Potential of Trichoderma species to control Rosellinia necatrix, the etiological agent of white root rot

Abstract

White root rot, caused by the fungal pathogen Dematophora necatrix (syn. Rosellinia necatrix), poses a threat to crops worldwide, leading to substantial economic losses. Biological control using antagonistic fungi, such as Trichoderma spp., has emerged as a promising alternative to chemical fungicides in fungal disease management. In this study, we investigated the potential of three Trichoderma species, Trichoderma harzianum strain 40788 from the Korean Agriculture Culture Collection (KACC), T. atroviride (KACC 43393), and T. asperellum (KACC 43821), as biocontrol agents against four R. necatrix strains (KACC 40446, 40445, 40447, and 40168). Dual-culture assays revealed that T. harzianum (KACC 40788) and T. atroviride (KACC 43393) rapidly inhibited mycelial growth, achieving up to 80% suppression of strains KACC 40445 and KACC 40446, whereas T. asperellum (KACC 43821) exhibited lower inhibition. In volatile antibiotic production assays, volatile metabolites produced by T. harzianum (KACC 40788) and T. atroviride (KACC 43393) inhibited mycelial growth of R. necatrix strains KACC 40445 and KACC 40446 by 76.52 and 74.70%, respectively. Microscopic analysis of mycoparasitism revealed that Trichoderma strains adhered to, coiled around, and lysed R. necatrix mycelia. Finally, greenhouse trials demonstrated that T. harzianum and T. atroviride treatment significantly reduced white root rot incidence, with disease symptoms in only 15% of treated pear saplings, compared with 82% in untreated controls. Collectively, our findings highlight the potential of T. harzianum and T. atroviride as effective biocontrol agents against white root rot caused by R. necatrix, thereby providing sustainable and environmental-friendly disease management strategies in agricultural systems.