Biocontrol efficacy of Trichoderma harzianum and Trichoderma virens against different soil-borne fungal pathogens

ABSTRACT An experimental investigation was carried out to evaluate the biocontrol efficacy of two Trichoderma species on pathogenic fungi isolated from the rhizospheric soil. Experiments revealed the beneficial interactions between the test biocontrol agents against the isolated pathogenic fungi. Two Trichoderma species viz. T. harzianum, and T. virens were assessed for their biological control efficiency against ten different pathogenic fungi viz. Alternaria alternata, Chaetomium cochliodes, Cladosporium cladosporoides, Colletotrichum fructicola, Curvularia lunata, Fusarium oxysporum, F. ventrichosum, F. proliferatum, F. solani and Mucor hiemalis. T. harzianum exhibited the highest mycelial growth inhibition against F. solani (71%), followed by C. cochliodes and C. lunata (70%), F. ventrichosum (69%), and C. fructicola (68%). Moderate inhibition was recorded against F. oxysporum, A. alternata, C. cladosporioides, and F. proliferatum (58–65%), while the lowest inhibition (44%) was observed against M. hiemalis. Similarly, T. virens showed maximum mycelial growth inhibition against C. fructicola (80%), followed by F. oxysporum (75%), C. cochliodes and C. lunata (72%), and F. proliferatum (70%). Inhibition against F. solani, A. alternata, F. ventrichosum and C. cladosporoides ranged from 59–68%, while the lowest inhibition was observed against M. hiemalis (54%). The study also assessed parameters such as the time to colony contact, overgrowth, and plate coverage by the biocontrol agent, pathogen radial growth, resistance, and Pakdaman’s Biological Control Index (PBCI). These attributes collectively also revealed the significant biocontrol efficacy of T. virens and T. harzianum against the tested soil-borne fungal pathogens. Keywords: Dual culture; confrontation; Trichoderma; growth inhibition; pathogen resistance