EARLY WATERGRASS (Echinochloa oryzoides) AND LATE WATERGRASS (Echinochloa phyllopogon) CONTROL WITH FORAMSULFURON

Early watergrass and late watergrass are predominant weeds of rice fields but can also occur in corn fields where it follows rice in rotation. Pot experiments were conducted to evaluate control of early watergrass and late watergrass with foramsulfuron applied alone and in mixture with dicamba,MCPA, sulcotrione, and mesotrione. Foramsulfuron applied at 45 g a.i. ha-1 provided 82% of early watergrass and 76% of late watergrass control at 3- to 4-leaf growth stage, whereas efficacy was only 71% for early watergrass and 62% for late watergrass at 5- to 6-leaf growth stage. Increased application rate of foramsulfuron provided better control of both species at any growth stage, with the highest application rate (59 g a.i. ha-1) providing maximum control of both species. Mixtures of foramsulfuron with dicamba or MCPA showed lower control of both species than foramsulfuron appliedalone. Moreover, sulcotrione applied in mixture with foramsulfuron improved control of both species, whereas the addition of mesotrione did not affect control of both species compared with foramsulfuron applied alone. Satisfactory control of early watergrass and late watergrass in corn can be achieved with increased application rates of foramsulfuron applied preferably at early growth stage. Mixtures offoramsulfuron with either dicamba or MCPA can reduce considerably the efficacy of foramsulfuron on both early watergrass and late watergrass. On the other hand, mixtures of foramsulfuron with either sulcotrione or mesotrione can be used for broadening spectrum of control without affecting negatively foramsulfuron activity on these grasses.