Peronospora arthurii Farlow, 1883
on Clarkia, Oenothera

Oenothera spec., België, prov. Antwerpen, Mol © Carina Van Steenwinkel

underside infected leaf

conidiophore

conidia
gall
upperside of the leaves with yellow spots. Corresponding parts of the underside with a violet-grey down, consisting of erect conidiophores that apically several times are dichotomously branching, each branch ending in an egg-shaped or lemon-shaped conidium.
host plants
Onagraceae, oligophagous
Clarkia unguiculata; Oenothera biennis & var. pycnocarpa, glazioviana, parviflora, pycnocarpa.
notes
an invasive species in Europe.
references
Beenken & Senn-Irlet (2016a), Belbahri, Calmin, Pawlowski & Lefort (2005a), Brandenburger (1985a: 416), Göker, García-Blázquez, Voglmayr ao (2009a), Jage, Klenke, Kruse ao (2017a), Klenke & Scholler (2015a), Kruse (2014a, 2019a), Mułenko & Matejko Gosztyła (1997a), Mułenko, Piątek, Wołczańska ao (2010a), Müller & Kokeš (2008a), Ruszkiewicz (2000a), Ruszkiewicz-Michalska (2006a), Ruszkiewicz-Michalska & Michalski (2005a), Scheuer & Bechter (2012a), Thines & Choi (2016a), Thines, Telle, Ploch & Runge (2009b), Voglmayr (2003a).