Investigations of sulfosulfuron for cheat (Bromus secalinus) control in wheat (Triticum aestivum) and rotational crop response

Sixteen field experiments were conducted across Oklahoma to evaluate the effects of MON 37500 time of application on cheat control, wheat injury, and wheat yield. Wheat injury from MON 37500 when applied preemergence (PRE) was slight and was influenced by cumulative precipitation for 10 d following application. Wheat injury was more frequent with early versus late postemergence (POST) applications and was influenced by wheat growth stage and air temperatures before and after application. Cheat control averaged 75% (n=16 treatments with 4 to 6 replicates) when applied PRE and 88% (n=126 treatments with 4 to 6 replicates) when applied POST. Cheat control from MON 37500 applied POST was negatively influenced by cheat growth stage at application and by the mean low temperatures Oto 14 and Oto 21 days prior to application. MON 37500 applied PRE increased yields 52 and 66% in years one and two averaged over eight experiments each year. MON 37500 applied POST increased wheat yields 68 to 69% in years one and two when averaged over all applications in eight experiments each year. Timing applications at 21 to 42 and 168 d after wheat seeding both years maximized cheat control. Wheat yields were greater from fall POST applications