Quality control of pneumatic spraying in tomato

Resumo

Tomato is a vegetable of great importance on the national scene. One of the problems of this culture is the great susceptibility to attack by pests and diseases. Thus, one of the most used practices is chemical control with phytosanitary products. The objective of this study was to evaluate the technical parameters of pneumatic spraying in tomato culture, through the study of the volumetric index and the population of spray droplets, aiming to reduce the spray volume, obtain the best efficiency and the social and environmental safety of the applications. The study of the droplet population was performed using water-sensitive paper labels. These labels were placed in the canopies of the tomato plants at three different heights and two positions. The sprays were made using a pneumatic backpack sprayer. After applying the syrup (dye + water), the water-sensitive paper labels were collected and subjected to the coverage and droplet density analyses by the computer program “CIR” version 1.5. The pneumatic sprayer proved to be efficient for the application of phytosanitary products in the tomato. The percentage of the target covered area ranged from 2.1 to 8.3% for volumetric indices as a function of thirds and positions, whereas the density of droplets ranged from 145.4 to 690.1 drops cm-2 for thirds and positions of the tomato plants evaluated. Finally, the volumetric index of 5 mL m-3, with a consequent spray volume of 50 L ha-1, met the parameters of a quality spray.