Effects of Ecklonia maxima seaweed extract on the fruit, wine-quality and microbiota in Vitis vinifera L. cv. Cabernet Sauvignon

Biostimulants and biofertilisers are considered environmentally friendly alternatives to synthetic fertilisers, plant growth regulators and crop improvement products. Broadly, plant biostimulants are expected to improve nutrient use efficiency, tolerance to abiotic stress, quality traits and availability of nutrients in the soil or rhizosphere. While there has been increasing interest in the use and benefits of seaweed extracts in wine grape cultivation, limited research has been conducted on Ecklonia maxima (EM), a seaweed specie indigenous to South Africa. In this study EM seaweed extract (Kelpak (R)) was applied on Cabernet Sauvignon as a foliar spray in one season at three grapevine phenological stages: one week before flowering (E-L 18), berry set (E-L 27) and at veraison (E-L 35), on irrigated and non-irrigated vines. The effects on grapevine physiology, grape berry and wine metabolites and microbiota (leaf, berry and must) were evaluated. Grapevine physiology was not influenced by the applied treatments. Leaf area was positively influenced by the EM foliar applications which resulted in improved sugars and organic acids accumulation during ripening. Similar trends were observed in phenolics accumulation in the fruit during ripening. There were large differences in the bacterial and fungal communities on the leaf and berry surfaces from pea-size to harvest. Furthermore, Botrytis and Erysiphe grapevine pathogens were decreased in the leaves and berries (from veraison to harvest) with EM applications. Overall, our study suggests that the use of foliar EM products is beneficial in increasing grape and wine metabolites and the symbiotic microbiota during the ripening period and to ensure sustainable viticulture. (c) 2024 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.