Abstract
Three herbicide experiments were conducted at the Lajas Research and Development Center to evaluate asulam (methyl sulfanilycarbamate) alone or in combination with other postemergence herbicides from 1960 to 1982. In the first experiment with sugarcane cv. P.R. 1028, application of asulam at 3.25 kg/ha, preceded by an early postemergence application of metribuzin [(4- amino-6-dimethyl)-3-methylthio-1,2,4-trianzin-5 (4H)-one] at 4.48 kg/ha, controlled weeds best (83% after 15 weeks) for the highest yield (218.4 tons cane/ha or 31.1 tons sugar/ha). Asulam alone (2.80 and 3.74 kg ai./ha) applied 5 weeks after planting was inferior in total weed control (59% and 71%) and a lower yield was obtained (111.8 and 99.9 tons cane/ha or 13.0 and 12.1 tons sugar/ha, respectively). In the second experiment, with sugarcane cv. P.R. 980, postemergence application of asulam (3.74 kg ai./ha) gave better control of grasses (75%) when applied 4 weeks after planting than at 6 weeks (66%). Asulam sprayed either 4 or 6 weeks after planting was not phytotoxic to sugarcane. In the third experiment, also with sugarcane cv. P.R. 980, dicamba (2-Methyl-3,6-Dichloro-o-anisic acid) at 0.56 kg ai./ha and Weedmaster™3 (a mixture of 10.3% dicamba + 29.6% 2-4.D) at 2.34 and 4.68 L/ha gave excellent control of broadleaf weeds (84% to 90%). These results were similar to those from the treatment with 2,4-0 (86%) and two handweedings (89%). The yields obtained from herbicide treated plots (113.0 to 117.6 tons cane/ha) were inferior to those from hand-weeded check plots (160.1 tons cane/ha).