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.
The six-toothed bark beetle (Ips sexdentatus) is known to be associated with ophiostomatoid fungi. However, very little is known about these fungi in Poland. The aim of this study was: 1) to identify fungi of Ophiostoma s. lato carried by this bark beetle and 2) to test the pathogenicity of several commonly occurring fungi. Isolations were carried out from the beetles and their galleries at three sites in Poland. Samples yielded a total 3162 cultures, which included 10 species of Ophiostoma s. lato. The most frequently encountered fungal associates of I. sexdentatus were L. cf. truncatum, O. brunneo-ciliatum and O. ips. Ophiostoma cf. rectangulosporium, O. cf. abietinum, O. quercus and O. floccosum appeared to be also specifically associated with I. sexdentatus. Leptographium cf. truncatum and O. minus were most virulent and can be consideredas serious pine pathogens.