The study evaluated the efficacy of Symbiotic Co-culture of Bacteria and Yeast (SCOBY), primarily Komagataeibacter rhaeticus and Brettanomyces bruxellensis as a biostimulant to enhance brinjal (Solanum melongena) growth and productivity. In India, ~90 % of cashew apples are discarded during cashew nut production. This study utilized SCOBY cultured in cashew apple waste as biostimulant foliar spray in a field experiment conducted in Semberi village, Cuddalore district (2023 - 2024), using the traditional Semberi brinjal variety in a Randomized Block Design (RBD) with three replications. Eight different foliar treatment combinations, involving cell-free extracts of SCOBY cultured in cashew apple juice were applied at 30, 45 and 60 Days After Transplanting (DAT). Growth and yield parameters were recorded throughout the season. Among the treatments, a 50:50 ratio of 1 % cashew apple juice-fermented SCOBY and 1 % Pink Pigmented Facultative Methylotrophs (PPFM) (T8) produced a significant amount of growth-promoting phytohormones, with 26.81 µg/mL of Indole-3-Acetic Acid (IAA) and 87.4 µg/mL of Gibberellic Acid (GA3), which enhanced root development, stem elongation and flowering in brinjal. T8-treated plants recorded a maximum height (163.02 cm), leaf area (88.27 cm²) and the highest chlorophyll content (35.90). These plants recorded earlier flowering (50 % flowering in 41 days), produced more flowers (47 flowers/ plant) and yielded more and larger fruits (14 fruits/ plant, with a length of 20 cm and girth of 7.1 cm), resulting in a maximum yield of 3.1 kg/ plant, compared to the control (1.8 kg/ plant). Additionally, nutrient uptake was higher in T8-treated plants (95.81 kg/ha N, 25.23 kg/ha P and 99.56 kg/ha K). Principal Component Analysis (PCA) confirmed a strong correlation between T8 treatment and improved yield parameters. This study highlights cashew apple juice-fermented SCOBY as a sustainable, eco-friendly biostimulant that enhances brinjal productivity, recycles agricultural waste and supports regenerative agriculture.
Jayalakshmi et al. (Mon,) studied this question.