The effects of some pre-emergence herbicides on broadleaf weeds in field beans (Phaseolus vulgaris l.) cv. Canadian wonder.

Abstract

Five pre-emergence herbicides at two and three rates alone and in mixtures were evaluated for broadleaf weed control in field beans, cultivar Canadian wonder. Better control of weeds was obtained during long rainy season of 1981 than short rainy season of 1980. High rates of herbicides used gave good weed control, although varying degree of injury on beans were noticed at early stages, but then recovered later in the season. Similar observations were recorded when mixtures were used. During the short rains (1980), four r: herbicides at higher rates proved more effective on controlling weeds. Ketolachlor (2-ethyl-6- methyl-N-2-methoxy-l-methyl-a-chloro-acetanilide) plus metobromuron (3-(4-promophenyl)-1-methoxy-lmethyl- urea) at 2.5kg a.i./ha (tank mix); metolachlor at 2.0kg a.i./ha alone, alachlor (2-chloro-2', 6'-diethyl-N-(methoxymethyl) acetanilide) at 2.0kg a.i./ha, and combination with linuron (3(3,4-dichlorophenyl)-1-1-methoxy-lmethyl urea) and meto1achlor (at 1.5 + 1.5kg a.i./ha)