Investigation of the risk potential of Pleurotus ostreatus and Flammulina velutipes within the horse chestnut complex disease , Untersuchung des Gefahrenpotentials von Pleurotus ostreatus und Flammulina velutipes innerhalb der Rosskastanien-Komplexkrankheit

The horse chestnut complex disease is caused by the bacterium Pseudomonas syringae pv. aesculi. As a consequence, rapid wood decomposition is observed due to the oyster mushroom (Pleurotus ostreatus) and the velvet toadstool (Flammulina velutipes). In order to investigate the risk potential of the following organisms for the tree, the oyster mushroom (P. ostreatus) and the velvet foot fungus (F. velutipes), two series of in vitro tests were carried out with mono, dual and multiplex cultures. In the first series of experiments, the influence of the basidiomycetes on each other and the influence of the bacterium on the basidiomycetes was analysed by measuring radial mycelial growth. The second series of experiments were used to investigate the wood decomposition behaviour of the fungi in mono and dual culture. The test results show that F. velutipes poses a greater potential risk than P. ostreatus when the bacterium P. syringae pv. aesculi is involved. The hazard potential of F. velutipes is apparently increased by the synergistic effect of the neobiont Pseudomonas syringae pv. aesculi on mycelial growth, so that the fungus only becomes a problem for trees of the genus Aesculus and in the assessment of traffic safety due to the presence of the bacterium.