Green moulds caused by Trichoderma result in considerable losses in the growing of several species of cultivated and medicinal mushrooms. Pholiota nameko is a mushroom species well-known in many Asian countries. The aim of the studies was to determine the effect of substrate infestation with Trichoderma isolates on yielding of P. nameko. The experiment was conducted on four strains of P. nameko, i.e. PN01, PN04, PN05 and PN06. The substrate was infested with isolate T361, belonging to the species T. aggressivum f. europaeum and isolate Th14/5, belonging to the species T. harzianum. Infestation of the substrate with both isolates of Trichoderma resulted in a reduction of yield in the analysed strains of P. nameko. A markedly greater yield reduction was caused by infestation with isolate T361 than isolate Th14/5. Infestation of the substrate with the analysed Trichoderma isolates to a slight extent influenced mean weight of fruiting bodies in P. nameko and their morphological traits, such as cap diameter, and stem length and diameter. Substrate infestation with Trichoderma isolates had no effect on dry matter content of carpophores.

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