Bark beetle-associated fungi in Fennoscandia with special emphasis on species of Ophiostoma and Grosmannia

Abstract

Global trade in untreated timber and wood products raises the risk of accidentally introducing forest pests and pathogens into new environments. Bark beetles (Coleoptera: Scolytinae) include several species that are regarded as forest pests. These insects are known to live in close association with fungi, especially species of ophiostomatoid fungi (Ascomycota). Several of these fungi are agents of blue stain in timber, and some are serious plant pathogens. However, only little is known regarding the fungal associates of bark beetles, or the interactions between the fungus, the bark beetle and the host tree in the boreal forests of Fennoscandia.The aim of this study was to increase the knowledge regarding bark beetle-associated fungi in Fennoscandia, with special emphasis on the genera Ophiostoma Syd. & P. Syd. and Grosmannia Goid. Fungi associated with 13 different bark beetle species, infesting Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and birches (Betula L. spp.) in the eastern parts of Finland and neighboring Russia, as well as southern Norway, were isolated and identified. The fungal identifications were based on morphological characteristics and DNA sequence comparisons.The survey revealed the occurrence of at least 29 species of Ophiostoma and Grosmannia. All the bark beetle species considered in this study were frequently associated with a complex of ophiostomatoid fungi. Several species were recorded for the first time in the countries in the study. A surprisingly high number of previously undescribed fungal species were discovered. During the survey, eight of these species were described as new taxa. In addition, the study revealed new insect-fungus relationships. The number of taxa encountered, covering a relatively small geographical area, indicates that there are many more ophiostomatoid fungi occurring in the boreal forests of Fennoscandia than has previously been recognized. The study emphasizes the importance of developing a clear understanding of the possible threats of moving timber and wood products without knowledge of the micro-organisms that might also be moved.Keywords: blue stain, insect-fungus interactions, molecular systematics, ophiostomatoid fungi, Ophiostomatales, symbioses 4 ACKNOWLEDGEMENTS "It's the journey that's important, not the getting there" (John McLeod). The writing of this dissertation has been a fascinating journey full of unforgettable experiences, from South African sunrises to a rail ride on the Trans Siberian Railway. It has also been a time of personal growth. The writing of a dissertation is a long journey, and obviously not possible without the support of numerous people. I've been truly privileged to start my journey in the world of science with many inspiring people. It's been a great pleasure to follow their enthusiasm and the deep commitment to the work they love. Thank you for passing on the passion for science! I would like to express my sincere thanks to all of you who have contributed and supported this project in v...

The Ophiostoma clavatum species complex: a newly defined group in the Ophiostomatales including three novel taxa

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Fungi associated with Ips acuminatus (Coleoptera: Curculionidae) in Ukraine with a special emphasis on pathogenicity of ophiostomatoid species

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