Nozzle and spray volume effects on chemical control of maize diseases

Abstract

The fungicide application in the maize crop is becoming frequent. In this process, the choice and the correct use of spray nozzles are essential for its success. This work aimed to evaluate the efficiency of different nozzles (twin flat fan, twin air induction flat fan, turbo flat fan and hollow cone) combined with different spray volumes (70; 100 and 130 L ha^-1) in the disease control of maize. Droplet deposition, 1000-grain weight and yield were evaluated. The early cycle hybrid Maximus was used and the fungicide pyraclostrobin+epoxiconazole was applied, in the dose of 0.75 L ha^-1, in the R1 phase, with 20% of corn tassel formation. A control (non-treated plot) was used for comparison. A randomized complete-block design in a factorial model 4 x 3 + 1 (four spray nozzles, three spray volumes and the control) with 4 replications was used. The results showed that the type of spray nozzle did not affect maize yield. The use of turbo flat fan spray nozzle, in the higher tested spray volumes (100 and 130 L ha^-1), provided greater values of spray deposition in maize canopy. The evaluated fungicide controlled the diseases, increasing maize yield, which was, on average, 16.3% greater than that obtained in the control.