Peronospora radii de Bary, 1864
on Asteraceae, Anthemideae
Tripleurospermum maritimum, Belgium, prov. Limburg, Herk-de-Stad, Schulensbroek © Carina Van Steenwinkel: the ligules stand unusually erect
the disc florets bear no down but are disfigured nonetheless
ligules with dark grey down
the tem is remarkably short and thick
terminal branches
the conidiophores arise from a basal disk-shaped organ
young conidia
mature conidia
Tripleurospermum maritimum, Belgium, prov. Limburg, Bree, de Luysen © Carina Van Steenwinkel<
the conidiophores are standing on a remarkable “attachment disc”
germinating conidium
gall
downy mildew on the leaves, but mainly on the disfigured flower heads, in particular the ligulate flowers. A down of erect, apically repeatedly dichotomously branching conidiophores produces a greyish-violet mass of conidia.
host plants
Asteraceae, narrowly oligophagous
Achillea ptarmica; Anthemis arvensis, cotula, ruthenica; Argyranthemum frutescens; Coleostephus myconis; Cota austrica; Glebionis coronaria, segetum; Leucanthemum vulgare; Matricaria chamomilla, discoidea; Tripleurospermum inodorum, maritimum
synonyms
Peronospora danica Gäumann, 1923.
references
Belbahri, Calmin, Pawlowski & Lefort (2005a), Ben-Ze’ev, Kenneth & Bonde (1987a), Brandenburger (1985a), Buhr (1964b), Chater, Woods, Stringer, ao (2020a), Constantinescu (1989), Doppelbaur, Huber & Poelt (1965a), Ellis & Ellis (1997a), García-Blázquez, Constantinescu, Tellería & Martín (2007a), Göker, García-Blázquez, Voglmayr ao (2009a), Gustavsson (1991a), Jage, Klenke, Kruse ao (2017a), Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2019a), Kruse, Thiel, Beenken ao (2018d), Müller & Kokeš (2008a), Roskam (2009a, 2019a), Rossman (2004a), Săvulescu (1948a), Thines & Choi (2016a), Tomasi (2014a), Voglmayr (2003a).