Podosphaera xanthii (Castagne) Braun & Shishkoff, 2000

polyphagous

Podosphaera xanthii on Bidens connatus

Bidens connatus, België, prov. Antwerp, Balen, de Most © Carina Van Steenwinkel

Podosphaera xanthii on Bidens connatus

detail of the underside of a leaf

Podosphaera xanthii: clestothecium

cleistothecium

Podosphaera xanthii: ascus

ascus (still unripe)

Podosphaera xanthii: conidium

conidium

gall

mycelium amphigenous, white. Appressoria indistinct to ± nipple-shaped, solitary. Conidia formed in chains, with fibrosin bodies. Cleistothecia containing a single ascus with usually 8 spores. A variable number of eventually brown, mycelioid appendages, 0.3 – 4 times the cleistothecial diameter.

The ascus apically has a small window, the “oculus”, by which the spores are ejected; it’s diameter is diagnostic: 15-25 µm.

hostplants

polyphagous

Abelmoschus; Adenostyles; Arctium lappa; Arnica montana; Bellidiastrum michelii; ? Bergia capensis; Benincasa; Bidens cernuus, connatus, frondosus, pilosus, radiatus, tripartitus; Cacalia; Calendula arvensis, maroccana, officinalis, stellata, suffruticosa; Centaurea scabiosa; Chondrilla juncea; Cirsium arvense, oleraceum; Citrullus lanatus; Coreopsis grandiflora, lanceolata, verticillata; Cosmos bipinnatus; Crotalaria; Cucumis sativus; Cucurbita maxima, moschata, pepo; Cyanus montanus, segetum; Dimorphotheca; Erechtites hieraciifolius; Gerbera; Glycine; Helianthus annuus; Hibiscus; Impatiens balsamina, parviflora; Lactuca muralis, saligna, serriola; Lagenaria siceraria; Luffa; Onopordum acanthium; Petasites albus, paradoxus; Phaseolus; Phlox paniculata; Physalis alkekengi; Polemonium; Prenanthes purpurea; Rhynchosia; Saintpaulia ionantha; Sanvitalia procumbens; Scrophularia; Sigesbeckia; Sonchus arvensis, oleraceus; Tanacetum vulgare; Tragopogon pratensis & subsp. orientalis; Verbena hybrida, officinalis; Vigna; Xanthium orientale & subsp. italicum + riparium, spinosum, strumarium.

synonyms

Sphaerotheca xanthii (Castagne) Junell, 1966; Sphaerotheca verbenae Săvulescu & Negru, 1953; Oidium saintpauliae Gorlenko, 1995.

notes

an inportat pest in cuurbit cultivation (Pérez-García ao, Ramos ao).

references

Ale-Agha, Boyle, Braun ao (2008a), Braun &anp; Cook (2012a), Braun, Shishkoff & Takamatsu (2001a), Bresinsky (2016a), Dietrich (2016b), Guatimosim, Pinto, Pereira ao (2015a), Jage, Klenke, Kruse ao (2016a), Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a), Kruse & Jage (2014a), Lee (2013a), Mayor (1973a), Pérez-García, Romero, Fernández-Ortuño ao (2009a), Ramos, Maruthachalam, McCreight & Garcia Estrada (2011a), Scheuer & Bechter (2012a), Schmid-Heckel (1985a “P. fuliginea”), Wołczańska (2008a).

19/04/2017

pub 25.v.2017 · mod 13.viii.2017