EN
Dutch elm disease (DED) still occurs in Poland. Previous studies confirmed occurring O. ulmi and two subspecies of O. novo-ulmi: subsp. novo-ulmi and subsp. amerciana. In this study the population of Ophiostoma occurred in Poland was investigated. The disease incidence was investigated on elms growing in 39 locations. The pathogen’s mycelium was isolated from elm branches and twigs collected from 22 plots. The disease symptoms were noted in 5% to 35% trees. Fungi were identified based on the PCR amplification of the ITS 1/2 rDNA together with phylogenetic analysis of this region. Ophiostoma novo-ulmi was the only agent caused DED on Ulmus glabra, U. minor and U. laevis. There were no genetic diversity of O. novo-ulmi Polish population in analyzed ITS region. All kind of specific symptoms and disease intensity occurred independently on elm species and host age. Ulmus minor was infested most sever among the three elms species.