Abstract
BACKGROUND: Sclerotium rolfsii is a devastating soil borne pathogen causing collar rot in chickpea, leading to significant crop yield losses. Sustainable diseases management strategies are required to reduce dependence on chemical fungicides and mitigate environmental hazards risks. Biochar, a carbon-rich soil amendment, improves soil health and enhances soil microbial activity, aiding in soil borne disease suppression. Cassia fistula, known for its bioactive compounds, exhibits antifungal properties that can prevent S. rolfsii. Additionally, Trichoderma harzianum, is effective biocontrol agent, promotes plant growth and disease suppression; thus, making the integrated use of these components a promising approach for controlling of S. rolfsii in chickpea cultivation. METHOD: Chickpea plants were treated with 3% Rice husk biochar (RHB), 450 ppm Cassia fistula extract, and Trichoderma to assess their effectiveness against Sclerotium rolfsii. The study analyzed biochar properties (C, H, N, P, ash content, cation exchange capacity and surface area) and treatment impacts on T. harzianum spore counts (CFU/mL), plant growth (root mass and shoot length), soil health (microbial population), disease incidence (%), and phenolic content in field conditions. RESULTS: Key findings indicated that 3% RHB (52.3% carbon, pH 8.2) with 450 ppm cassia extract significantly enhanced Trichoderma harzianum growth and soil fertility. It achieved a spore count of 34 × 10⁵ CFU/mL, lowering disease incidence from 64 to 35%. This combination also resulted in an increased shoot length of 45.7 cm, root mass of 4.73 g/plant, and phenolic content of 0.49 µg GAE g(−1). CONCLUSION: The current study revealed that the biochar-cassia-T. harzianum combination enhances plant defense, manages soil-borne pathogens, and boosts crop productivity due to its phenolic content. This integrative approach offers a sustainable, eco-friendly strategy for managing soil-borne pathogens and improving crop productivity. Future research should investigate the underlying molecular mechanisms and expand its application to other crops and pathogens.