Viburnum lantana, Belgium, prov. Antwerp, Balen, de Vennen © Carina Van Steenwinkel

underside of the leaf, with large numbers of cleistothecia

cleistothecium

gall

Mycelium amphigenous, but best developed at the underside of the leaf. Conidia solitary, elliptic, without fibrosin bodies. Cleistothecia 65-90 µm, with 2-4 asci containing 4-7 spores. Appendages 3-8, equatorial, 1-1.5 x the diameter; they are stiff, extending, brown at the base, have 0-1 basal septa, the cell wall is smooth or rough; apically they are ± 4-5 times bifurcated in quick succession.

According to Klenke & Scholler conidia are formed regularly, and the cleistothecia are amphigenous.

host plants

Adoxaceae, monophagous

Viburnum burejaeticum, carlesii, ?glomeratum, lantana, tinus.

synonyms

Microsphaera hedwigii (Léveillé) Saccardo, 1882.

notes

Not on Viburnum opulus; see Erysiphe viburni for that host plant.

references

Ale-Agha, Boyle, Braun ao (2008a), Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Jage, Klenke & Kummer (2010a), Jage, Scholler & Klenke (2010a), Klenke & Scholler (2015a), Kruse (2014a, 2019a), Kruse & Jage (2014a), Ruszkiewicz-Michalska & Michalski (2005a), Sucharzewska, Dynowska, Kubiak ao (2012b), Świderska, Wołczańska, Kozłowska ao (2005a).