Mistletoe (Viscum album) is a semi-parasite of many forest trees. During water scarcity, its presence can be particularly dangerous for the host plant. In Poland, the subspecies V. album subsp. austriacum inhabits Scots pine massively. Therefore, an attempt was made to search for a natural barrier in limiting its development. For this purpose, in spring 2019 in the southwestern part of Poland, mistletoe shoots inhabiting Scots pine were collected. A fungus was isolated from the collected plant fragments, which was then identified by Koch’s postulates and DNA analysis of the given sequences. The data presented here confirmed that the pathogen responsible for the disease was Sphaeropsis visci. This is the first report on the occurrence of this mistletoe pathogen in Poland.
Keywords: Sphaeropsis visci, Viscum album subsp. austriacum, New pathogen, Scots pine, Mistletoe