BRILLIANT BLUE DYE REMOVAL IN FUNGICIDE SPRAYING

The method used for removal of brilliant blue dye may have an influence in interpreting the results of spraying deposition studies. The aim of this study was to assess the number of washings and water volumes for brilliant blue dye removal from soybean leaflets and glass slides in fungicide sprayings with and without adjuvants. A completely randomized experimental design was used in a 3 x 3 x 2 x 4 factorial scheme. The factors consisted of number of washings (1st, 2nd, and 3rd), water volume (15, 20, and 30 mL), target type (soybean leaflets and glass slides), and spray solutions (fungicide ProdutorBR((R)) 0.5 L ha(-1) without and with the adjuvants vegetable oil Agr'oleo((R)) 0.5% v v(-1), mineral oil Nimbus((R)) 0.5% v v(-1), and surfactant Silwet((R)) 0.04% v v(-1)). Sprayings were carried out by using the nozzle model TT110015 at a pressure of 300 kPa (medium droplets). After spraying, targets were washed and the amount of brilliant blue dye removed per target area was detected by spectrophotometry. Brilliant blue dye removal is higher in glass slide when compared to soybean leaflets. With a single washing, a higher difficulty in removing the brilliant blue dye was observed for fungicide with vegetable oil. Only the first washing and a water volume of 15 mL are insufficient for brilliant blue dye removal from soybean leaflets and glass slides.