This research was undertaken to develop methods to evaluate the surface tension and foliar wetting of surfactant added in herbicide. It used three surfactants (Extravon, Aterbane and Silwet), five concentration of herbicide and eleven surfactant concentrations each. Surface tension and foliar wetting were evaluated by drops weight and sprayed drops with 0,48 .l of solution over Cyperus rotundus leaves. The surface tension was decreased glyphosate added. Silwet was the best of surfactants to reduction on surface tension and increased on foliar wetting.
Surfactant; Cyperus rotundus; herbicide; experimental method; technology applyed