Influence of glyphosate and paraquat pre-transplant treatments on weed control and peppers yields

Abstract

Two field experiments, both with Cubanelle and Yollow Wonder peppers (Capsicum annuum L.), were conducted at the Juana Díaz Research and Development Center in 1981-82. Weeds were induced to grow through periodic irrigations for 16 days before peppers were transplanted. Either glyphosate or paraquat at 1.12 kg ai/ha were then applied to control emerging weeds in two separate experimental areas 5 days before setting out transplants. Oxyfluorfen at 1.12 kg ai/ha applied 2 days before transplanting peppers caused the highest phytotoxicity (significant at P=0.05) as recorded during 14, 28 and 42 days after treatment in both experiments. Neither alachlor (1.68 kg ai/ha), oxadiazon, trifluralin nor pendimethalin applied 2 days before transplanting at 1.12 kg ai/ha was phytotoxic to peppers. There were no significant differences in Cubanelle or Yollow Wonder pepper yields among herbicide treatments and handweeded check. The highest pepper yields (47,771 and 44,964 kg/ha) were obtained in plots treated initially with glyphosate and later by either paraquat directed postemergence spray or oxadiazon pre-transplant at 1.12 kg ai/ha each, respectively. In the other experiment, hand-weeded check and preplant application of paraquat at 1.12 followed by oxyfluorfen at 1.12 kg ai/ha were the highest yielders with 47,771 and 44, 964 kg/ha, respectively.