The beginning of the chemical weeding of farmland can be traced back to the late 19th century, when the control of European grape downy mildew, the occasional discovery of Bordeaux can harm some cruciferous weeds without harming cereal crops; France, Germany, the United States also found that sulfuric acid and copper sulfate and other herbicides, and used in wheat and other places weeding. The organic herbicide period began in 1932 with the discovery of selective herbicide-hydroquinone. The advent of the the 1940s 2, 4-drops greatly facilitated the rapid development of the organic herbicide industry. The synthesis of glyphosate in the 1971 is a major breakthrough of Organophosphorus herbicides, which has the characteristics of broad killing grass and no pollution to the environment. Combined with the emergence of a variety of new dosage forms and new technologies, the weeding effect is greatly improved. In 1980, the world's herbicides accounted for 41% of total pesticide sales, surpassing pesticides and jumping first.
