Published online by Cambridge University Press: 12 June 2017
Early postemergence applications of 2,6-dichlorobenzonitrile (dichlobenil) granules at 15 lb/A controlled 97 to 99% of dwarf waterlily (Nymphaea tetragona Georgi) in a shallow lake for 3 years. Dichlobenil alone was superior to a combination of dichlobenil and (2,4-dichlorophenoxy)acetic acid (2,4-D) for the control of dwarf waterlily and western yellow waterlily (Nuphar polysepalum Engelm). Reinfestation was more rapid on plots 25 by 25 ft in size than on plots 50 by 50 ft in size. When a high degree of control was maintained for 2 or 3 years, rhizomes of dwarf waterlily and a 1 to 2-ft layer of hydrosoil floated to the lake surface 17 months after dichlobenil was applied.