Abstract
Oxyfluorfen [2- chloro-1- (3-ethoxy-4-nitraphenoxy)-4-(trifluoromethyl) benzene] was evaluated throughout a series of experiments carried out from 1983 to 1986 at the Lajas Research and Development Center. In 1983 preemergence oxyfluorfen at 1.68, 3.36 and 6.72 kg ai/ha reduced significantly (P=0.05) the germination and plant height of pigeon pea cv. 2,B-Bushy. Preemergence oxyfluorfen at 1.32 kg ai/ha reduced germination of cv. Kaki by 20% in 1984-85, and by 5% in 1985-86. Oxyfluorfen at 0.33 and 0.66 kg ai/ha was found to be safe for germination of pigeon pea. There was severe injury from postemergence treatment to top of weeds and crop at 0.33 and 0.66 kg ai/ha. Phytotoxicity symptoms of pigeon pea disappeared after 9 weeks in all treated plots. The number of grass weeds was significantly reduced by Preemergence oxyfluorfen even with the 0.33 kg ai/ha rate and two direct applications of 0.25 kg ai/ha rate in both years. Broadleaf weeds were more effectively controlled by oxyfluorfen at 0.66 kg ai/ha applied over the top, followed by a direct application at 0.25 kg ai/ha. In 1984-85, the highest yield of pigeon pea (7,989 kg/ha) was obtained with oxyfluorfen at 0.33 kg ai/ha applied over-the-top plus the same herbicide at 0.25 kg ai/ha as post-directed spray. Pigeon pea yield with preemergence treatment of oxyfluorfen at 0.33 kg ai/ha plus two post-directed applications at 0.25 kg ai/ha ranked second, with 7,826 kg/ ha. There were nonsignificant differences (P = 0.05) in pigeon pea yields among oxyfluorfen treated plots, hand-weeded and non-weeded plots in 1985-86. Yields ranged from 6,470 kg/ha in hand-weeded plots to 4,428 kg/ha in non-weeded plots.