Postemergence Control of Weeds in Winter Rapeseed,Brassica napus, by DPX-A7881

Field experiments were established to determine the dose and timing of DPX-A7881 applied postemergence for control of weeds in winter rapeseed. Wild mustard and shepherdspurse were effectively controlled by DPX-A7881. Control of these weeds by DPX-A7881 was dependent upon growth stage. The later the growth stage at time of herbicide application the poorer the control. Fall applications of DPX-A7881 provided greater control of wild mustard and shepherdspurse seedlings compared to spring applications. The 0.010 kg ai ha -1 dose was as effective in controlling susceptible weed species as 0.030 kg ai ha -1 . Control of common lambsquarters and redroot pigweed by DPX-A7881 was poor. Regardless of timing or amount of herbicide applied, DPX-A7881 did not significantly reduce dry weights of either barnyardgrass or green foxtail. Doses of DPX-A7881 ranging from 0.010 to 0.030 kg ai ha -1 did not injure or adversely affect winter survival of rapeseed seedlings. Rapeseed yield and seed quality were not affected by DPX-A7881 applied postemergence.