Canker Stain: A Lethal Disease Destroying Iconic Plane Trees

In Europe, both Oriental plane and London plane trees are seriously threatened by the invasive fungal pathogen Ceratocystis platani (Walter) Engelbr. & T.C. Harr., the causal agent of canker stain disease (CSD) of plane trees. The fungus is considered to be indigenous to North America and was accidently introduced into Europe during World War II, where it continues to spread clonally. The impact of CSD in Europe can be compared with notorious tree diseases such as Dutch elm disease, chestnut blight, and more recently Ash dieback, which have all caused devastating losses to natural woody ecosystems and ornamental trees. In Italy and France, C. platani has caused widespread mortality to London plane trees and the pathogen has also been recorded in Switzerland and Spain. However, the most dramatic impact of the disease has been in Greece in natural stands of Oriental plane. The objective of this feature article is to review current knowledge regarding CSD and to highlight the dramatic and devastating nature of the disease. An important aim is also to highlight the risk of C. platani spreading northward in Europe and eastward to Asia in the natural and cultivated range of oriental and London plane.