Effect of conventional versus electrostatic spraying of calcium-containing formulations to apples

Abstract

Surface application of calcium fertilisers to apples is a widely used and recommended strategy to prevent the development of bitter pit, a calcium-related disorder that can lead to major economic losses. Air-assisted electrostatic sprayers (ES) produce spray droplets which are 900 times smaller than those supplied by conventional sprayers. These tiny droplets are carried deep into the plant canopy in a high-speed air-stream. Such spraying method may increase more than twice the deposition efficiency of treatments as compared to non-electrostatic sprayers. However, the significantly smaller size of the drops produced by ES may prove critical for the application of treatments under the prevailing dry Summer conditions in Southern Europe, due to the potential rapid evaporation of the solutions applied to the plants.