Erysiphe prunastri de Candolle, 1815
on Prunus

Prunus spinosa, Belgium, prov. Limburg, Genk, de Maten © Carina Van Steenwinkel

infected leaf, upperside

same leaf, underside

cleistothecium

appendages

Prunus spinosa, België, prov. Limburg, Beringen,Mijn Terril © Carina Van Steenwinkel: cleistothecium infected by an unknown hyperparasite

hyperparsitic conidia
gall
mycelium amphigenous, thin. Cleistothecia with 5-18 asci, containing 5-7 spores. Appendages 20-30, equatorial, 1-2 x the diameter; they are stiff, hyaline, aseptate; apex somewhat enlarged, loosely or tightly circinate. Unripe cleistothecia moreover with 10-30 short, stiff bristle-like appendages on the upper half. Asci (5)10-15(18) with (4)5-7(8) spores.
hostplants
Rosaceae, monophagous
Prunus armeniaca, avium, cerasifera, domestica & subsp. insititia, mahaleb, padus, spinosa.
synonyms
Uncinula prunastri (de Candolle) Saccardo, 1882; U. prunastri var. armeniacae Viennot-Bourgin, 1968.
references
Ale-Agha, Boyle, Braun ao (2008a), Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Jage, Klenke, Kruse ao (2016a), Jage, Klenke & Kummer (2010a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Kruse (2014a).