Ultraviolet light as sustainable Technology for Disease Control in vineyards: effects on grapevines, pathogens and potential applications. A review

The agri-food sector requires sustainable alternatives to chemical pesticides due to associated environmental risks and the continuous development of pathogen resistance. Supplemental ultraviolet (UV) light is a promising solution in viticulture, with several studies reporting promising results under commercial field conditions, but significant gaps remain in optimizing field application strategies. This review synthesizes the dual influence of UV light on grapevines: both as a potent elicitor of natural plant defense mechanisms and as a source of direct pathogen suppression. The UV perception mechanisms and the subsequent cellular signaling events that lead to the accumulation of key defense-related compounds, such as stilbenes and pathogenesis-related proteins, are discussed. These effects are highly dependent on dose, wavelength and application through a continuous light or flash. For the direct germicidal effect, understanding dose reciprocity, wavelength effect, and the enhanced efficacy by avoiding photorepair is crucial. While in vitro control of these pathogens is reported, translating laboratory results to field applications is not always linear. The varied observed results against key pathogens like Erysiphe necator (powdery mildew), Plasmopara viticola (downy mildew), and Botrytis cinerea (gray mold) are contextualized in light of the pathogens infection mechanism. Finally, broader ecological and sustainability implications are discussed, namely potential effects on arthropod fauna and on the quality of grapes and resulting wine. This review aims to provide a novel perspective on the application of UV light as a sustainable disease control strategy in vineyards, integrating the combined action of UV-induced plant defense responses with its direct germicidal effects.