Pesticide

A pesticide is a chemical, or sometimes biological agent such as a virus or bacteria, used to control, to repel, to attract, or to kill pests, which are organisms, including insects, weeds, birds, mammals, fish, and microbes, that compete with humans for food, destroy property, spread disease, or are considered a nuisance. Pesticides are usually, but not always, poisonous to humans.

History

Since before 500 BC humans have used pesticides to prevent damage to their crops. The first known use of pesticide was sulfur. By the 15th century, toxic chemicals such as arsenic, mercury, and lead were being applied to crops to kill pests. In the 17th century, nicotine sulfate was extracted from tobacco leaves for use as an insecticide. The 19th century saw the introduction of two more natural pesticides, pyrethrum, which came from crysanthemums, and rotenone, from the roots of tropical legumes.

Related Topics:
500 BC - Sulfur - 15th century - Arsenic - Mercury - Lead - 17th century - Nicotine sulfate - Tobacco - 19th century - Pyrethrum - Crysanthemum - Rotenone - Legumes

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In 1939, Paul Müller discovered that DDT was a very effective insecticide. It quickly became the most widely used pesticide in the world. However, in the 1960s, it was discovered that DDT was preventing many fish-eating birds from reproducing, which was a huge threat to biodiversity. DDT was also found to cause birth defects in animals and humans. DDT is now banned in at least 86 countries, but is still used in some developing nations to prevent malaria and other tropical diseases by killing mosquitos and other disease-carrying insects.

Related Topics:
1939 - Paul Müller - DDT - 1960s - Biodiversity - Birth defects - Malaria - Mosquitos

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Pesticide use has increased 50-fold since 1950, and 2.5 million tons of industrial pesticides are now used each year. The most widely used pesticides today are nonpersistent organophosphates, including glyphosate (the active ingredient in Roundup), which is currently the world's most used herbicide.

Related Topics:
1950 - Organophosphate - Glyphosate - Roundup

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