The experiment was carried out to evaluate the leaf deposition and the efficiency of different drop pattern by spraying cotton plants at the end of the growing season, under adverse air temperature and humidity conditions. The sprays, applied at the same pressure, were made with a JACTO UNIPORT speed-sprayer equipped with the nozzles JA3 (hollow cone), AD-IA/D 11003 (double flat fan), and AD-IA 11003 (flat fan) for 150 L ha-1 spray volume, and the nozzle AD-IA 11004 (flat fan) for 200 L ha-1 spray volume. It was applied the FD&C Brue n.1 tracer at 0.179% in the spraying solution to determine the volume of spray deposition on leaf samples obtained from the upper, the middle, and the lower third of the plants canopy. The leaf samples were washed with 20 ml of deionized water. The recovered volumes were analyzed by spectrophotometry. The data were submitted to the Gompertz model regression analysis for treatments comparison. The nozzle AD-IA 11003 gave the highest leaf deposit in all plant parts. The application efficiency was 27.45; 35.08; 47.60 and 39.25% for the nozzles JA3, AD-IA/D 11003, AD-IA 11003, and AD-IA 11004, respectively.
tracers; leaf deposition; cotton
