NATIVE RANGE: Southern Europe

FIRST FINDING IN SLOVENIA: 2003

PATHWAYS: transport of plant material

POSSIBLE TO FIND: year-round but easier to identify in June-August

DESCRIPTION: Endophyte, often present in healthy tissue but becoming parasitic in periods of drought or heat stress. The bark rots, cracks and peels in infected trees. Charcoal black fruiting bodies develop under the bark during the following season. Fruiting bodies are elongated with a raised edge, 1.8–7 cm long (sometimes up to 40 cm). Several fruiting bodies can merge together.

HOST PLANTS: Primarily cork oak (Quercus suber), Turkey oak (Q. cerris) and downy oak (Q. pubescens agg.). Less often and especially in periods of drought and heat stress, also manna ash (Fraxinus ornus), maples (Acer spp.) and other deciduous trees.

STATUS: Until the year 2003, it was known as a common cause of charcoal disease of oak trees in the Mediterranean region. Due to climate change, it is increasing in other parts of Europe. Found througout Slovenia. 

SIMILAR SPECIES: Biscogniauxia nummularia, which causes beech tarcrust, and other related species.

SOURCE: Field Guide to Invasive Alien Species in European Forests