A comparison of mycorrhizal and saprotrophic fungus tolerance to creosote in vitro

Twenty-six isolates (18 species) of mycorrhizal fungi and 13 isolates (13 species) of saprotrophic decay fungi were grown on agar amended with 25, 50 and 100 ppm creosote. All saprotrophic fungi exhibited some tolerance to creosote; 11 of 13 saprotrophic fungal isolates (85%) had intermediate, high or complete tolerance to creosote. However, only 12 of 26 mycorrhizal fungal isolates (46%) had comparable tolerance to creosote. Of the saprotrophic fungi, Irpex lacteus, Neolentinus lepideus, Ouedemansiella radicata, Phanaerochaete chrysosporium, Postia placenta and Trametes versicolor exhibited the greatest tolerance to creosote. Of the mycorrhizal fungi, Cenococcum geophilum, Laccaria bicolor (one isolate), Laccaria laccata (one isolate) and Suillus granulatus exhibited the highest tolerance to creosote. Mycorrhizal fungi with either very low or no tolerance (killed) by creosote were Amanita flavoconia, Astraeus hygrometricus, Lactarius rufus, Pisolithus tinctorius, and Scleroderma citrinum.