Evaluation of Biocontrol of Mycosphaerella fijiensis by five Species of Rhizosphere Fungi of Plantain.

This study assessed the efficacy of certain rhizosphere fungi isolated from banana plantations in the Haut-Sassandra region as biocontrol agents against Mycosphaerella fijiensis, responsible for banana black spot. It involved characterizing banana leaf and rhizosphere fungi and studying the antagonistic activity of rhizosphere fungi on M. fijiensis. Analyses identified isolates M9 and M10 as M. fijiensis. Five fungal species were isolated from the rhizosphere: T. ghanense, T. longibrachiatum, T. reesei, Neurospora dictyophora and H. terricola. In vitro tests revealed that these fungi inhibit the growth of M. fijiensis, using antagonistic mechanisms such as competition, antibiosis and mycoparasitism. The strongest antagonistic activity was observed with N. dictyophora. Moreover, the extracts derived from these antagonists showed high antifungal activity, with total inhibition of M. fijiensis from 2.5 mg/mL upwards. The minimum fungicidal concentration (MFC) for all extracts was 5 mg/mL, except for T. ghanense which showed an MFC of 10 mg/mL. These results suggest that the rhizospheric fungi studied are promising candidates for the development of M. fijiensis biocontrol strategies.