defoliant

thumb|281x281px|Defoliants are used as an aid in the harvesting of certain crops such as cotton. thumb|2,4-D, one of the first chemical herbicides used as a defoliant.|281x281px thumb|U.S. Army Huey helicopter spraying [[Agent Orange over agricultural land during the Vietnam War.|283x283px]]

A defoliant is any herbicidal chemical sprayed or dusted on plants to cause their leaves to fall off. Defoliants are widely used for the selective removal of weeds in managing croplands and lawns. Worldwide use of defoliants, along with the development of other herbicides and pesticides, allowed for the Green Revolution, an increase in agricultural production in mid-20th century. Defoliants have also been used in warfare as a means to deprive an enemy of food crops and/or hiding cover, most notably by the United Kingdom during the Malayan Emergency and the United States in the Vietnam War. Defoliants were also used by Indonesian forces in various internal security operations.