| Abstract/Contents: | "A field study was conducted on a roadside site in Tift County, Georgia in 1995 to evaluate the potential of AC 263,222 (proposed name imazameth) applied alone and tank-mixed with various herbicides for growth regulation of 'Pensacola' bahiagrass (Paspalum notatum Flugge). Single treatments consisted of AC 263,222 at rates of 0.032, 0.047, 0.063, 0.094 and 0.125 lbs. ai/A and sulfometuron at 0.023 lbs. ai/A. Tank mix treatments consisted of AC 263,222 at 0.047 lbs. ai/A tank-mixed with glyphosate at 0.375 lbs. ai/A, pendimethalin at 2.0 lbs. ai/A, dicamba at 0.25 lbs. ai/A, imazapyr at 0.004 and 0.008 lbs. ai/A, or glyphosate at 0.15 + 2,4-D amine at 0.25 lbs. ai/A. A nonionic surfactant at 0.25% was included with all treatments. Herbicides were applied with a tractor mounted CO₂ sprayer, calibrated at 20 gpa, on April 25, 1995. At the time of herbicide application, bahiagrass was drought stressed and no seedheads were present. Treatments were arranged in a randomized complete block design with three replications. Data recorded included: color, where 0 = no effect and 100 = brown grass; density, where 0 = no effect and 100 = total loss of bahiagrass stand; and seedhead suppression, where 0 = no effect and 100 = total elimination of seedheads. Data were collected at various time intervals up to 16 weeks after application. AC 263,222 at rates ≥0.063 lbs. ai/A caused color reductions similar to sulfometuron at 2 and 4 WAT (weeks after treatment). By 8 WAT, AC 263,222 at rates ≥0.063 lbs. ai/A reduced color more than sulfometuron. AC 263,222 tank mixtures with pendimethalin, dicamba, imazapyr, glyphosate and glyphosate + 2,4-D reduced color more than AC 263,222 at 0.047 lbs. ai/A applied alone through 4 WAT. Similar to sulfometuron, AC 263,222 at rates ≤0.063 lbs. ai/A slightly reduced bahiagrass density. However, AC 263,222 at 0.094 and 0.125 lbs. ai/acre reduced density 18 and 42%, respectively, at 16 WAT. Tank mixtures of AC 263,222 with all herbicides, except glyphosate, reduced density similar to AC 263,222 at 0.047 lbs. ai/A applied alone. The tank mix of AC 263,222 and glyphosate reduced density 43 and 12% at 12 and 16 WAT, respectively. AC 263,222 at all rates and sulfometuron were equally effective in suppressing bahiagrass seedheads for up to 8 WAT. AT 16 WAT, AC 263,222 at rates ≥ 0.047 lbs. ai/A reduced seedhead emergence more than sulfometuron. Tank mixtures of various herbicides with AC 263,222 reduced seedheads similar to that observed for AC 263,222 at 0.047 lbs. ai/A applied alone for 12 WAT. At 16 WAT, tank mixtures of AC 263,222 with glyphosate, glyphosate + 2,4-D, and imazapyr at 0.008 lbs. ai/A reduced seedheads more than AC 263,222 at 0.047 lbs. ai/A applied alone." |
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