defoliant


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Related to defoliant: paraquat, Agent Orange

defoliant,

any one of several chemical compounds that, when applied to plants, can alter their metabolism, causing the leaves to drop off. In agriculture defoliants are used to eliminate the leaves of a crop plant so they will not interfere with the harvesting machinery. Their main military objective is to deprive the enemy of cover. In addition they have been used on food crops that have been considered potential sustenance for the enemy. Unfortunately, defoliants are not discriminating chemical weapons. Normally applied from the air, they are difficult to confine to a desired area and may thus contaminate watercourses, with disastrous effects on fish and other aquatic life. Human beings are also known to suffer toxic effects from them. Further, indigenous populations have suffered severe malnutrition when their food crops have been defoliated to prevent their use by the enemy. Possibly the severest and most long-lasting side effect of military defoliation is the disruption of the fragile jungle ecosystem. Contrary to appearances, the soils that underlie rain forests are not abundant in plant nutrients. Therefore, the ecosystem generally conserves and recycles the nutrients that do exist. Any massive disruption, such as killing or interfering with the metabolism of large numbers of plants, inevitably causes large amounts of nutrients to be washed away by rainfall. Also, when sunlight, which would normally be blocked by the leaves, falls on the claylike soil of the jungle, the soil bakes and becomes very hard. These conditions operate against reestablishment of normal vegetation. During the Vietnam War, U.S. forces used the defoliant Agent OrangeAgent Orange,
herbicide used by U.S. forces during the Vietnam War to expose enemy guerrilla forces in forested areas. Agent Orange contains varying amounts of dioxin. Exposure to the defoliant has been linked with chemical acne, non-Hodgkin's lymphoma, Hodgkin's disease,
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, which is widely thought to have led to cancer and other side effects among military personnel and civilians.

defoliant

[dē′fō·lē·ənt]
(materials)
A chemical sprayed on plants that causes leaves to fall off prematurely.
References in periodicals archive ?
Defoliants that contain horticultural vinegar can be used in place of agricultural chemicals--some of them confirmed carcinogens--that harm wildlife, pets, and people.
Mitchell's work has centred on allegations that Agent Orange, the defoliant used by US forces to rob Vietcong fighters of jungle cover and crops, is a problem of today, particularly in Okinawa, which was a major supply hub for the US military in the Vietnam con-flict.
Swansea-born Jon Mitchell, pictured, has made allegations on Japanese TV and in publications including the Japan Times that defoliants including Agent Orange were buried in Okinawa following the conflict and that they continue to pose a massive threat to health.
The US compensates its veterans exposed to the defoliant but not Vietnamese nationals and a lawsuit against US manufacturers was dismissed in 2007.
The defoliants were sprayed over vast swathes of jungle in South Vietnam in an attempt to flush out Viet Cong communist guerrillas by depriving them of tree cover and food.
asp) the issues faced by servicemen exposed to the defoliant, it has been reluctant to confirm that up to 4 million Vietnamese were also affected by the toxic chemicals, alleging that other environmental factors could be to blame for their health issues.
Agent Orange is a defoliant containing dioxin that the US used during the Vietnam war.
Introduced by French colonists, and soon exploited by international businesses including the French tire company Michelin, Vietnamese rubber trees were decimated by Agent Orange, a substance used by the American military as a defoliant in an attempt to deprive the Vietcong of ground cover.
My ephemeral office was a former war zone and our camp had no trees because some 40 years earlier it had been stripped bare by that destructive defoliant, Agent Orange.
I was telling him about the terrible effects of "Agent Orange", the defoliant sprayed extensively by the US Air Force on the forests of the south of Vietnam in the late 1960s: Cancers in people directly exposed and gross abnormalities in their children.
Singapore is the second destination for the ship which has already called at Danang in Vietnam where the survivors and some other passengers visited a rehabilitation center for survivors of the Vietnam War who are suffering from serious disabilities as a result of exposure to the defoliant ''Agent Orange'' that was used by the United States during the war.