Fungitoxicity of <i>Trichoderma longibrachiatum</i> (Rifai) Metabolites against <i>Fusarium oxysporum</i>, <i>Aspergillus niger</i> and <i>Aspergillus tamarii</i>

Abstract

An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on F. oxysporum, A. niger and A. tamarii. The fungi were collected from the International Institute of Tropical Agriculture (IITA) and Nigerian Institute of Science Laboratory Technology (NISLT). T. longibrachiatum was cultured on 1/4 strength Potato Dextrose Broth (PDB) following standard procedures. Its metabolite was extracted using 50 ml n-hexane with 50 ml Potato Dextrose Broth (PDB). The metabolite was purified by filter sterilization using a sterile 0.22 millipore filter disc after centrifuging at 900 rpm for 20 minutes. Petri plates of each fungus were later impregnated in triplicates with the T. longibrachiatum metabolites using four concentrations (10%, 25%, 50% and 100%), and three volumes (1 ml, 2 ml, and 3 ml). Petri plates of fungi without the metabolite and Petri Plates of fungi with n-hexane and PDB served as control. All Petri Plates were incubated at 28°C for 7 days. Radial and diametric growth of each fungus on all Petri Plates were taken daily at 24 hours intervals. Data obtained were analysed using SAS (version 9.3). Growth inhibition of F. oxysporum, A. niger and A. tamarii was significantly higher than in control in that order (P ≤ 0.05). Inhibition of the fungi by metabolites extracted with both PDB and n-hexane was significantly better than in control. Generally, inhibition by metabolite extracted with PDB was better than that extracted with n-hexane. Growth inhibition at all the concentrations of the metabolite was significantly better than in the control (P ≤ 0.05). Generally, inhibition at 100%, 50% and 25% concentrations was better than that at 10% concentration of the metabolite. Trichoderma longibrachiatum metabolite can thus be said to possess promising fungitoxic potential even at concentrations as low as 25%. Both PDB and n-hexane are good extraction media for the metabolite.