Spray nozzle effect on soybean rust chemical controlAbstract
Soybean rust chemical control depends on the correct selection of the spray nozzles. This study evaluated the spray nozzle effect on soybean rust control application. A randomized complete-block design with four replications was used, in a factorial model (4 x 2) + 1: four spray nozzles (hollow cone spray nozzles, with and without air induction, pre-orifice twin flat fan and turbo twin flat fan), two spray volumes (150 and 200 L ha-1) and the control (non-treated plot). M-SOY 8008 soybean (early cycle) was sown. After the application of the fungicide tebuconazole, with the different nozzles and volume rates, the spray deposition on the plant canopy, rust severity, defoliation level and yield were evaluated. The results showed that there was no influence of the nozzle type neither of the application volume in rust control. In the canopy lower part, the coverage obtained with the four nozzles was less than 7% of the area, therefore, it is necessary to find strategies to increase that deposition. The fungicide decreased rust severity, increasing soybean yield, which was, on average, 157% greater than that obtained in the control.
application technology; Glycine max L.; Phakopsora pachyrhizi
