Effect of Application Techniques on Spray Quality Optimization in Sweet Pepper Cultivation in Protected Environments

Air assistance and electrical charge transfer to droplets can optimize pesticide applications and reduce losses in sweet pepper cultivation. The objective of this study was to evaluate the effects of spray rate and pneumatic spraying with and without an electrostatic charge on spray deposition, spray coverage, and ground losses in sweet pepper crops. Four application techniques were employed: standard farmer hydraulics (SFH), reduced volume hydraulics (RVH), pneumatic with air and electrostatic assistance (PAEA), and pneumatic with air assistance (PAA). The effects of the application techniques on spray deposition varied as a function of plant height, canopy depth, and leaf surface. The SFH resulted in the greatest amounts of spray deposition on the adaxial leaf surface. In contrast, PAEA resulted in the greatest amounts of deposition on the abaxial leaves. The PAEA treatment improved spray coverage on abaxial leaves of the external canopy but did not improve spray coverage on the internal canopy. Compared to the SFH treatment, the 50% reduction in the spray rate of the RVH treatment decreased deposition and spray coverage. The pneumatic treatments, regardless of electrostatic charges, resulted in lower spray loss to the ground.