Phytotoxic Effect of Herbicides with and without Surfactant on Weed Growth and Yield of Wheat

Abstract

Use of surfactants is an effective mean of improving herbicide efficiency. The herbicides methabenzthiazuron [l ,3-Dimethyl-3-(2-benzothiazolyl)urea], chlortoluron[N-(3, Chloro-4-methyl phenyl)-N-N-dimethyl urea] + MCPA(2-Methyl-4-chlorophenoxy acetic acid] and lsoproturon [3-(4-isopropylphenyl)-1, 1-dimethyl urea] were evaluated for weed control at recommended rates of 1.26, 1.50 and 0.97 a.i. kg ha-1, respectively, in comparison with a 12.5 and 25% less rate after the addition of 0.2 % surfactant. Application of herbicides with surfactant even at lower rates was as effective as recommended rates in controlling weeds and increasing grain yield. Grain yield ranged from 20.8 to 45.3 % and 26.3 to 38.1 % more than the weedy check in 1992-93 and 1993-94, respectively, for various herbicide concentrations. Thus for economical weed control, a lower rate of herbicide with the addition of surfactant should be recommended.