Fungi causing powdery mildew on plants of a Botanical Garden in Southern Finland

Authors: Heiskanen, Ville J. & Valkonen, Jari P. T.
Journal: Karstenia, Volume 59 (2021), Issue 1-2, pages 13-29.
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Key words: botanic garden, Erysiphales, internal transcribed spacer (ITS), powdery mildew, Southern Finland

Abstract: Fungi that cause powdery mildew on plants are plant pathogenic parasites (Erysiphales) and can significantly reduce the ornamental value of plants and cause significant yield losses among cultivated plants. In this study, 94 plant accessions infected with powdery mildew were observed in Kumpula Botanic Garden, Helsinki, Finland, in 2015. The taxonomic affiliation and species richness of powdery mildew fungi were investigated. Morphological studies by microscope distinguished only 14 fungal species, whereas further comparisons of internal transcribed spacer (ITS) sequences enabled the identification of 28 species. Hence, ITS sequencing improved the reliability of species determination, as compared with the use of morphological characteristics only. The vegetation in an area of six hectares supported a wide range of fungi that cause powdery mildew as well as hyperparasitic microbes, which may balance the impact of pathogens in host plants. The findings of this study emphasize the role of botanical gardens in protecting biological diversity in urban areas.


Table S1. Fungal isolates observed at the anamorph
stage with a focus on their mycelia and conidia.
Table S2. Fungal isolates observed at the teleomorph
stage with a focus on chasmothecia, asci, and