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2,4-D was first reported in 1944 by Franklin D-Jones at the C. B. Dolge Company in Connecticut. [5] The biological activity of 2,4-D as well as the similar hormone herbicides 2,4,5-T, and MCPA were discovered during World War II, a case of multiple discovery by four groups working independently under wartime secrecy in the United Kingdom and the United States: William G. Templeman and ...
MCPA (2-methyl-4-chlorophenoxyacetic acid) is a widely used phenoxy herbicide introduced in 1945. It selectively controls broad-leaf weeds in pasture and cereal crops . The mode of action of MCPA is as an auxin , which are growth hormones that naturally exist in plants.
US Geological Survey estimate of 2,4-D use in the USA to 2019. The use of herbicides in US agriculture is mapped by the US Geological Survey. As of 2019, 2,4-D was the most used of the auxins. 45,000,000 pounds (20,000,000 kg) were sprayed that year, [5] compared to 2,000,000 pounds (910,000 kg) of the next most heavily applied, MCPA. [6]
It is often used in combination with other chemically related herbicides such as 2,4-D, dicamba, and MCPA, which mimic the plant hormone IAA (auxin) and kill most broadleaf weeds by causing uncontrolled growth. The United States Environmental Protection Agency has classified mecoprop as toxicity class III - slightly toxic. [4]
In this way 2-methyl-4-chlorophenoxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) are produced. It is the precursor to the herbicide glyphosate and dimethoate. Chloroacetic acid is converted to chloroacetyl chloride, a precursor to adrenaline (epinephrine).
Today, only R-dichlorprop (also called dichlorprop-p or 2,4-DP-p) and its derivatives are sold as pesticides in the United States. Dichlorprop is a carboxylic acid, and like related herbicides with free acid groups, it is often sold as a salt or ester. Currently, the 2-ethylhexyl ester is used commercially. The butoxyethyl and isooctyl esters ...
Many questions exist about herbicides' health and environmental effects, because of the many kinds of herbicide and the myriad potential targets, mostly unintended. For example, a 1995 panel of 13 scientists reviewing studies on the carcinogenicity of 2,4-D had divided opinions on the likelihood 2,4-D causes cancer in humans. [43]
2,4-DB or 4-(2,4-dichlorophenoxy)butyric acid is a selective systemic phenoxy herbicide used to control many annual and perennial broad-leaf weeds in alfalfa, peanuts, soybeans, and other crops. Its active metabolite , 2,4-D , inhibits growth at the tips of stems and roots.