ABSTRACT: Spraying of crop protection products can be affected by weather conditions and spray nozzles, altering deposition patterns and coverage of the target surface. The objective of this research was to analyze the quality of sprayings performed in three periods of the day (9:00 am, 2:00 pm, and 6:00 pm), using two different droplet sizes (fine and coarse) in soybeans. Coverage and deposition were evaluated in the upper, middle, and lower portion of soybean canopy. Spraying the products at 2:00 pm increased leaf coverage in the medium portion but also increased losses to the soil. Spray nozzles with fine droplet sizes provided greater coverage and deposition in the medium and upper portion of the crop for the sprayings performed in the morning. If compared to coarse droplets, fine droplets increased leaf coverage and had no interference with the losses to the soil.

ABSTRACT 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 × 3 × 2 × 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® 0.5 L ha−1 without and with the adjuvants vegetable oil Agr’óleo® 0.5% v v−1, mineral oil Nimbus® 0.5% v v−1, and surfactant Silwet® 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.

ABSTRACT The high susceptibility to diseases of fine table grapes cultivars demand intensive use of pesticides, and the presence of water on the leaf surface can worsen the deposition of these products. The objective of this study was to evaluate the spray deposition in vine leaves in different conditions of leaf wetness, and test the effectiveness of an artificial ventilation method to remove water on the leaf surface. We evaluated the spray deposition in vine applied over: wet canopy (presence of high leaf wetness); canopy dried artificially (dried with air jet from air-assisted sprayer, wind speed of 25 km h−1) and canopy dried naturally (naturally dried leaves and free of water on its surface). Saline marker was used in the spray and the deposition on the canopy was determined by conductimetry. A pesticide application in vine, with the presence of water in the leaf surface, causes losses by run-off and reduces the deposit of spraying. The use of air jet formed by air-assisted sprayer fan is efficient for the removal of water on the vine leaf surface and its use can increase the favorable period for the application of pesticides without causing dilution and losses by run-off of the applied product.