Plant Parasites of Europe

leafminers, galls and fungi

Sawadaea bicornis

Sawadaea bicornis (Wallroth) Homma, 1937

on Acer

Sawadaea bicornis on Acer campestre

Acer campestre, Biddinghuizen, Spijk- en Bremerbergbos 4.ix.2018 © Hans Jonkman

Sawadaea bicornis: conidia chains

Acer campestre, Nieuwendam: spring aspect, with conidia chains

Sawadaea bicornis: forming green islands in Acer campestre

Acer campestre, Nieuwendam, autumn: the mildew patches are situated at the underside of the green islands.

Sawadaea bicornis: macroconidia

Acer campestre, Nieuwendam: macroconidia

Sawadaea bicornis: cleistothecium


Sawadaea bicornis: appendages


Sawadaea bicornis: immaturee ascus

immature ascus

Sawadaea bicornis: conidiophore


Sawadaea bicornis: cleistothecium

Acer pseudoplatanus, Belgium, prov. Antwerp, Meerhout © Carina Van Steenwinkel

Sawadaea bicornis: cleistothecium and asci

released asci

Sawadaea bicornis: appendages


Sawadaea bicornis: ascus


Sawadaea bicornis on Acer platanoides

Acer platanoides, Castricum

Sawadaea bicornis: cleistothecium


Sawadaea bicornis: cleistothecium

stronger magnification


Mycelium mostly hypophyllous, rather thin. Conidia formed in chains, variable in size (micro- and macro-conidia), with fibrosin bodies. Cleistothecia hypophyllous, with 35-100 short, stiff appendages, most of them forked once of twice, the tips with a small hook.

host plants

Sapindaceae, monophagous

Acer campestre, circinatum, ginnala, heldreichii, macrophyllum, monspessulanum, negundo, obtusatum, opalus, pensylvanicum, platanoides, pseudoplatanus, rubrum, saccharum, saccharinum, semenovii, tataricum.

Very common on Acer campestre. Occasionally on Aesculus hippocastanum.


Uncinula aceris (de Candolle) Saccardo, 1882; U. bicornis (Wallrorth) Léveillé, 1851; Oidium aceris Rabenhorst, 1854.


Abras, Fassotte, Chandelier & Cavelier (2008a), Ale-Agha, Boyle, Braun ao (2008a), Blumer (1946a), Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Czerniawska (2001a), Czerniawska, Madej, Adamska ao (2000a), Dynowska, Fiedorowicz & Kubiak (1999a), Ellis & Ellis (1997a), Jage, Klenke, Kruse ao (2016a), Jage, Klenke & Kummer (2010a), Jage, Kruse, Kummer ao (2013a), Jage, Scholler & Klenke (2010a), Klenke & Scholler (2015a), Korytnianska & Popova (2012a), Kruse (2014a, 2019a), Kruse & Jage (2014a), Roques, Cleary, Matsiakh & Eschem (2017a), Scheuer & Bechter (2012a), Sucharzewska, Dynowska, Kubiak ao (2012b), Talgø, Sundheim, Gjærum ao (2010a), Tóth (1994a), Unamuno (1943a).

Last modified 12.vii.2019