Podosphaera leucotricha (Ellis & Everhart) Salmon, 1900
on woody Rosaceae
Malus domestica, Loenen (Gld) © Arnold Grosscurt: disfigured leaves.
The fungal down is hard to distinguish from the normal hair cover of the underside of the leaf.
Malus domestica, Dronten © Arnold Grosscurt: severe infection
mycelium amphigenous, often also on stems, well developed, white; infected leaves often disfigured. Appressoria indistinct to nipple-shaped. Conidia formed in chains, with fibrosin bodies, short-elliptic. Cleistothecia with a single ascus, containing eight spores. Appendages 3-7, above the equator, 3-7 x the diameter, standing as a bundle ± upright; they are more or less stiff, septate, unbranched or just below the tip with a few sort branches.
? Chaenomeles japonica; Cydonia oblonga; Malus domestica, floribunda, manshurica, x moerlandsii, x purpurea, sylvestris, toringo; Photinia x fraseri; Prunus cerasifera; Pyrus communis & subsp. pyraster, salicifolia; Spiraea.
Malus and Pyrus are the main hostplants
Blumer (1967a), Braun (1995a), Braun & Cook (2015a), Bresinsky (2016a), Buhr (1964b), Czerniawska (2001a), Ellis & Ellis (1997a), Gjaerum (1976a), Jage, Klenke, Kruse ao (2016a), Klenke & Scholler (2015a), Korytnianska & Popova (2012a), Kozłowska, Mułenko & Heluta (2015a), Kruse & Jage (2014a), Roskam (2009a), Ruszkiewicz-Michalska (2006a), Săvulescu & Rayss (1935a), Talgø, Sundheim, Gjærum ao (2010a).