Efeito de adjuvantes em soluções com fungicida na tensão superficial e na área de molhamento de gotas depositadas nas faces foliares da soja

The aim of this study was to investigate the effect of concentrations of nonionic adjuvant and mineral oil in the spray volume of fungicide, in superficial tension and wetting area of drops deposited on soybean leaves. Two experiments were performed under completely randomized 6x2 factorial design, with seven replicates. For the first experiment Energic® was used as the nonionic adjuvant, and for the second one, mineral oil Joint Oil ® . For both cases, the primary factor concerns the concentrations of the surfactant (0.00, 0.05, 0.10, 0.15, 0.20 and, 0.25% (v v -1 ) of Energic ® ; 0.00, 0.25, 0.50, 0.75, 1.00 and 1.25% (v v -1 ) of Joint Oil ® ), and the second factor, the spray volume with and without use of fungicide. We deposited drops (15 µL) on the adaxial and abaxial surface leaves of soybean cv. BMX Forca RR. It was concluded that the lower surface tension of spray volume of fungicide were obtained in concentrations up 0.1% and 0.5% to nonionic adjuvant and mineral oil, respectively. The concentrations of 0.2% and 0.75% of nonionic adjuvant and mineral oil, respectively, resulted in larger areas of wetting on soybean surface leaves.