Surface tension and area of spreading of solutions with herbicide and adjuvant in leaves of Conyza canadensis

Abstract

This study aimed at evaluating the surface tension and the area of drop spreading on leaves of horseweed (Conyza canadensis) solutions of glyphosate and 2.4-D with adjuvant. The experimental design was completely randomized with four replications. The treatments consisted of solutions of glyphosate (960 g ha^-1) and 2.4-D (720 g ha^-1) isolated and also in combination, plus the addition of Energic® adjuvant and Joint Oil ® at concentrations of: 0, 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0% (v v^-1). We concluded that the Energic ® was more effective in reducing the surface tension of the solutions than in promoting the drop spreading on the faces of leaf C. canadensis. Whereas, the Joint Oil® was more effective in reducing the surface tension of the mixture of glyphosate + 2.4-D, than when using herbicides isolated. The efficiency of the Joint Oil® drops spreading on the faces of the leaf C. canadensis was dependent on the concentration of the adjuvant and the herbicide.