An agroecological assessment of uncrewed aerial vehicle spraying in Greek viticulture

Spraying pesticides with uncrewed aerial vehicles (UAVs) in European viticulture is currently only allowed when there are no viable alternatives or if it provides environmental and human health benefits. Using Greece as a case study, this analysis investigated the agroecological performance of UAV spraying in comparison with land-based pesticide application. A multi-objective linear programming model assessed farmer preferences for spraying pesticides with ground equipment or a UAV. Farmers concerned with non-economic goals preferred UAV targeted pesticide application, while production-orientated farmers favoured ground spraying. Depending on disease pressure, UAV spraying generated annual savings of €278–377 ha ^-1 on a flat vineyard compared to a trailed vine sprayer and €367–538 ha ^-1 on a steep-slope vineyard compared to a backpack sprayer. However, the estimated costs of custom-hiring UAVs in Greece made UAV spraying less profitable except in conditions of simultaneous extreme labour scarcity and high disease pressure on the steep-slope vineyard. UAV aerial broadcast had an environmental impact comparable to ground spraying, but UAV spot-spraying mitigated ecotoxicological risks of pesticide use by 46–50 %. Both UAV spraying methods substantially reduced human exposure to pesticides. In current regulation, UAV aerial broadcast would only be allowed in steep-slope viticulture if seasonal labour was unavailable. UAV spot-spraying could be permitted on both vineyards, but it would be economically feasible if hiring fees were €43–49 ha ^-1. The study concludes with recommendations to promote UAV spraying adoption among European farmers thereby contributing to the EU objectives to halve pesticide use and risk while potentially resolving labour availability challenges on abandonment-prone vineyards.