Efficacy of five Trichoderma species against anthracnose in pecan through mycoparasitism and antibiosis

Abstract Among the various diseases occurring in the pecan tree crop, anthracnose, caused by species of the genus Colletotrichum, stands out. Biocontrol using Trichoderma presents as a promising measure to be used in disease control because it has a broad spectrum of action on phytopathogens, enables the activation of the defense system, and the promotion of plant growth, contributes to environmental sustainability and food security. This work aimed to investigate the in vitro antagonistic action of Trichoderma species on Colletotrichum, the etiological agent of anthracnose in pecan. The dual-culture assay and the inhibition test by volatile metabolites were performed with five species of Trichoderma (T. harzianum, T. koningiopsis, T. asperellum, T. tomentosum, and T. virens). Mycelial growth was evaluated daily until the seventh day. In the dual-culture assay, all species showed antagonist potential, inhibiting the mycelial growth of the pathogens from the third day onward. Trichoderma virens and T. tomentosum showed greater antagonist potential and stood out in the volatile metabolites.