Purple nutsedge (Cyperus rotundus L.) plants from tubers uniformly planted in fumigated soil were treated with 2,4-D [(2,4-dichlorophenoxy)acetic acid], paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), or dinoseb (2-sec-butyl-4-6-dinitrophenol). Repeated applications were made as required on the 1972 and 1973 plantings for one growing season. Emerged plants and their parent tubers were killed by four (1972) or five (1973) applications of paraquat. Three applications of 2,4-D were required for control in 1972. In 1973, a single treatment of 2,4-D afforded almost complete control. Three applications of dinoseb were required in 1972, but five were required in 1973.