Application techniques of pesticides in greenhouse tomato crops

Resumo

Due to the lack of information on application technology in horticulture, the aim of this research was to evaluate the effect of three application techniques on different parts of the canopy of tomato cultivated in greenhouse. The application techniques evaluated were: Technique 1 – Spray gun with two hollow cone nozzles, model JA-2 (700 kPa), application rate of 618 L ha^-1; Technique 2 - Vertical boom spray equipped with six nozzles, model ATR 0.5 (700 kPa), application rate of 493 L ha^-1; Technique 3: Vertical boom spray with six standard flat fan nozzles, model AXI 11002 (400 kPa), application rate of 1442 L ha^-1. The relative deposition and the coverage of the tomato leaves of the tomato at the internal and external collection positions of the plants, in three strata (upper, middle and lower) of the tomato canopy were evaluated as indicators of application quality. In the lower and middle strata of the canopy, the deposition on the inside of the plants was 21 % and 34%, respectively, lower than in the outside. On average, the coverage is 2.5 times smaller on the adaxial surface in relation to the abaxial surface. In general, the technique of application Spray gun JA-2 (618 L ha^-1), used in commercial farming, provides better quality of the application. However, all the application techniques evaluated need to be optimized in order to provide better distribution of the spray, mainly in the critical regions, such on the inside of the plants in the lower and middle canopy stratum and the abaxial surface of the leaves.