Rosellinia aquila Among Fungi on Branches of Sessile Oak with Symptoms of Decline

Rosellinia aquila was found for the first time in crowns of sessile oaks, Quercus robur (Mattuschka) Liebl., with symptoms of decline. The fungus occurred mostly on diseased branches but also colonized twigs with healthy appearance. Its anamorph and teleomorph stages were produced abundantly on dead branches after long incubation in moist conditions. Colonization of oak trees by R. aquila was likely to have been facilitated by higher humidity and temperature in the oak stands.