Comparative Efficacy of UAVs (Unmanned Aerial Vehicles) and Ground-Based Bait Applications for Olive Fruit Fly (Bactrocera oleae) Control in Greek Olive Orchards

The use of unmanned aerial vehicles (UAVs) in agricultural pest management has emerged as a promising alternative to conventional methods, particularly in challenging terrains. This study assessed the effectiveness of UAV-based versus ground-based bait spraying for controlling the olive fruit fly Bactrocera oleae in four regions in Greece (Larisa, Zakynthos, Trifillia, and Crete) over a four-year period (2021–2024). In each region, three olive orchards were selected: one received UAV-based bait applications, one was treated using standard ground-based bait application, and the third served as an untreated control. UAV applications were conducted using the M6E hexacopter, while ground treatments followed conventional protocols. Infestation levels were evaluated through systematic fruit sampling, assessing both overall and active infestations. Climatic and orchard data were also recorded to interpret variability in treatment outcomes. Results showed that both UAV and ground treatments significantly reduced infestation compared to the control. Active infestation ranged from 14.2–22.5% in control-untreated plots, 4.6–7.8% in UAV plots, and 5.3–8.4% in ground-treated plots. A significant year × treatment interaction indicated variable efficacy across years, with clearer treatment effects in 2021–2022. UAV applications were as effective or superior to ground spraying, especially in hard-to-reach areas. These findings support the integration of UAVs into pest management programs as a sustainable and efficient alternative for olive fly control.