EN
Growth of Trichoderma pleurotum and T. pleuroticola isolates on the Potato Dextrose Agar (PDA) medium was investigated. T. pleuroticola isolates showed a significantly greater diameter of their mycelium colonies after 5 days of incubation than the T. pleurotum isolates. In addition, biotic interactions between T. pleurotum and T. pleuroticola isolates and species of Pleurotus sp. were determined. The following six species of oyster mushroom were used: P. florida, P. cornucopiae, P. pulmonarius, P. columbinus, P. ostreatus and P. eryngii. It was demonstrated that isolates of the T. pleuroticola species limited the growth of the examined species of oyster mushroom to a much greater extent than the isolates of the T. pleurotum species.