Study on the precision mechanism for droplet application and target range in tropical fruit trees, by unmanned aerial spraying systems

• Grant number: 25/18601-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Marcelo da Costa Ferreira
• Grantee: Rafael Davanzo Ballera
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 24/15469-9 - Study on the Mechanism of Droplet Precision Delivery and Target Matching in Tropical Fruit Trees by Unmanned Aerial Spraying Systems, AP.PFPMCG.R

Abstract

The commercial use of drones in agriculture, with multiple rotors and movable wings, began around 2010, with official regulation in Brazil occurring in 2017. Since their introduction, demand for their use has grown, with natural concerns about their efficiency and safety. In the case of drones for the application of phytosanitary products, efficiency considers both the expected effects and safety. In this context, there are marked differences in the use of drones, which relate to their payload capacity, agility, height, and application speed, the dynamics of droplet distribution based on the airflow provided by the propellers, the absence (so far) of agitation of the spray solution inside the tank, and the reduced application volume. These characteristics have generated some uncertainty in adopting the technique due to the uncertainty that the expected results will be achieved. This is also due to the limited research conducted on the technique, which is relatively recent, especially compared to other application techniques, and even due to its widespread use, without considering the technique's key positioning capabilities. In traditional applications, there are situations where efficiency and safety can result in damage due to drift and runoff. The possibility of localized applications with drones, complementing other techniques, can provide a good justification for adoption. In this context, the objective of this research is to evaluate general aspects of phytosanitary product application with drones on fruit trees, coffee, and lychee. This study evaluates highly concentrated sprays used for application with very low spray volumes (pH, electrical conductivity, viscosity, surface tension), as well as direct evaluations on canephora and arabica coffee crops (Espírito Santo and São Paulo) and lychee (São Paulo). The work will include a stage conducted by partners in China, where machine learning assessments will be conducted to achieve more accurate and precise applications on plants, increasing the proportion of spray that reaches the target and avoiding losses due to drift. This is expected to expand knowledge about remotely piloted aircraft, which are promising for efficient and safe phytosanitary treatment. (AU)