Revista Brasileira De Herbicidas 2014; 13(3): 225-234
Distribution, droplet diameter and phytotoxicity of herbicides applied in eucalyptus seedlings with air induction nozzles
The spray nozzles are responsible for the formation of droplets, each nozzle type exerts a different function, with its own characteristics related to the deposition of droplets according to the desired target. This study aimed to evaluate the distribution, droplet diameter and phytotoxicity of glyphosate and isoxaflutole herbicides applied in eucalyptus seedlings with air induction nozzles (AIUB 04 and TTI 110 04). The spectrum of droplet diameter was determined by particle size analyzer by laser light diffraction. The volumetric distribution was evaluated in deposition table to collect the sprayed volume. The visual assessments of phytotoxicity of the herbicides were carried out at 7, 14, 21, and 28 days after application. At the end of the experiment it was determined the dry mass of stem and leaves. The TTI 110 04 nozzle had greater volumetric median diameter (VMD), lower percentage of droplets smaller than 100 µm and lower uniformity coefficient of drops compared to the AIUB 04 nozzle. For the spray nozzle model TTI 110 04, the spacings of 0.45 and 0.75 cm showed better uniformity (variation coefficient lower than 10%). The model AIUB 04 resulted in no acceptable coefficient of variation. The application of glyphosate with the AIUB 04 nozzle increased phytotoxicity. The herbicide isoxaflutole was shown to be selective to eucalyptus.
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