Podosphaera erigerontis-canadensis (Léveillé) Braun & Liu, 2010
on Asteraceae
Erigeron canadensis, Belgium, prov. Antwerp, Meerhout 26.x.2016 © Carina Van Steenwinkel: cleistothecia with appendages
Taraxacum officinale, Belgium, prov. Antwerp, Oud-Turnhout, de Liereman, 9.ix.2016 © Carina Van Steenwinkel: cleistothecium with appendages
conidiophores
Taraxacum officinale, Belgium, prov. Limbourg, Bree, de Luysen, 9.vii.2017 © Carina Van Steenwinkel: conidiophore
Taraxacum officinale, België, prov. Antwerpen, Balen, Scheps © Carina Van Steenwinkel
a single ascus, and relatively few, large peridium cells are diagnostic for Podosphaera
ascus
conidiophore
gall
mycelium amphigenous, white, later brownish, often occupying the entire leaf. Conidia formed in chains, with fibrosin bodies. Cleistothecia often abundant, containing a single ascus with usually 8 spores. Usually less than 10 brown, flaccid appendages, 0.5 – 3 times the cleistothecial diameter.
The ascus apically has a small window, the “oculus”, by which the spores are ejected; it’s diameter is diagnostic: 8-15 µm.
host plants
Asteraceae, oligophagous
Adenostyles alliariae, alpina; Arnica montana; Chamaemelum nobile; Crepis aurea, biennis, capillaris, conyzifolia, foetida, micrantha, mollis & subsp. succisifolia, nicaeensis, paludosa, pontana, pulchra, pyrenaica, rubra, sancta, setosa, sibirica, sonchifolia, tectorum, vesicaria subsp. taraxacifolia; Erigeron acris subsp. politus, annuus & subsp. septentrionalis, bonariensis, borealis, canadensis, floribundus, philadelphicus, speciosus, sumatrensis; Hieracium bifidum, bupleuroides, dentatum, murorum, prenanthoides, racemosum; Hypochaeris radicata; Lapsana communis; Leontodon hispidus & subsp. hastilis, incanus; Matricaria chamomilla, discoidea; Picnomon acarna; Pilosella officinarum; Pulicaria dysenterica, vulgaris; Rhaponticum centauroides; Scorzoneroides autumnalis, helvetica, montana, pyrenaica, rilaensis; Serratula tinctoria; Solidago canadensis; Sonchus bulbosus; Taraxacum Erythrosperma, Palustria, arcticum, kok-saghysz, officinale; Tolpis coronopifolia, staticifolia; Tripleurospermum inodorum.
synonyms
Sphaerotheca erigerontis-canadensis (Léveillé) Junell, 1966.
references
Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Dynowska, Fiedorowicz & Kubiak (1999a), Doppelbaur & Doppelbaur (1973a “Sphaerotheca fuliginea”), Hafellner (1980a), Hagen (1941a), Jage, Klenke, Kruse ao (2016a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a, 2019a), Kruse & Jage (2014a), Leysen (2013a, 2017a), Mieslerová, Kitner, Petřeková, ao (2020a), Ruszkiewicz (2000a), Scheuer & Bechter (2012a), Scholler, Reinhard & Schubert (1996a [Sphaerotheca fusca on Taraxacum officinale]), Scholler & Schubert (1993a “Sphaerotheca fusca”).