Sooty bark disease of sycamore is spreading in Europe
Sooty bark disease of sycamore (Acer pseudoplatanus) is caused by Cryptostroma corticale, a fungus considered to be native to Eastern North America. Other species of Acer (A. campestre, A. platanoides), as well as ash trees (Fraxinus excelsior) may also be affected to a lesser extent. In Europe, sooty bark disease of sycamore was first reported in England (United Kingdom) in 1945 and in France in 1951, followed by sporadic records in other European countries. After 2000, the disease has been more frequently reported in Europe (e.g. Czech Republic, France, Germany, Switzerland) with more severe damage.
An updated distribution map of is available in EPPO Global Database https://gd.eppo.int/taxon/CRPSCO/distribution.
Cryptostroma corticale may be an endophyte on sycamore, as well as on ash trees (F. excelsior). Recent research underlined the role of climate change in the emergence of the disease with severe outbreaks being observed after periods of drought. As drought periods are predicted to increase in the Mediterranean basin and Western and Central Europe in the following decades, a further expansion and intensification of this disease can be expected. Spores (conidia) of the fungus can be spread over 300 km in the air. Aerobiological surveillance with suction traps appears to be an effective tool for early detection.
It may be noted that, in addition to impact on plant health, C. corticale has impacts on human health as workers processing infected wood can develop hypersensitivity pneumonitis (maple bark strippers’ lung).
Sources
Kespohl S, Riebesehl J, Grüner J, Raulf M (2022) Impact of climate change on wood and woodworkers—Cryptostroma corticale (sooty bark disease): A risk factor for trees and exposed employees. Frontiers in Public Health 10, https://doi.org/10.3389/fpubh.2022.973686
Langer GJ, Peters S, Bußkamp J, Bien S (2023) Cryptostroma corticale and fungal endophytes associated with Fraxinus excelsior affected by ash dieback. Journal of Plant Diseases and Protection. https://doi.org/10.1007/s41348-023-00750-8.
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Schlößer R, Bien S, Langer GJ, Langer EJ (2023) Fungi associated with woody tissues of Acer pseudoplatanus in forest stands with different health status concerning sooty bark disease (Cryptostroma corticale). Mycological Progress 22(2), 13. https://doi.org/10.1007/s11557-022-01861-6