THE EFFECT OF SOIL MOISTURE ON THE GROWTH AND SPREAD OF CONIOPHORA PUTEANA UNDER LABORATORY CONDITIONS

Abstract

The effect of soil moisture and the related effect of some soil-inhabiting microorganisms on the spread through soil of the root-rotting Basidiomycete Coniophora puteana were studied. A soil moisture level of 20%–25% saturation was satisfactory for the growth of C. puteana in non-sterile soil. The fungus was able to grow out from a small alder disc inoculum in the center of a petri dish and invade alder discs at the periphery of the dish. At 50% saturation and higher C. puteana was unable to grow out into the soil. In autoclaved soil the optimum moisture level for the growth of C. puteana was between 75% and 100% saturation.Small amounts of non-sterile soil were added to autoclaved soil at different moisture levels, with an effect on the growth of C. puteana similar to that of completely non-sterile soil. Trichoderma viride, a known antibiotic producer, was inoculated into autoclaved soil and produced a greater inhibition of C. puteana in the wetter treatments than in drier ones. The inhibitory effect of Acti-dione (cycloheximide), an antifungal antibiotic, was examined in autoclaved soil. The same concentration of antibiotic resulted in a greater inhibition of the growth of C. puteana at the higher moisture levels than at the lower ones. Some implications of the findings are discussed.