EXTERNAL FACTORS AFFECTING THE ELECTROSTATIC DEPOSITION OF CHARGED DROPLETS ON PLANT LEAVES Kemal AMAYA Ali BAYAT ABSTRACT Many studies indicated that charging the pesticide spray droplets with high levels of static electricity improves the droplet deposition on the upper and under surfaces of plant leaves. However, the successful application of electrostatic spraying in the agricultural field requires understanding the external factors negatively affecting the electrostatic deposition of charged droplets on plant targets. So, this study aimed to investigate the factors such as micro-climate conditions and plant morphologies affecting the droplets’ electric-charge levels during movement from the electrostatic nozzle until deposition on the plant targets. Also, the study investigated the effect of the plant-target properties on the electrostatic deposition of efficiently charged droplets on the surfaces of these plant leaves. According to the reviewed studies, the charge value of droplets seriously decreases during the movement from the electrostatic nozzle to the target plant. That can negatively affect the electrostatic deposition operation of charged pesticide spray on the plant leaves. Some studies attributed that to the electric fields of the earth's atmosphere and the naturally occurring free charges that cause the ionization of charged pesticide droplets. Other studies indicated that evaporation causes charged droplets to consecutive split into smaller ones until losing whole their mass with the associated electric charge. Therefore, they are responsible for the decrease in the charge-to-mass ratio when the charged droplets move from the electrostatic nozzle to the target. Regarding the effect of the plant targets’ properties, some research indicated that the location of the target leaf inside the plant can also affect the electrostatic deposition since the charged droplets are attracted to nearby earthed targets. The electrostatic-spraying techniques can be successfully used at least on the cotton plant without regard to the severity of leaf wilt or drought stress during dry seasons that affect the plant conductivity. However, the point edges of some types of plant leaves can cause Gaseous-discharge currents between them and the highly charged spray cloud that can negatively affect the electrostatic deposition. Keywords: Electrostatic spraying; Plant morphologies, Evaporation, Droplet deposition, Induction charging method. INTERNATIONAL PARIS CONGRESS ON APPLIED SCIENCES April 1-3, 2023 - Paris 266 Çukurova University, Faculty of Agriculture, Department of Agricultural Machinery and Technologies Engineering, Adana, Türkiye ORCID: 0000-0002-5096-1585 Çukurova University, Faculty of Agriculture, Department of Agricultural Machinery and Technologies Engineering, Adana, Türkiye ORCID: 0000-0002-7104-9544