Biological Control Potential of Trichoderma asperellum Against Rhizoctonia solani Causing Root Rot in Bean

Abstract

Soil-borne fungal pathogens such as Rhizoctonia solani are major constraints in bean production, causing root rot, seedling mortality, and significant yield losses. The present study evaluated the biological control potential of Trichoderma asperellum against R. solani responsible for root rot in bean under controlled conditions. Dual culture assays and greenhouse experiments were conducted to assess antagonistic activity, disease suppression, plant growth promotion, and root colonization ability of the biocontrol agent. The results demonstrated that T. asperellum exhibited strong antagonism against R. solani, significantly inhibiting mycelial growth through competition, mycoparasitism, and production of antifungal metabolites. In treated plants, a marked reduction in root rot incidence and disease severity was observed compared to untreated controls. Enhanced seedling vigor, improved root development, and increased biomass accumulation were recorded in Trichoderma-treated bean plants, indicating additional plant growth-promoting effects. The biocontrol fungus effectively colonized the rhizosphere and persisted in the root zone, contributing to long-term suppression of the pathogen. Enzymatic activity and antibiosis were identified as key mechanisms involved in pathogen inhibition. Environmental conditions influenced the efficiency of biocontrol, with optimal soil moisture and temperature enhancing Trichoderma activity. The findings highlight the dual role of T. asperellum as both a biocontrol agent and plant growth promoter in bean cultivation systems. This study supports the integration of Trichoderma-based formulations into sustainable disease management strategies aimed at reducing reliance on chemical fungicides and improving bean productivity.