Background/Introduction: Botrytis cinerea Pers. is a devastating fungal pathogen affecting numerous crops, with particular significance in viticulture as the causative agent of grey rot. Under favorable climatic conditions, B. cinerea can cause 30-40% fruit losses, representing a major challenge for the wine industry. While chemical fungicides remain the primary control method, increasing pathogen resistance, concerns about human health and environmental impacts, and market demands for residue-free products necessitate alternative control strategies. Biorational products, particularly plant-derived antifungal compounds, show promise as fungal inhibitors, but their field application faces challenges including compound lability, poor solubility, and lack of specificity. Nanoencapsulation technology offers a solution to maximize biorational efficacy through improved delivery and stability.

Goals: This study aimed to develop and validate chitosan oligomer-based nanocarriers for the delivery of biorational antifungal compounds from Dyer's madder (Rubia tinctorum L.) and cat's claw (Uncaria tomentosa (Willd. ex Schult.) DC.) extracts for B. cinerea control in vineyards.

Methodology: This research combined laboratory and field approaches. System stability, the protection of bioactive compounds, and controlled release mechanisms were evaluated under laboratory conditions. Minimum inhibitory concentrations (MICs) were determined against B. cinerea. Field trials were conducted at D.O.P. Ribera de Duero (Bodega Dominio Fournier, González-Byass group), using commercial chitosan as a control, to assess effectiveness, phytotoxicity, and compatibility with vineyard management practices.

Results: The laboratory assays revealed significant pathogen inhibition with MICs ranging from 250 to 375 μg/mL, while maintaining the bioactive properties of the encapsulated compounds. The field trials demonstrated the high effectiveness of the nano-delivery systems, showing disease incidence rates of 18–35% depending on the encapsulated bioactive compound, compared to 85% in untreated controls and 37% with commercial chitosan. No phytotoxicity symptoms were observed. The treatment integrated well with current vineyard management practices and did not affect wine organoleptic properties.

Conclusions: The developed nano-delivery systems offer a viable, eco-friendly tool for sustainable viticulture, effectively controlling B. cinerea while maintaining wine quality. This approach presents new perspectives for sustainable disease management in high-value wine production.

Funding: This research was funded by the Junta de Castilla y León under project VA148P23, co-financed by the European Regional Development Fund.