Biscogniauxia Charcoal Canker—A New Potential Threat for Mid-European Forests as an Effect of Climate Change

Abstract

Biscogniauxia nummularia (Bull.) Kuntze is a fungus which induces strip-cankers on beech, commonly referred to as charcoal canker. The symptoms of infection are visible on the host tree’s bark as elongated, blackish bark lesions on the trunk and branches. Recent years have shown that, due to climate change causing local epidemics, the species is increasing its economic impact in Mediterranean regions. Until recently, B. nummularia was considered rare and uncommon in central Europe. However, in the last few years it has been noticed more often, mostly in coniferous trees, which are out of B. nummularia’s host range. A similar situation has been observed with the closely related species Biscogniauxia mediterranea (De Not.) Kuntze, which prior to 2017 had not been observed in central Europe at all. This study shows the genetic diversity of mid-European strains of Biscogniauxia spp. (based on the ITS, TEF1, TUB2 and ACT regions) and, as the first in Europe, presents a molecular investigation of this species isolated from coniferous trees. It is also the first attempt at estimating the potential impact of this pathogenic fungus on European forestry management in the close future.

Identification and Pathogenicity of Biscogniauxia and Sordaria Species Isolated from Olive Trees

“…A genetic analysis of the isolates revealed no significant genetic distinctions compared to the majority of other isolates. As indicated by Patejuk et al [42] in their research, this implies a potential natural drift of the fungus into Europe.…”

“…Patejuk et al [42] state that many authors have emphasised that B. nummularia behaves mainly as a saprophyte in the northern Mediterranean basin, where the climate is more temperate. In Europe, it is most commonly described as a pathogen of the plant species F. sylvatica [37].…”

“…Patejuk et al [42] emphasise the importance of conducting pathogenicity tests to demonstrate the pathogenic nature of the species. As part of this study, pathogenicity tests were conducted on seedlings of five different olive varieties: 'Buža', 'Istarska bjelica', 'Leccino', 'Porečka rosulja' and 'Rosinjola'.…”

“…beech tarcrust, charcoal canker, hypoxylon canker) on European beech (Fagus sylvatica L.) and sedge (Carex brevicollis DC.) [36,41,42].…”

Biscogniauxia rosacearum: A newly identified pathogen of strawberry tree (Arbutus unedo L.) in North Africa

“…Species of Biscogniauxia, as xylariaceous fungi, are well known for living in plant tissues without development of symptoms (Luchi et al, 2015), as well as causing necrosis on stems and branches, leaf discoloration and dryness in young trees (Henriques et al, 2016). Additionally, the presence of xylariaceous fungi in green leaves of evergreen angiosperm shrubs and trees has been confirmed in other studies, underscoring the unexpected ecological significance of these fungi (Gharbi et al, 2020;Govinda Rajulu et al, 2013;Patejuk et al, 2022;Yangui et al, 2019Yangui et al, , 2021.…”