A Summary of Literature References of Factors Affecting Moisture Content Determination with D.C. Resistance Measurements

The protective effect of ectomycorrhizae of Pinus patula Schlecht. et Cham against the root pathogen Phytophthora cinnamomi was investigated. Three methods were employed to evaluate this effect. Firstly, extracts were prepared from the root systems of mycorrhizal plants and tested for antibiotic activity against P. cinnamomi. Secondly, fungal antagonism between two mycobionts Amanita muscaria and Boletus edulis, and the pathogen was tested for in vitro; and thirdly, in situ studies were conducted to determine the protective effect afforded under natural conditions. No fungal antagonism was observed in vitro, but significant protection was obtained in situ and when the pathogen was exposed to the extracts. The mechanism involved could thus probably be attributed to the production of antibiotic substances by the macrobiont and mycobiont, and the formation of a physical barrier, the Hartig-net and the fungal mantle.