Investigating the impact of temperature on growth rate of the root rot fungus, Gymnopus fusipes

is an understudied root rot pathogen associated with multiple tree species and is linked to episodes of oak decline across the United Kingdom and Europe. Although the reported distribution of is broad, many observations rely solely on visual identification of fruiting bodies, which can be unreliable, and lack confirmation by molecular and/or isolation data to verify this broad ecological range. Given the paucity of information regarding the true ecological distribution of , it is difficult to predict and model the potential distribution of the species under both current and future climate scenarios. In this study, to determine the growth capabilities of across a range of ecologically relevant temperatures five geographically diverse isolates of were grown at five different temperatures ranging from 4-37°C, to determine the optimal temperature for growth, and to establish whether geographically diverse isolates exhibit local adaptation to temperature tolerance. Incubation temperature had a significant effect on growth rate, with 25°C representing the optimum (