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 ?
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.
He said: "Between 1962 and 1971, the US military sprayed South Vietnam with approximately 76 million litres of defoliants - including Agent Orange - the Pentagon assuring South Vietnamese residents and its own troops it was harmless to humans.
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.
Washington, Apr 21 (ANI): A new study has revealed that people who have been exposed to Agent Orange, a herbicide and defoliant used during the Vietnam War, are at an increased risk of aggressive recurrence of prostate cancer.
In 2004 we showed the Agent Orange exhibition, which captured the harrowing effects of the defoliant used by soldiers on the Vietnamese people.
The survivors, called ''hibakusha'' in Japanese, are scheduled to hold a dialogue in Vietnam with victims of Agent Orange, a toxic defoliant used by U.
He then worked in the private sector until 1993, when he was diagnosed with lung cancer caused by his wartime exposure to the defoliant and had his left lung removed.
military personnel who sprayed the defoliant from airplanes, helicopters, and even from the backs of jeeps or on foot patrol.
Last year, he was placed on 100 percent medical disability because his Parkinson's and diabetes were linked to exposure to the defoliant Agent Orange in Vietnam, his wife said.
It is used as herbicide, fungicide, desiccant, defoliant and additives to animal's feeds.
Seven companies--the Dow Chemical Company, Monsanto, the Diamond Shamrock Corporation, Hercules, Uniroyal, T-H Agricultural & Nutrition Company and the Thompson Chemicals Corporation were commissioned by the US government under the Defense Production Act 1950 to develop a defoliant that would reveal the enemy's jungle positions and destroy their crops.