NICOSULFURON AND PRIMISULFURON ERADICATE RHIZOME JOHNSONGRASS (SORGHUM-HALEPENSE) IN CORN (ZEA-MAYS) IN 3 YEARS

Field studies were conducted at Carbondale, IL from 1992 to 1994 to ev aluate rhizome johnsongrass control in field corn with nicosulfuron an d primisulfuron applied POST without or with EPTC applied PPI. EPTC ap plied PPI at 4480 and 6720 g ai/ha plus dichlormid controlled johnsong rass 38 and 60% in 1992 and 29 and 41% in 1993, respectively, and 0% i n 1994. EPTC did not decrease johnsongrass rhizome weight, length, or number of nodes in ally year. Nicosulfuron at 35 g/ha and primisulfuro n at 40 g/ha applied to 38-cm tall plants controlled 94 to 100% and 85 to 100%, respectively, from 1992 to 1994. Plots treated for three con secutive seasons with nicosulfuron or primisulfuron did not have any r hizomes. Corn yield was more than double in nicosulfuron and primisulf uron plots compared with control plots.