Application timing determines giant foxtail (Setaria faberi) and barnyardgrass (Echinochloa crus-galli) control in no-till corn (Zea mays)

Field studies were conducted from 1996 to 1998 to evaluate grass control in no-till corn (Zea mays) with herbicides applied early preplant (EPP), pree mergence (PRE), and postemergence (POST) at the Belleville Research Center at Belleville, IL. Grass control was affected by application timing rather than herbicide. The herbicides applied PRE provided more consistent giant f oxtail (Setaria faberi) and barnyardgrass (Echinochloa crus-galli) control (90 to 98%) than the same herbicides applied EPP (0 to 92%). There also was no difference in giant foxtail and barnyardgrass control between the emuls ifiable concentrate (EC) formulation and microencapsulated (ME) formulation of acetochlor. Rimsulfuron plus thifensulfuron applied POST provided 90 to 97% control of giant foxtail and barnyardgrass. Metolachlor, EC-acetochlor , SAN 582H, and rimsulfuron plus thifensulfuron provided 85 to 92% control of yellow nutsedge (Cyperus esculentus) compared with 63 to 74% control for BAY FOE 5043 plus metribuzin and ME-acetochlor. Corn grain yield was great er with herbicides applied either PRE or POST than applied EPP Grass contro l and grain yield were greater with herbicides applied either PRE or POST c ompared with EPP.