Rhytisma acerinum (Persoon) Fries, 1819

on Acer

Rhytisma acerinum on Acer pseudoplatanus

Acer pseudoplatanus, Zwanenwater: later in summer the spots turn uniformly black

Rhytisma acerinum on Acer pseudoplatanus

Acer pseudoplatanus, SW Scotland, Girvan © Henry Harker: heavy infestation

Rhytisma acerinum: very young ink spots

Acer pseudoplatanus, Zeewolde, Harderbos © Hans Jonkman: the very first beginning of the “ink spots”

Rhytisma acerinum: mature stromata on Acer pseudoplatanus

Acer pseudoplatanus, Biddinghuizen, Spijkbos © Hans Jonkman: two mature stromata

gall

the black spot actually is a stroma. Embedded in the stroma are ascomata, that open by an elongated epiphyllous slit. The ascospores are needle-like.

host plants

Sapindaceae, monophagous

Acer opalus, platanoides, pseudoplatanus.

Tomasi (2014a) additionally mentions A. campestre.

synonyms

Melasmia acerina Léveillé, 1846; Rhytisma pseudoplatani Müller, 1913

notes

at intermediate levels of air pollution, the number of leaf spots is inversely proportional to the sulphur dioxide concentration; above a certain limit the fungus disappears altogether (Bevan & Greenhalgh, 1976a; Greenhalgh & Bevan, 1978a; Kosiba, 2007a; Skuhravá & Skuhravý, 1992b).

references

Abras, Fassotte, Chandelier & Cavelier (2008a), Bevan & Greenhalgh (1976a), Blumer (1946a), Buhr (196a), Doppelbaur & Doppelbaur (1973a), Ellis & Ellis (1997a), Greenhalgh & Bevan (1978a), Grimmett, Smith & Bärlocher (2012a), Jage, Klenke, Kruse ao (2016a), Jage, Kruse, Kummer ao (2013a), Jage, Scholler & Klenke (2010a), Kosiba (2007a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a), Negrean (1995a), Roldan Garrigós & Honrubia García (1992a), Roques, Cleary, Matsiakh & Eschem (2017a), Roskam (2009a), Ruszkiewicz-Michalska (2006a), Skuhravá & Skuhravý (1992b), Tomasi (2003a, 2012a, 2014a).

mod 4.iv.2019