Cryphonectria parasitica

Bark is infected through wounds. With time, ochre to orange pillows of pycnidia are formed at the site of infection from which arise conidia stalks. Then, sexual perithecia of the same colour to red are formed. Infected bark cracks and typical canker wounds are created. Under the bark there is an ochre-white fan-shaped syrrocium. The part of the branch or the trunk above the  infection site dies back. In the USA, the fungus was discovered for the first time in 1904 and by the 1950’s American chestnuts (Castanea dentata) were nearly extinct in almost 100% of the area of its autochthonous distribution. In Europe, the disease was found for the first time in 1925 in Belgium and in England, later it was also found in Central Europe – former Yugoslavia, Hungary, Czech Republic, Slovakia, and other countries. This fungus is one of the most serious pests of chestnuts tree in Europe.