glyphosate (several trade names)
Rate 0.75 to 2.25 lb ae/a (22 to 64 fl oz/a Roundup PowerMax 4.5SL)
Time Apply to quackgrass 6 to 8 inches tall before planting, or bean emergence.
Remarks Be aware that glyphosate is formulated as 3, 4, 4.17, 4.5, and 5 lb ae/gal. Take care to ensure using the correct amount of herbicide. Spring applications for perennial weed control are generally not very effective due to poor glyphosate translocation down to roots and rhizomes. Wait three or more days after application before tilling. Herbicide will not control weeds that emerge after application. Rain within 6 hours may reduce effectiveness of some brands. Some products require adding a nonionic surfactant; be sure to check the label. Control weed escapes in following years. Restricted entry interval (REI) is 4 or 12 hours depending on the glyphosate product used.
Caution Do not till before applying. Glyphosate applied after crop emerges will injure or kill crop. Do not apply to quackgrass stressed by drought, weather, or maturity. Do not plant crops other than those listed on label for one year after application. Do not feed or forage treated crops within eight weeks after application.
Site of action Group 9: inhibits EPSP synthase
Chemical family Glycine