Deposição e eficácia da aplicação de calda herbicida com aeronave remotamente pilotada em função de taxas de aplicação e classes de gotas

Abstract

Brazilian agriculture stands out on the global stage for its high productivity and increasing adoption of sustainable technologies. In this context, remotely piloted aircraft (RPAs) have emerged as a rapidly adopted technological innovation for the application of pesticides. However, several technical questions challenge farmers and professionals when it comes to herbicide application. This study aimed to evaluate the effects of application rate (10, 20, and 150 L ha⁻¹) and droplet size (medium and coarse) on the weed control efficacy of glyphosate + carfentrazone-ethyl applied using RPA equipped with rotary atomizers and a backpack sprayer. To this end, two field experiments were conducted in an area with high infestation of Ipomoea triloba, Alternanthera tenella, and Commelina benghalensis. Spray quality was characterized by evaluating the volumetric median diameter (VMD), relative span (RS), potential drift risk (PDR), droplet density (droplets cm-2), coverage (%), and deposition (µg cm-2). Weed control efficacy was determined by assigning field scores (3, 7, 14, 21, and 28 DAA). The results indicate that rotary atomizers produced droplets in the “Fine” and “Medium” classes. The application rate of 10 L ha-1 was equal to the rate of 20 L ha-1 in most evaluations, especially in Experiment 2. Applications with RPA (10 and 20 L ha-1) produced a VMD lower than 205,41 μm, while hydraulic nozzles (GRD 120015 and ULD 120015), used in ground applications (150 L ha-1), produced a VMD greater than 484,59 μm. In general, both application methods resulted in similar RA and droplet density. Aerial applications showed higher PDR (>24,94%) compared to ground applications (<1,66%). Ground applications (>23,52%) promoted higher coverage than aerial applications (<3,58%). Despite lower coverage, RPA promoted depositions similar to ground applications. In conclusion, RPA applications promoted high levels of control (> 90%), comparable to ground applications.