Exploiting superhydrophobicity to protect the grapevine against biotic and abiotic stresses

The increasing frequency of drought and heat stress poses significant challenges to sustainable viticulture. This study evaluated the potential of SafeWax, a fatty acid-based formulation capable of forming a superhydrophobic coating on leaf surfaces, to improve grapevine physiological performance under water deficit conditions. SafeWax has previously demonstrated efficacy against several plant pathogens and may provide additional benefits by modifying leaf surface properties.

During the 2024 and 2025 growing seasons, potted Vitis vinifera cv. Sangiovese vines were subjected to two irrigation regimes corresponding to 100% and 50% of evapotranspiration replacement. In 2024, SafeWax was applied once to the entire canopy at two application volumes before the onset of stress. In 2025, the experiment was repeated with modified application timing while maintaining a single application volume. Stem water potential (Ψstem), leaf assimilation rate (A), transpiration (E), stomatal conductance (gsw), berry diameter, and leaf temperature (T) were monitored throughout both seasons.

Results from 2024 showed no significant differences between treated and untreated plants, indicating that SafeWax did not adversely affect gas exchange processes. In contrast, the 2025 trial revealed that SafeWax altered grapevine responses under water stress, as evidenced by significant interactions between treatment and water availability for assimilation rate, stomatal conductance, and leaf temperature. Under drought conditions, SafeWax temporarily reduced leaf temperature and contributed to maintaining higher photosynthetic efficiency over time, without affecting stem water potential compared with untreated controls.

Overall, the findings suggest that SafeWax can modulate the leaf microclimate and physiological responses of grapevines subjected to water stress, improving leaf functionality while maintaining the overall water status of the plant. These results highlight the potential of bio-inspired superhydrophobic coatings as a sustainable strategy to enhance crop resilience to increasing environmental stress associated with climate change.