EFFICACY OF FOUR HERBICIDES APPLIED WITH A ROPEWICK WIPER TO <em>ISCHAEMUM</em> <em>MAGNUM</em>

Abstract

Field studies were conducted to evaluate the effectiveness of glyphosate, imazapyr, glufosinate ammonium and paraquat dichloride
applied with rope-wick wiper for the control of the grass, Ischaemum magnum. Control of I. magnum increased with increasing rates of herbicide application. Excellent control was obtained at the rates from 0.4 a.i kg ha^-1 of imazapyr to 1.5 a.i kg ha^-1 for glyphosate. Control of this grass was unsatisfactory with both glufosinate ammonium and paraquat dichloride. Regrowth occurred at the first and
third week after treatment for paraquat dichloride and glufosinate ammonium respectively. Phytotoxic effects of herbicides on I. magnum were considerably improved by increasing the volume of application to 200 l ha^-1 and the number of passes during herbicide application. However, glyphosate and imazapyr could also be applied at 40 l ha^-1. This was evident by the excellent control of I. magnum at the final week of control assessment. Young plants were found to be more susceptible to herbicide treatments, probably due to better coverage and shorter distance for movement of herbicides.