of the federal pesticide law was transferred from the U.S. Department of Agriculture to the newly created Environmental Protection Agency (EPA).
In 2001 there were 18 major basic producers of pesticides in the United States, 100 smaller producers, 150–200 major formulators, 2000 smaller formulators, 250–300 major distributors, 16,900 smaller distributors and establishments, and 40,000 commercial pest control companies.