Effect of four herbicides on establishment and forage yield of Guinea grass in Puerto Rico

Abstract

A field experiment was conducted at the Gurabo substation to evaluate atrazine, simazine, diuron and tebuthiuron for pre-emergence control of weeds in a Guinea grass pasture. Tebuthiuron at 3.36 kg a¡/ha was the most effective herbicide in controlling weeds, but was also very phytotoxic to the pasture even at a lower rate. The remaining herbicides provided satisfactory weed control and were not as phytotoxic to Guinea grass. There were no significant yield differences among herbicide-treated plots except for the plot with diuron. Diuron-treated plots at 3.36 kg ai/ha outyielded those with other herbicide treatments and the weeded check, but no significant statistical differences in yield were observed among plots with diuron at 3.36 kg ai/ha atrazine at 4.48 kg ai/ha and the handweeded check.