Native Trichoderma spp. as biocontrol agents against common beans anthracnose

Trichoderma spp. has emerged as a promising biocontrol agent among soil microbiota. This study evaluated the potential of 32 Trichoderma isolates, obtained from Araucaria Forest soils in southern Brazil to control Colletotrichum lindemuthianum (races 475 and 73), the causative agent of anthracnose in common bean ( Phaseolus vulgaris L.). In vitro assays including dual culture, volatile and non-volatile metabolite production, and fungicide compatibility were conducted. T. hamatum LMA RQ, T. asperellum LMA RS2, and T. atroviride LMA PH were the most promising strains. These isolates were further assessed in detached leaf, pod and seed germination assays using the IPR-Uirapuru and IAC-Veloz cultivars. Notably, T. hamatum LMA RQ showed comparable or superior performance to chemical and commercial biocontrol standards, promoting full seed germination, reducing disease incidence to zero in seeds, and lowering disease severity in pods and leaves. T. asperellum LMA RS2 and T. atroviride LMA PH also demonstrated strong biocontrol performance and compatibility with fungicides. The mechanisms involved included mycoparasitism, competition, and metabolite production. All effective isolates were applied as spore suspensions without adjuvants, supporting their potential for the development of commercial biofungicides. These findings highlight the potential of native Trichoderma spp. as sustainable alternatives to chemical control in anthracnose management in common bean cultivation. Their efficacy now depends on further validation in greenhouse and field trials.