The emerald ash borer is causing dramatic losses following its introduction into North America, with hundreds of millions of ash trees killed. Attacked trees lose wood integrity rapidly after infestation and are prone to failure. The aim of this study was to investigate the wood degrading potential of Basidiomycota fungi previously found associated with EAB galleries. Laboratory soil and agar microcosm experiments showed that many of the white-rot fungi isolated were aggressive wood degraders. Trametes versicolor, Phlebia radiata and Phlebia acerina were among the top decomposers from the 13 tested fungi, resulting in as much as 70%, 72% and 64% weight loss, respectively, after 6 months of incubation. Micromorphological observations documented the significant wood cell wall degradation that had taken place. The decay capacity of these fungi confirms their contributing role to the loss of wood integrity in ash trees after EAB attack. © 2023 by the authors.