Podosphaera senecionis Braun, 2012

on Asteraceae

Podosphaera senecionis on Jacobaea vulgaris

Jacobaea vulgaris, Belgium, prov. Antwerp, Meerhout 15.viii.2017 © Carina Van Steenwinkel

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Podosphaera senecionis: conidiophore

conidiophore

Podosphaera senecionis: conidia

conidia

Podosphaera senecionis on Senecio hercynicus

Senecio hercynicus, Belgium, prov. Liège, Büllingen, Vallée de la Holzwarche 19.viii.2017 © Carina Van Steenwinkel

Podosphaera senecionis on Senecio hercynicus

cleistothecia

Podosphaera senecionis: cleistothecium

cleistothecium

Podosphaera senecionis: ascus

ascus

Podosphaera senecionis on Senecio ovatus

Senecio ovatus, Amstelveen, Thijssepark

Podosphaera senecionis on Senecio ovatus

same leaf, underside: the fungus is amphigenous

Podosphaera senecionis on Senecio ovatus

not only the appendages of the cleistothecia, but also a large part of the mycelium is brown (“secundary mycelium”)

Podosphaera senecionis: cleistothecia

cleistothecia with appendages

Podosphaera senecionis: cleistothecium wall

part of the wall of a cleistothecium

Podosphaera senecionis: ascus

ascus

gall

mycelium amphigenous, also on the stems, white, later brown, persistent. Appressoria indistinct to ± nipple-shaped. Conidia in short chains, with fibrosin bodies. Foot-cell of conidiophore straight, 40-60 µm. Cleistothecia 70-95 µm, with a single ascus, containing (6-)8 spores. Appendages 4-15, sub-equatorial, 0.8-4 x the diameter; they are mycelioid, brown, mostly unbranched, septate or not.

hostplants

Asteracae, narrowly oligophagous

Jacobaea alpina, aquatica, erucifolia, maritima, paludosa, subalpina, vulgaris; Ligularia fischeri, sichotensis, sibirica; Packera heterophylla; Senecio duriaei, hercynicus, leucanthemifolius subsp. vernalis, lyratifolius, ovatus & subsp. stabianus, sarracenicus, sylvaticus, vulgaris; Tephroseris crispa, helenitis, integrifolia.

references

Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Ellis &ano; Ellis (1997a), Fraiture & Vanderweyen (2009a “P. fusca”), Jage, Kruse, Kummer ao (2013a), Kruse (2014a).

mod 18.viii.2018