Herbicide Screening Trials on Yams (Dioscorea sp.)

Abstract

Two field trials were conducted during 1979-1980 on a Corozal clay (Ultisol) and a Coto clay (Oxisol) to screen promising herbicides for weed control on yams. In one experiment, Ametryn at 2.24, 4.48 and 8.96 kg/ha, Nitrofen at 6.72, 13.44 and 26.88 kg/ha, Paraquat at 2.34, 4.68 and 9.36 l/ha and Prometryn at 2.24, 4.48 and 8.96 kg/ha were tested. In another experiment, Ametryn at 2.24, 4.48 and 8.96 kg/ha, Cryanazine at 4.48, 8.96 and 17.92 kg/ha, Diphenamid at 11 .2, 22.4 and 44.8 kg/ha and Trifluralin at 2.34, 4.68 and 9.36 l/ha were applied. Ametryn or Prometryn at 4.48 kg/ha rate or Nitrofen at 6.72 kg/ha gave good preemergence weed control in one experiment. Paraquat applied postemergently gave best weed control performance of the four herbicides tested. Cyanazine at 4.48 kg/ha was ineffective at lower rates but the same herbicide at the medium rate of 8.96 kg/ha or above gave as good weed control as Ametryn at 4.48 or 8.96 kg/ha in experiment 2. Diphenamid and Trifluralin were ineffective against broadleaf weed species at their recommended rates of application.