Platanus hispanica, Dronten © Arnold Grosscurt: a normal leaf, and two severely infested ones

Platanus spec., Arnhem, Spijkerkwartier, 2.xii.2021 © Kees van Oorde

cleistothecium with appendages

gall

mycelium amphigenous, dense, white, often persistent and causing malformations. Appressoria lobed, solitary or paired, sometimes one per cell, sometimes in groups of 2-6. Conidia solitary, short-elliptic, without fibrosin bodies. Foot cell of conidiophore basally generally ± flexuous. Cleistothecia with 3-6 asci, that contain 3-5 spores. Appendages 6-18, equatorial, 1-2 x the diameter; they are ± straight, brown at the base, 0-1 septate, unbranched; apices 3-5 times regularly forked.

host plants

Platanaceae, monophagous

Platanus acerifolia, hispanica, occidentalis, orientalis, racemosa.

Observed in Switzerland on Ailanthus altssima (Simaroubiaceae) (Beenken & Senn-Irlet).

synonyms

Microsphaera platani Howe, 1874.

notes

North American species that probably at the beginning of the 1960s has been introduced into southern Europe, and now is expanding rapidly over Europe (Scholler ao, 2012a).

Heluta a.o. found the cleistotheccial appendages much longer, up to three times the diameter.

references

Beenken & Senn-Irlet (2016a), Brandenburger (1985a), Braun (1997a), Braun & Cook (2012a), Bresinsky (2016a), Heluta, Korytnianska & Akata (2013a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Kruse (2019a), Leysen (2013a, 2017a), Mieslerová, Sedlářová, Michutová, ao (2020b), Negrean & Anastasiu (2006a), Scholler, Hemm & Lutz (2012a).