BIOASSAY OF SOME PRE-EMERGENCE HERBICIDES IN MUSTARD-POLYGONUM ASSOCIATON UNDER TERAI AGRO-CLIMATIC SITUATION

Abstract

In mustard varieties pendimethalin doses of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 1.0, 1.2 and 1.4, kg a.i./ha and fluchloralin doses of 0, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2 and 2.4, kg a.i./ha were used in the field experiment having a plot size of 1sq m area. In Polygonum sp pendimethalin doses of 0.0, 0.05, 0.10, 0.15, 0.2,0.25, 0.3, 0.35, 0.4, 0.45 and 0.5, kg a.i./ha and fluhloralin doses of 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.60, 0.7, 0.8, 1.0 and 1.2, kg a.i./ha were used.Among the herbicides fluchloralin had wide range of selectivity and can be applied safely inB9 and chaiti for controlling Polygonum. However, jhumka became highly sensitive topendimethalin and less tolerant to fluchloralin resulted in non-selective action of pendimethalin and narrow range of selectivity in fluchloralin for controlling Polygonum.