The effect of stilbenes on decay fungi of birch and aspen
L Syrjälä, K Von Weissenberg, A Pappinen, L Paajanen
Fourteen species of decay fungi, mainly species growing on birch and aspen, one leaf spot fungus of birch and the pine canker fungus Gremmeniella abietina were used to investigate how the stilbenes resveratrol and pinosylvin influence their relative growth on malt agar. With some species the ability to decay with stilbenes impregnated wood was also studied. The concentration of pinosylvin needed to prevent their growth on agar was 70 - 100 mg/ml for most of the decay fungi. Phellinus pini was least influenced. Resveratrol prevented the growth of Cerrena unicolor on 250 mg/ml but not of any other decay fungus even on 400µ g/ml. Higher resveratrol concentrations reduced the growth of all other species but P. pini and Phellinus tremulae, however, P. tremulae started to grow as fast growing bleaching type on resveratrol containing media, while on control plates it grew as the slowly growing staining type. The leaf spot fungus of birch and G. abietina were both relatively resistant to the two stilbenes. Between fungus strains there were sometimes big differences in resistance. The ability of Piptoporus betulinus and Stereum hirsutum to decay impregnated wood samples was prevented at 0.8% w/w pinosylvin. The decay caused by Trametes versicolor and Phellinus tremulae was reduced but not prevented at this concentration. Resveratrol reduced at 0.8% w/w decay caused by T. versicolor but not by P. betulinus.