THE INFLUENCE OF PH ON BIODETERIORATION OF A TROPICAL TIMBER EXPOSED TO MIXED CULTURES OF BIOCONTROL AND WOOD-ROT FUNGI

A laboratory investigation of the decay control potentials of Trichode rma viride and Penicillium sp. on the deterioration of obeche wood (Tr iplochiton scleroxylon), buffered at various pH, by wood-rot fungi (Gl oeophyllum sp. and Gloeophyllum sepiarium), was carried out. Biomass d eterminations in carboxylmethyl cellulose broth at various pH showed t hat the biocontrol fungal strains exployed grew better as the pH appro ached neutral while the reverse was true for the wood-rot fungi. Deter ioration of wood (buffered at various pH) simultaneously inoculated wi th the biocontrol and wood-rot fungi was more markedly reduced towards neutral pH than at lower pH values. Decay begun in wood initially inf ested with rot fungi before inoculation with biocontrol fungi was virt ually halted at neutral pH, which was not the case in lower pH (2 and 3) buffered wood simultaneously inoculated with biocontrol and wood-ro t fungi. A killing effect was indicated when the rot fungi failed to a ppear on potato-dextrose agar from interior sections of the wood block s. Manipulation of pH may prove important in biological control of woo d decay.