Biscogniauxia nummularia decline of European beech ("Fagus sylvatica") in Sicily and Calabria (Italy) has been linked to "B. nummularia" and experiments have suggested that this ascomycete plays a primary pathogenic role under certain environmental conditions. It typically causes strip‐cankering and general wood decay. Biscogniauxia nummularia Biscogniauxia nummularia is a plant pathogen in the family Xylariaceae, known as the beech tarcrust. The specific epithet is derived from the Latin "nummus" meaning a coin, referring to the often rounded and coin-like encrustations. The fruit body forms a thick and shiny black crust, on beech ("Fagus") bark and is found at all times of the
Stigmella hemargyrella Stigmella hemargyrella Stigmella hemargyrella is a moth of the Nepticulidae family. It is found in most of Europe, except Iceland, Norway, Finland, Portugal and most of the Baltic region. The moths (imago) are bivoltine flying from April to May and again from July to August and can be found resting on trunks. The wingspan is 5–6 mm. The egg can be laid on either side of the leaf and the pale yellowish-white larva feed, within a mine on "Fagus sylvatica" and "Fagus sylvatica orientalis". The mine is a sinuous gallery and at the early state is relatively narrow with a