Antagonistic activity of Trichoderma species on phytopathogens of Phaseolus vulgaris L.

The common bean (Phaseolus vulgaris L.) is crucial for human nutrition, providing proteins and essential nutrients to millions of families globally. This crop faces significant challenges from diseases caused by phytopathogenic fungi like Macrophomina phaseolina and Fusarium spp.. Trichoderma sp. is known for its ability to produce secondary metabolites with antagonistic properties against various phytopathogens. This study aimed to evaluate the antagonistic potential of volatile and non-volatile metabolites produced by Trichoderma in inhibiting the mycelial growth of Macrophomina phaseolina, Fusarium triseptatum, Fusarium annulatum, and Fusarium fabacearum. Tests involved three Trichoderma species (T. asperelloides, T. asperellum, and T. afroharzianum). Volatile metabolites were tested using the double plate method, while non-volatile metabolites were assessed by incorporating Trichoderma filtrate into 25% Potato Dextrose Agar (PDA), with the pathogen placed in the Petri dish center. Results demonstrated that both types of metabolites effectively controlled phytopathogens, with T. asperelloides (URM8945 and URM8946) showing notable inhibition of M. phaseolina isolates, and T. asperellum (URM8998) and T. afroharzianum (URM8938) exhibiting activity against F. annulatum. Volatile compounds were generally more effective against Fusarium spp. isolates compared to non-volatile metabolites. Therefore, metabolites from these Trichoderma species should be considered for sustainable disease management in common bean crops.