Pesticides and pest control
Background (Encyclopedia of Global Resources)
An animal or plant is regarded as a pest if it causes a nuisance or harm to humans or crops or otherwise negatively impacts human health, well-being, or quality of life. Pests such as silverfish consume paper and fabrics. Termites cause serious damage to houses and other wooden structures. Weeds, aphids, and snails play havoc with flower gardens. Beetles and fungi attack shade trees, timber, crops, orchards, and stored foods. Mosquitos, ticks, mites, and rodents transmit viruses and other disease organisms to humans.
Pest control is the ongoing process of managing insects, rodents, weeds, fungi, and other pest organisms where their lives intersect human lives. The twentieth century saw a rapid escalation in the use of chemical pesticides, which have become a mainstay of pest control. These chemicals have suppressed pest populations, increased crop yields, protected property, and kept disease in check. However, indiscriminate use of chemical pesticides has damaged the environment, which has led to governmental regulation of pesticides, outright bans on some substances, and increased interest in alternative pest-control methods.
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Types of Chemical Pesticides (Encyclopedia of Global Resources)
Chemical pesticides are often classed based on the organisms that they target. Avicides kill or repel bird pests. Rodenticides are for use against rats and mice. Acaracides and miticides target ticks and mites. Insecticides, the largest category of pesticide, are used against insects. Nematicides are used to kill nematodes, soil- and water-dwelling roundworms that are often parasitic on plants and animals. Fungicides are used to treat crops and other plants for fungal (and sometimes bacterial) conditions such as root rot, smut, gall, rust, and blight. Herbicides target the weeds and other unwanted vegetation that encroach on lawns, gardens, crops, and paths. Defoliants are a class of herbicide that induces leaf fall from trees and other plants.
Pesticides can also be categorized on the basis of chemical composition. Mineral pesticides such as arsenic, borax, copper, lead, and zinc were among the first pesticides employed by humans; these minerals have mostly been replaced by more efficient chemical compounds. Botanical pesticides are insecticidal substances derived from plants or are synthetic analogs to such substances. These include pyrethrins, chrysanthemum-derived insecticides which are not highly toxic to humans. Chlorinated hydrocarbons, which include chlorine, hydrogen, and oxygen in their chemical makeup, are highly effective poisons that do not readily degrade in the environment. Compounds such as...
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History of Use (Encyclopedia of Global Resources)
The “first generation” of chemical pesticides was the minerals and botanicals. In 1867, farmers in the United States began using Paris green, a then-common pigment containing arsenic and copper, to control outbreaks of the Colorado potato beetle. Lead arsenate was introduced as an insecticide in 1892. By the 1920’s, pesticide use in the United States had become commonplace, and concerns over arsenical residues in foods had begun to arise.
In 1939, the next generation of chemical pesticides was ushered in with the discovery of DDT’s insecticidal properties. The compound was first disseminated on a large scale during the Naples typhus epidemic of 1943-1944, and it found widespread use during the remainder of World War II. DDT and other potent broad-spectrum poisons were popular pesticides from the early 1940’s through the 1960’s. However, as concerns mounted over the environmental impact of these chemicals—contaminated watersheds; the dying off of beneficial species coupled with pests becoming pesticide resistant; the accumulation of pesticides in the bodies of higher animals, including humans; and poisoned food chains—use of chlorinated hydrocarbons fell into disfavor. Use of DDT and similar chemicals has been banned or restricted in many countries, including the United States.
The disadvantages of chemical pesticides have led to an increased interest in alternative pest-control methods. Biological...
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U.S. Regulation of Chemical Pesticides (Encyclopedia of Global Resources)
The Insecticide Act of 1910 prohibited adulteration of insecticides and fungicides. In 1947, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorized the United States Department of Agriculture (USDA) to oversee registration of pesticides and to determine their safety and effectiveness. In December, 1970, the newly formed U.S. Environmental Protection Agency (EPA) assumed statutory authority from the USDA over pesticide regulations. Under the Federal Environmental Pesticide Control Act of 1972, an amendment to FIFRA, manufacturers must register all marketed pesticides with the EPA before the product is released. Before registration, the chemicals must undergo exhaustive trials to assess their potential impact on the environment and human health. The EPA’s decision to grant registration is based on the determination that unreasonable adverse effects on human health or the environment are not anticipated within the constraints of approved usage. Beginning in October, 1977, the EPA has classified all pesticides to which it has granted registration as either a restricted-usage (to be applied only by certified pest control operators) or unclassified (general-usage) pesticide.
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Further Reading (Encyclopedia of Global Resources)
Carson, Rachel. Silent Spring. Drawings by Lois and Louis Darling. Boston: Houghton Mifflin, 1962.
Cremlyn, R. J. Agrochemicals: Preparation and Mode of Action. New York: Wiley, 1991.
Levine, Marvin J. Pesticides: A Toxic Time Bomb in Our Midst. Westport, Conn.: Praeger, 2007.
Lopez, Andrew. Natural Pest Control: Alternatives to Chemicals for the Home and Garden. Rev. ed. Malibu, Calif.: Invisible Gardener, 2005.
Matthews, G. A. Pesticides: Health, Safety, and the Environment. Ames, Iowa: Blackwell, 2006.
Stenersen, Jørgen. Chemical Pesticides: Mode of Action and Toxicology. Boca Raton, Fla.: CRC Press, 2004.
Ware, George W. Fundamentals of Pesticides: A Self-Instruction Guide. 3d ed. Fresno, Calif.: Thomson, 1991.
Ware, George W., and David M. Whitacre. The Pesticide Book. 6th ed. Willoughby, Ohio: MeisterPro Information Resources, 2004.
Whorton, James. Before “Silent Spring”: Pesticides and Public Health in Pre-DDT America. Princeton, N.J.: Princeton University Press, 1974.
U.S. Environmental Protection Agency. About Pesticides. http://www.epa.gov/pesticides/about/index.htm
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