Glyphosate and package mixtures of glyphosate plus dicamba or 2,4-D were evaluated for the selective control of jointed goatgrass and downy brome in seeded perennial grasses. Glyphosate at 560, glyphosate plus dicamba at 550 + 220, and glyphosate plus 2,4-D at 420 + 350 and 570 + 470 g ai/ha controlled 90% or more jointed goatgrass in 1988 and 1991. Glyphosate plus 2,4-D at 150 + 120 and 280 + 240 g/ha were the only treatments that controlled less than 90% of jointed goatgrass in 1991. In 1988, glyphosate at 210 g/ha and glyphosate plus dicamba at 210 + 80 g/ha were the only treatments that controlled less than 90% of downy brome. Glyphosate at 210, 280, 420, and 560 g/ha, glyphosate plus dicamba at 210 + 80, 280 + 110, 420 + 170, and 550 + 220 g/ha, and glyphosate plus 2,4-D at 150 + 120, 280 + 240, 420 + 350, and 570 + 470 g/ha controlled 90% or more downy brome in 1990. Pubescent wheatgrass and crested wheatgrass were stunted or killed if they were growing when herbicides were applied.
