Inhibition of Fungal Pathogens of Pleurotus tuber-Regium (Fries) Singer using Trichoderma harzianum and Trichoderma Viride

This study was carried out to compare the potentials of Trichoderma Harzanium and Trichoderma viride to inhibit the radial mycelial growth of three fungal pathogens (Aspergillus niger, A. flavus and A. ochraceous) of Pleurotus tuber-regium. Each Trichoderma strain was paired with each pathogen on 9 cm Petri plates of acidified potato dextrose agar using three pairing methods. These were: inoculation of pathogens before the antagonists (Trichoderma spp.), inoculation of pathogens simultaneously with the antagonist and inoculation of pathogens after the antagonist. Plates obtained from the three treatments were then incubated for different period of 48, 72, 96, 120, 144 and 168 hours. Varying estimated growth inhibitions of pathogens by Trichoderma strains were subjected to analysis of variance (ANOVA) to determine the significance of differences using SPSS version 17.0. The result of the study depicted that in all the three treatment combinations, the radial mycelial growth of all the Aspergillus pathogens were inhibited by the two species of Trichoderma antagonist. However, the degree of inhibition was treatment specific. For instance, the percentage inhibition was significantly higher (Pless than 0.05) in all the treatments where the antagonist was inoculated before the introduction of the pathogen while the least inhibition was observed when the pathogen was inoculated before the introduction of the antagonist. A. niger was not highly inhibited compared to the other pathogens. In addition, T. harzanium. Appeared to demonstrated greater antagonistic activity between 24 and 144 hours of incubation. However, at the 168th hour of incubation there appeared to be no significant difference between the antagonistic activities of the two Trichodermaspp against the investigated pathogens. Results of the present study suggest that Trichoderma spp. used in this study could be exploited as biopesticides in the control of Aspergillus. Pathogens of P.tuber-regium.