The aim of this research was to study leaf pH and to evaluate the spreading area after application of solution surfactants on the following aquatic weeds: Brachiaria mutica, Brachiaria subquadripara and Panicum repens. Aquatic weeds were cultivated in reservoirs containing water under field conditions with foliar tissues collected when plants reached their full development (before flowering). Leaf pH medium values varied between 5.71 and 6.03, with B. mutica standing out with the highest pH values (5.72 and 6.03 for the upper and lower surfaces, respectively). Surface tension of droplets for glyphosate alone (5.0% v v-1), glyphosate + Aterbane BR (5.0% + 0.5% v v-1), glyphosate + silwett L-77 (5.0% + 0.05% v v-1), and surfactants alone, Aterbane BR (0.5% v v-1) and Silwet L-77 (0.05% v v-1) was, respectively, 72.1; 28.7; 23.3; 37.3 and 22.1mN m-1. B. subquadripara obtained the highest spreading area for the upper and lower leaf surfaces.
aquatic weeds; glyphosate; leaf pH; surfactants and spreading
