Erysiphe syringae-japonicae (Braun) Braun & Takamatsu, 2000
on Ligustrum, Syringa
Syringa vulgaris, Belgium, prov. Antwerp, Meerhout © Carina Van Steenwinkel
Amphigenous mildew bloom on the leaves. Conidia solitary, elliptic, without fibrosin bodies. Cleistothecia with 3-10 asci, containing (5-) 8 spores. Appendages 4-16, equatorial, about as long as the diameter; they are stiff, brown over at least the basal part, with maximally 1, basal septum. At their end they are several times dichotomously branched in a flat plane.
Perhaps German material from Acer opalus is also attributable to this species (Braun ao, 2009a).
Microsphaera aceris Bunkina, 1974.
when this Asiatic species for the first time appeared in Europe in 1990 the differences with E. syringae, on almost the same host spectre, seemed clear: syringae: asci with 3-6 spores and appendages hyaline or brownish only at the very base; syringae-japonicae: asci with 5-8 spores and appendages partly brown. However, later research has demonstrate a much larger variability of syringae, to the point that the two would have been synonymised if molecular data had not shown convincing differences. The only practical, albeit not definite, difference is that syringae (in Europe) forms cleistothecia only very rarely, while syringae-japonicae forms them profusely.
Akata & Heluta (2015a), Bacigálová & Marková (2006a), Beenken & Senn-Irlet (2016a), Braun, Ale-Agha, Bolay ao (2009a), Braun & Cook (2012a), Braun, Cunnington, Brielmaier-Liebetanz ao (2003a), Jage, Klenke, Kruse ao (2016a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2014a), Kruse (2019a), Kruse & Jage (2014a), Mułenko, Piątek, Wołczańska ao (2010a), Piątek (2003b, 2005b), Ruszkiewicz-Michalska & Michalski (2005a), Scheuer & Bechter (2012a), Takamatsu, Shiroya & Seko (2016a), Talgø, Sundheim, Gjærum ao (2010a).