Defoliants are herbicides that cause the leaves of plants to fall off quickly. Using them can make harvesting easier for some crops. Militarily they were u. a. used to defoliate trees during the Vietnam War to take cover from the enemy. In addition, defoliants were used to cut off the enemy from the supply of food by damaging plants. This led to environmental and health damage to a considerable extent.
Use in agriculture
Defoliants are used, among other things, before the harvest of cotton , soybeans or tomatoes . For this purpose, S , S , S -tributyltrithiophosphate (DEF), tributyltrithiophosphite (Merphos), sodium chlorate , magnesium chlorate , calcium cyanamide , sodium polyborates such as disodium octaborate , dimethylarsinic acid (cacodylic acid), dimethipine , diquat and paraquat were or are used.
Defoliants used in the military
Military defoliants were first developed in the United Kingdom . From 1940 onwards , the defoliants LN8 , LN14 , LN32 and LN33 , based on 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), were manufactured and later tested at Imperial Chemical Industries . The planned operation against the “ Third Reich ” did not materialize anymore due to the end of the war. In the late 1940s and early 1950s, the United Kingdom's armed forces used 2,4,5-T to fight Chinese partisans in Malaysia ("Malayan Emergency").
When the US government under John F. Kennedy was considering the use of defoliants in the Vietnam War in the early 1960s , US Secretary of State Dean Rusk used the British approach in Malaysia in the early 1950s as a precedent to justify this use . Since there were no international protests or other critical reactions at the time, the Kennedy administration did not regard the use of defoliants as a violation of international martial law .
As part of Operation Ranch Hand was then from 1961 by the US forces many thousands of tons of defoliants ( English defoliants used) in Vietnam. A calculation of the total amount of these funds applied between 1961 and 1971 showed more than 70 million liters. Some of the herbicides used were contaminated with 2,3,7,8-tetrachlorodibenzodioxin (TCDD), a teratogenic ( causing malformations in embryos ) and carcinogenic (carcinogenic) substance.
In order to avoid the unwieldy chemical names, the individual defoliants were named according to the color of the ribbon, which had been painted onto the corresponding 55 gallon storage barrel for identification purposes, i.e. Agent Pink, Agent Green, Agent Purple etc. (so-called "Rainbow Herbicides")
|Agent Pink||1961-1965||* 464.164|
|Agent Green||1961–1965 (?)||31,026|
|Agent Orange II||after 1968 (?)||** 3,591,000|
|Agent Blue (powder)||1962-1964||25,650|
|Agent Blue (aqueous solution)||1964-1971||4,715,731|
* Use of 50,312 l documented, another 413,852 l delivered, whereabouts unclear; ** delivered
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- Robert A. Darrow, George B. Truchalut, Charles M. Bartlett: Technical Report 79 - Oconus Defoliation Test Program (PDF) US Army Biological Center Fort Detrick, Frederick MD 1966
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- Robert Harris, Jeremy Paxman: A higher form of killing. The secret history of B and C weapons. 1986, pp. 161 + 297.
- Robert Harris, Jeremy Paxman: A higher form of killing. The secret history of B and C weapons. 1986, p. 160.
- Erin Blakemore: Agent Orange Wasn't the Only Deadly Chemical Used In Vietnam , history.com, September 14, 2017
- Robert Harris, Jeremy Paxman: A higher form of killing. The secret history of B and C weapons. 1986, pp. 163 + 297.
- On page 28: A 1961 Dean Rusk memo to President Kennedy showed the common belief that Britain previously set a precedent for wartime chemical defoliation. Rusk explained, from 1951 - 53 during the "emergency in Malaya [the British used] helicopters for destroying crops by chemical spraying." British defoliation had not prompted an international incident, and US officials believed that the world community would also tacitly approve their use of "weed killers." . In: Neil Shafer Oatsvall; War on Nature, War on Bodies: The United States' Chemical Defoliant Use During the Vietnam War and Its Consequences (PDF) North Carolina State University, 2008
- Jeanne Mager Stellman, Steven D. Stellman, Richard Christian, Tracy Weber, Carrie Tomasallo: The extent and patterns of usage of Agent Orange and other herbicides in Vietnam . In: Nature . tape 422 , no. 6933 , March 17, 2003, p. 681–687 , doi : 10.1038 / nature01537 ( online [PDF]).
- 55 gallons correspond to approx. 208 liters
- Rainbow Herbicides, Agent Orange, and VA Benefits , perkinslawtalk.com