Apiognomonia errabunda (Roberge) von Höhnel, 1918
on woody plants
Tilia x europaea, Belgium, prov. Antwerp, Retie, Prinsenpark 29.vi.2018 © Carina Van Steenwinkel
underside of an infected leaf
like in A. veneta the leaf spots develop from the veins, but they are not angular.
same leaf, underside
characteristic also is the black discolouration of the petioles.
leaf spots with hypophyllous brown acervuli.
usually an asymptomatic endophytic leaf fungus. The anamorph causes in spring drying out of buds, die-off of young shoots, and large leaf spots with hypophyllous acervuli. Conidia 4-6 x 10-13 µm. On beech, where the fungus is very common, it may cause the death of the larvae of Hartigiola annulipes and Mikiola fagi (Wulf).
The teleomorph forms black perithecia with a long neck on fallen leaves and dead branches.
Gnomonia errabunda (Roberge) Auerswald, 1869; Discula umbrinella (Berkeley & Broome) Morelet, 1973; Apiognomonia tiliae (Rehm) von Höhnel 1920.
Vainio ao witnessed an outbreak of the fungus on Tilia cordata, causing large-scale defoliation, where it was striking that the petioles had turned blackish brown, while the leaf laminas remained green.
Brandenburger (1985a: 61, 64), Butin & Kehr (1999a), Ellis & Ellis (1997a), Kozłowska, Mułenko & Heluta (2015a), Melgarejo Nárdiz, García-Jiménez, Jordá Gutiérrez ao (2010a), Roskam (2009a), Ruszkiewicz-Michalska (2006a), Sogonov, Castlebury, Rossman ao (2008a), Vainio, Velmala, Salo ao (2017a), Wulf (1990).