Selective pre-emergence herbicide. Prepn: B. W. Horrom et al., ZA 6800090; eidem, US 3534098; US 3640699 (1969, 1970, 1972 all to Rohm & Haas). Activity: K. L. Viste et al., Science 167, 280 (1970); C. Swithenbank et al., J. Agric. Food Chem. 19, 417 (1971). Metabolism: R. Y. Yih et al., Weed Sci. 18, 604 (1970); R. Y. Yih, C. Swithenbank, J. Agric. Food Chem. 19, 314, 320 (1971); J. D. Fisher, ibid. 22, 606 (1974). Carcinogenicity study: M. D. Reuber, Environ. Res. 23, 1 (1980).