This report gives an overview of the outbreak, spread, research and response to ash dieback, a disease of European ash (Fraxinus) caused by the fungal pathogen Hymenoscyphus fraxineus.

Abstract

Ash dieback is a disease caused by the fungal pathogen Hymenoscyphus fraxineus. Since its emergence in the 1990s, this pandemic disease has spread throughout much of the native range of its host species, the European ash (Fraxinus excelsior). Where present, it can kill up to 85% of ash trees. The loss of these trees has had an enormous impact, particularly in Britain and Ireland where they formed an integral component of wood and farmland, supporting complex communities of other species. Thanks in part to widespread public interest, the ash dieback pandemic has also had a large political impact, leading to changes in the management of plant diseases. Now, three decades after the emergence of the disease, ambitious projects to breed tolerant plants, and evidence of natural selection for resistance, give hope for the recovery of European ash. The aim of this review is to provide an overview of the history of the ash dieback pandemic, from its emergence to current efforts to mitigate its effects. We discuss the emergence of ash dieback and the wide body of research that has led to our current understanding of the disease. We question which aspects of the disease have led to it holding a particular interest to the public. With a focus on the islands of Britain and Ireland, we discuss how this has driven changes in the management of plant diseases, which may give hope for the control of emerging pathogens in the future.