An efficient application of phytosanitary products depends, among other factors, on a good selection of nozzles and the application volume rate of the solution used. Thus, the objective of this work was to evaluate the efficiency of different models of hydraulic tips and application volume rates on spray coverage on targets positioned in the upper, middle and lower thirds of corn plants. The application volume rates evaluated were: 50 l · ha ⁻¹; 100 l · ha ⁻¹; 150 l · ha ⁻¹; 200 l · ha ⁻¹; 300 l · ha ⁻¹ and 400 l · ha ⁻¹. The following nozzles were used: TT 11001, TTJ60 11002, TXA 8003, 30HCX 12, GRD120 02 and GAT11002. Applications were carried out in phenological stages V6–V7 of corn plants. There was a directly proportional relationship between an increase in application volume rate and the levels of spray coverage and droplet density in the three thirds of corn plants. The application volume rate evaluated, except for 50 l · ha ⁻¹ in the lower third, provided a number of droplets compatible with the literature recommendations for the application of systemic fungicides. All tips evaluated provided a number of droplets compatible with the recommendations in the literature for the application of systemic fungicides, therefore, they can be recommended for use in spraying on corn crops.

The study was conducted at the University of Nebraska Pesticide Application and Technology Laboratory in North Platte, Nebraska in July 2015. Two application volume rates (100 and 200 l · ha−1) and three nozzle types (XR, AIXR, TTI) were selected at two flow rates (0.8 and 1.6 l · min−1) and at a single application speed of 7.7 km · h−1. Each collector type [Mylar washed (MW), Mylar image analysis (MIA), water-sensitive paper (WSP), and Kromekote (KK)] was arranged in a randomized complete block design. Each nozzle treatment was replicated twice, providing six cards of each collector type for each nozzle treatment. A water + 0.4% v/v Rhodamine WT spray solution was applied, given the fluorescent and visible qualities of Rhodamine, which allows it to be applied over all the collector types. MW had the highest coverage at 18.3% across nozzle type, followed by WSP at 18%, KK at 12% and lastly by MIA at 4%. MW resulted in a 58% increase in coverage, WSP in a 56% increase, and KK only an increase of 39% when the volume rate was doubled from 100 l · ha−1 to 200 l · ha−1 across nozzle type. MW coverage was similar to KK for half of the nozzles (XR 11002, XR 11004, AIXR 11002). Droplet number density fixed effects were all significant for nozzle type and collector type (p < 0.001) as was the interaction of nozzle type and collector type (p < 0.001). Results from this study suggest a strong correlation to data produced with WSP and MW collectors, as there was full agreement between both types except for the TTI 11004. Using both collector types in the same study would allow for a visual understanding of the distribution of the spray, while also giving an idea of the concentration of that distribution.