Ash decline in Nordic and Baltic countries

Information gathered by the PATHCAR project


  • Shoot dieback
  • Necrotic bark on shoots
  • Necrotic tops, leaves and branchlets
  • Bark wounds
  • Stem cankers
  • Caused most probably by an ascomycetous fungus Chalara fraxinea T. Kowalski sp. nov.
ash dieback - click for larger image
Foto: Pia Barklund (click to enlarge)


  • The symptoms were first observed in Poland and Lithuania in early 1990´s
  • Since mid 1990´s, in Latvia and Estonia
  • Since the beginning of 2000´s, in Germany, Denmark, Sweden and the Åland archipelago of Finland
  • Not observed in Norway, Iceland or continental Finland
  • Holotypus: cultura desiccata ex ramo Fraxini excelsioris, in herbario Zuerich (Z + ZT), T. Kowalski legit, Polonia, Włoszczowa, 06.12.2000 isolata, cultura viva in CBS, Utrecht, Hollandia.
Foto Pia Barklund - click for larger image
Foto: Pia Barklund (click to enlarge)

More information


  • Lygis, V., Vasiliauskas, R, Larsson, K.H. & Stenlid, J. 2005. Wood-inhabiting fungi in stems of Fraxinus excelsior in declining ash stands of northern Lithuania, with particular reference to Armillaria cepistipes. Scandinavian Journal of Forest Research 20, 337-346.
  • Barklund, P. 2005. Sjukdom på ask spridd över hela Syd-och Mellansverige. Skogseko 3: 9.
  • Barklund, P. 2006. Okänd svamp bakom askskottsjukan. Värsta farsoten som drabbat en enskild trädart. Skogseko 3: 10-11.
  • Kowalski, T. 2006. Chalara fraxinea sp. nov. associated with dieback of ash (Fraxinus excelsior) in Poland. Forest Pathology 36: 264-270
  • Thomsen, I.M.; Skovsgaard, J.P. 2006. Skoven 9: 408-411.
  • Thomsen I.M.; Skovsgaard, J.P., Barklund, P. & Vasaitis, R. 2007. Svampesygdom er årsag til toptørre i ask. Skoven 10: 234- 236

PATHCAR - Virtual Centre of Advanced Research in Forest Pathology

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