Bayer CropScience AG has operated as a subsidiary of Bayer AG, a company founded in 1863 and headquartered in Leverkusen, Germany, since June 3, 2002. Located in Monheim am Rhein, Germany, the company originally began as Aventis CropScience AG in 1999 and changed its name following its purchase by Bayer.Bayer CropScience AG ranked third in the global market for herbicide manufacturing as of November 2010, according to its website. It was one of the leading producers of herbicide products for the cereals, corn, sugar beet and rice at that time. The company's more than 100 brands of herbicides include Mesomaxx, Atlantis, Option, Maister, Hussar, Quartz and Corvus. Bayer CropScience AG also manufactures pesticides, insecticides fungicides and other agricultural chemicals.