On stems of beech extended flat bark lesions, sharply delimited from the living bark area and up to several meters in length; visible on the surface by numerous blackish-brown, up to 10mm thick and several cm long crusts (stroma) with roundish outline, later coalescing to long stripes; sexual fruiting bodies immersed in the crust, emerging with minute pores which give the surface a pointed appearance (hand lens!).
Affected tree species
This species is usually present in living tissues of various woody and herbaceous plant species without causing any symptoms (=endophytic stage. Only in European beech B. nummularia is able to destroy larger parts of the bark causing also discoloration and rot in the wood and finally the decline of the tree. This is triggered by dry and hot summer weather. in the past damage by this species was more common in mediterranean climates, meanwhile the disease is more widespread - a consequence of higher temperature and increase in drought stress in forests.
Curative measures Control not possible: as a prevention silvicultural measures to reduce drought stress or, in urban areas, irrigation.
Biscogniauxia nummularia>: stroma on the stem of a declining European beech
Biscogniauxia nummularia>: stroma on the stem of a dead and thrown European beech
Biscogniauxia nummularia>: stroma on the stem of a declining European beech, sharply delimited from the living bark
Biscogniauxia nummularia>: stroma, single and confluent
Biscogniauxia nummularia>: rot
Biscogniauxia nummularia>: single stroma, surface showing numerous pores of individual fruiting bodies