Optimization, Characterization, & In vitro Evaluation of Spent Mushroom-Based Bio-fungicide for Tomato (Solanum lycopersicon L.) Disease Management

Aims: This study evaluated the potential of spent mushroom substrate (SMS) as an organic bio-fungicide for managing tomato diseases effectively while promoting sustainable agricultural practices. Study Design: Optimization tests utilized ANOVA (p < 0.05) to assess the effects of fermentation periods and SMS-to-water ratios on the bio-fungicide's effectiveness. Significant differences among treatments were analyzed using LSD, identifying optimal preparation conditions. A T-test compared the physico-chemical properties of fermented and non-fermented SMS-based bio-fungicides. Additionally, In vitro efficacy against various fungal diseases of tomato was evaluated using ANOVA and Tukey’s HSD test for precise treatment comparisons. Place and Duration of Study: The study was conducted at the Mushroom and Crop Protection Laboratory, Surigao del Norte State University (SNSU) – Mainit Campus, Magpayang, Mainit, Surigao del Norte, Philippines. Methodology: Fermentation periods (2, 4, and 7 days) and SMS-to-water ratios (0.5 kg, 1.0 kg, and 2.0 kg per 20 L) were evaluated to optimize beneficial microbial growth. Physico-chemical properties of both fermented and non-fermented SMS-based bio-fungicides were analyzed to determine nutrient composition and microbial activity. In vitro efficacy trials assessed the bio-fungicide’s ability to control soil-borne, foliar, and post-harvest tomato diseases. Results: ANOVA and LSD analyses identified 1.0 kg SMS per 20 L water fermented for 7 days as the optimal formulation, achieving the highest microbial population (41,666.67 CFU/mL) dominated by Trichoderma spp., Penicillium spp., actinomycetes, and Bacillus spp. Fermentation significantly enhanced the nutrient profile, increasing levels of P, Ca, Mg, Fe, and Cu, while reducing N, Zn, and Mn, thereby optimizing microbial activity and nutrient availability. In vitro assays demonstrated superior efficacy of fermented SMS bio-fungicides at 20 mL/100 mL water in managing tomato diseases, significantly outperforming non-fermented formulations. Conclusion: This study highlights SMS as a sustainable and eco-friendly bio-fungicide, aligning with circular economy principles in mushroom production. Its effectiveness in controlling tomato diseases underscores its potential as an innovative solution for sustainable agriculture. Further field validation and application to other crops are recommended to maximize its broader utility.