Study on pesticide utilization efficiency, droplet deposition and residues sprayed by UAV in processing pepper field.

BACKGROUND: Plant protection unmanned aerial vehicle (UAV) spraying has emerged as a core precision pesticide application technology, but systematic field evidence regarding its comprehensive application performance, pesticide residue dissipation and dietary safety risks in processing pepper production remains insufficient, restricting its standardized popularization. This study aimed to clarify the field applicability of UAV spraying by comparatively evaluating pesticide utilization efficiency, droplet deposition distribution, residue dissipation dynamics and dietary risk profiles of three commonly used pesticides (chlorantraniliprole, afidopyropen and fluazinam) in processing pepper fields, with boom sprayer and knapsack sprayer treatments set as conventional control groups. RESULTS: Field trials conducted in Shihezi (Xinjiang) from 2023 to 2025 demonstrated that UAV spraying achieved consistently higher pesticide utilization efficiency (3.09-84.60%) throughout the whole growth period relative to boom spraying (1.45-73.62%). All treatments exhibited a distinct vertical droplet deposition gradient of upper > middle > lower canopy in pepper plants. The three tested pesticides showed the shortest dissipation half-lives (3.74-4.69 days) under UAV application. Terminal pesticide residues at harvest did not differ significantly among the three application methods. Both chronic dietary risk (%ADI < 0.2%) and acute dietary risk (%ARfD <1.0%) for all treatments were substantially below official safety thresholds. CONCLUSION: UAV precision spraying improves pesticide utilization efficiency and reduces effective pesticide dosage without elevating dietary residue risks in processing pepper production. This technology resolves the low-efficiency pain points of traditional spraying methods, provides robust field validation for the safety and superiority of UAV-based plant protection, and offers a practical technical support for low-input, high-efficiency precision management in sustainable processing pepper cultivation. © 2026 Society of Chemical Industry.