NUTSEDGE (CYPERUS SPP.) CONTROL AND PERENNIAL RYEGRASS OVERSEEDING TOLERANCE TO SP25052

摘要

Purple and yellow nutsedge control trials were conducted in Abilene/Midland,TX and Knoxville,TN,while perennial ryegrass overseeding trials were conducted in Lubbock,TX during the summer of 2011.The objectives of our research were to evaluate SP25052 for the control of purple and yellow nutsedge,determine the safety of SP25052 on bermudagrass turf,and identify the effect of SP25052 soil residual activity on perennial ryegrass establishment.Bermudagrass phytotoxicity never exceeded 3% on any observation date and all bermudagrass recovered within 7 d of herbicide application,regardless of field trial.SP25052 and SP25052 + MSO exhibited 82 to 83% purple nutsedge control 8 weeks after initial treatment (WAIT),regardless of treatment.Purple nutsedge control with SP25052 + MSO + AMS,SP25052 + NIS,trifloxysulfuron,and sulfosulfuron was 90 to 99% 8 WAIT,regardless of herbicide treatment.Trifloxysulfuron and sulfosulfuron maintained similar control of purple nutsedge (92 to 94%) 12 WAIT,while control with all SP25052 treatments decreased.The greatest amount of control with SP25052 treatments was observed with SP25052 + MSO + AMS (73%) followed by (fb) SP25052 + MSO (48%) and SP25052 + NIS (45%) 12 WAIT.SP25052 applied alone exhibited the least amount of purple nutsedge control (29%) 12 WAIT.All treatments exhibited ≥ 99% yellow nutsedge control 8 WAIT.SP25052 and SP25052 + MSO + AMS exhibited similar yellow nutsedge control (93%) to dicamba + iodosulfuron + thiencarbazone (95%),trifloxysulfuron (97%),and sulfosulfuron (100%) 12 WAIT.Control decreased slightly to 89% with applications of SP25052 + MSO and SP25052 + NIS 12 WAIT.SP25052 rate and application timing had an effect on perennial ryegrass establishment.Untreated check plots exhibited 80% ryegrass cover on 14 Dec.2011.Similar ryegrass cover (75 to 76%) was observed on 14 Dec.2011 in plots sprayed with SP25052 at 136 g ai ha-1 applied 6 and 8 weeks before overseeding (WBO).Ryegrass cover in response to SP25052 at 136 g ai ha-1 applied 4 and 2 WBO was 45 and 36%,respectively.No SP25052 treatment at the 271 g ai ha-1 rate exhibited similar ryegrass cover to the untreated check,regardless of application timing.Ryegrass cover in response to SP25052 at 271 g ai ha-1 applied 8,6,4,and 2 WBO was 54,40,43,and 16%,respectively.SP25052 may be an alternative for the control of yellow and purple nutsedge,but applications may be limited to rates of 136 g ai ha-1 made 6 WBO when utilized in overseeded bermudagrass turf.