Isolation and Characterization of in Planta Antagonists of Fusarium Oxysporum F. Sp. Cubense

Seven (7) potential biological control agents were isolated from the roots of apparently healthy banana plants localized in a field suspected of Fusarium infection as exhibited by external symptoms of affected plants. Five (5) of the isolates were rhizospheric microbes and two (2) were putative bacterial endophytes (EB101 and EB102) isolated from chemically-surface sterilized root samples. The rhizospheric microbes isolated herein comprised of four (4) bacteria (RBI01, RB102, RB103 and RB104) and one (1) fungal isolate (RFI01). Morphological and cultural assessment of the potential biocontrol agents of Fusarium oxysporum f. Sp. Cubense (Foc) were done to aid in the characterization of the different microbial isolates. Efficacy of the different putative biological control agents were initially assessed using Paper Disc Method. Out of the seven isolates, RFI01, EB101, RB102, RB103 and RB104 demonstrated significant inhibition of Foc by as much as 83%. RB104 and EB101 also show significant antagonistic activity against Foc ( Al = 1.33 and 0.94 respectively.) Growth reduction of Foc as observed in Dual Culture Plate set-ups confirms the efficacy of the mentioned potential biological control isolates of Foc through coinciding data where RF101 lead Foc inhibition (85% growth reduction) followed by RBI04 (25.93% growth reduction) and EBI01 (22.23% growth reduction). Growth reduction rate of Foc as exhibited by the different isolates were significantly different from each other based on One-Way ANOVA and Tukey's HSD Test done to assess the data given.