Holcus mollis, Denekamp; lg. Singraven, 24.iv.2014:: advanced infection

Elytrigia repens, Nieuwendam, 18.vi.2013: upperside of a leaf

detail, enlarged

the conidia are formed in a string

cleistothecium

opened cleistothecium, with still unripe asci

Holcus mollis, Denekamp; lg. Singraven: characteristic for Blumeria is a swelling at the base of the conidia chain; at right three mature conidia

gall

mycelium amphigenous, also on the stems and in the inflorescence, effuse, persistent, ultimately a greyish brown felt. Appressoria nipple-shaped, single or paired. Conidia formed in chains, elliptic, without fibrosin bodies. Foot cell of conidiophore with a bulbous swelling. Cleistothecia depressed, with 6-30 asci, generally containing 8 spores. Appendages in varying number, sub-equatorial, mostly shorter than the diameter; they are mycelioid, simple, septate.

hostplants

Poaceae, broadly oligophagous

Achnatherum calamagrostis; Aegilops crassa, cylindrica, tauschii, ventricosa; Aegilotrichum triticoides; Agropyron cristatum; Agrostis alpina, canina, capillaris, castellana, gigantea, stolonifera; Aira caryophyllea, elegantissima; Alopecurus aequalis, geniculatus, myosuroides, pratensis, rendlei; Ammochloa; Andropogon; Anisantha madritensis, rigida, sterilis, tectorum; Anthoxanthum aristatum, odoratum, ovatum; Apera interrupta, spica-venti; Aristavena setacea; Arrhenatherum elatius; Avena barbata, brevis, fatua, nuda, sativa & subsp. chinensis, sterilis, strigosa; Avenella flexuosa; Avenula pubescens; Beckmannia; Bellardiochloa variegata; Boissiera, Bouteloua; Brachypodium pinnatum, sylvaticum; Briza maxima, media, minor; Bromopsis benekenii, erecta, inermis, ramosa; Bromus arvensis, commutatus, grossus, hordeaceus, japonicus, lanceolatus, racemosus, secalinus, squarrosus; Calamagrostis arundinacea, canescens, epigeios, rivalis, villosa; Catabrosa aquatica; Catapodium rigidum; Ceratochloa carinata, cathartica; Cinna; Cleistogenes; Coleanthus subtilis; Cornucopiae; Corynephorus canescens; Crithopsis; Cutandia; Cynodon dactylon; Cynosurus cristatus, echinatus; Dactylis glomerata & subsp. lobata; Danthonia alpina, decumbens; Dasypyrum; Deschampsia cespitosa; Digitaria sanguinalis; Dinebra; Drymochloa sylvatica; Echinaria; Elymus caninus; Elytrigia elongata, intermedia, juncea & subsp. boreoatlantica, repens; Eragrostis cilianensis, tef; Eremopoa; Eremopyrum; Festuca alpina, heterophylla, ovina, rubra, stricta subsp. trachyphylla; Gastridium; Gaudinia fragilis; Glyceria maxima; Helictochloa bromoides, planiculmis, pratensis; Helictotrichon desertorum; Hierochloe australis, odorata; Holcus lanatus, mollis; Hordelymus europaeus; Hordeum bulbosum, marinum, murinum, vulgare & subsp. spontaneum; Koeleria glauca, macrantha, pyramidata; Lagurus ovatus; Lamarckia aurea; Leersia; Leymus arenarius; Lolium multiflorum, perenne, remotum, temulentum; Macrochloa tenacissima; Melica ciliata, nutans, persica, trassilvanica, uniflora; Mibora minima; Micropyrum tenellum; Milium effusum; Molinia caerulea; Muhlenbergia; Nardus stricta; Ochlopoa annua; Oplismenus; Panicum virgatum; Parapholis; Pennisetum villosum; Phalaris; Phleum alpinum, hirsutum, paniculatum, phleoides, pratense; Phragmites australis; Phyllostachys; Pilgerochloa; Piptatherum paradoxum; Poa alpina, angutifolia, bulbosa, cenisia, chaixii, compressa, glauca, minor, molinerii, nemoralis, palustris, pratensis, pumila, remota, trivialis, versicolor; Polypogon monspeliensis; Psathyrostachys juncea; Psilurus incurvus; Puccinellia distans & subsp. limosa, maritima; Rostraria cristata; Saccharum; Schedonorus arundinaceus, giganteus, pratensis; Schismus; Sclerochloa dura; Secale cereale, strictum, vavilovii; Sesleria autumnalis, caerulea, heufleriana, latifolia, rigida; Setaria adhaerens, italica; Sphenopus; Sporobolus; Stipa barbata; Taeniatherium; Tripidium; Trisetum distichophyllum, flavescens, spicatum; Triticale, Triticosecale blaringhemii; Triticum aestivum & subsp. spelta; Vulpia bromoides, geniculata, myuros, unilateralis.

synonyms

Erysiphe graminis de Candolle, 1815; Oidium monilioides (Nees) Link, 1924 (anamorph).

notes

Until recently, in Europe, the only powdery mildew on grasses. Liu, Braun, Takamatsu, ao (2021a) recognised several species (listed below), several new and probably soon more will follow. Their relations with (groups of) host species are not clear-cut, and provisionally it is advisable to name grass mildews B. graminis s.l.

1. Blumeria americana Liu, 2021
2. Blumeria avenae Liu & Hambleton, 2021
3. Blumeria bromi-cathartici Takamatsu & Liu, 2021
4. Blumeria bulbigera (Bonorden) Liu & Braun, 2021
5. Blumeria dactylidis Liu & Hambleton, 2021
6. Blumeria graminicola Liu & Hambleton, 2021
7. Blumeria graminis (de Candolle) Speer, 1975
8. Blumeria hordei Liu & Hambleton, 2021

references

Bahçecioğlu, Kabaktepe & Yildiz (2006a), Bahçecioğlu & Yildiz (2005a), Blumer (1946a, 1967a), Brandenburger (1985a), Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Czerniawska (2001a), Czerniawska, Madej, Adamska ao (2000a), Doppelbaur & Doppelbaur (1973a), Dynowska, Fiedorowicz & Kubiak (1999a), Ellis & Ellis (1997a), Heluta, Hayova, Tykhonenko ao (2010a), Jage, Klenke, Kruse ao (2016a), Jage, Klenke & Kummer (2010a), Jage, Kruse, Kummer ao (2013a), Jage, Scholler & Klenke (2010a), Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a, 2019a), Kruse & Jage (2014a), Kruse, Thiel, Brodtbeck ao (2017a), Kummer (2009a, 2012a), Leysen (2017a), Liu, Braun, Takamatsu, ao (2021a), Mayor (1971a), Melgarejo Nárdiz, García-Jiménez, Jordá Gutiérrez ao (2010a), Mułenko, Sałata & Wołczańska (1995a), Negrean (1996b), Özaslan, Hüseyin & Erdogdu (2014a), Negrean & Denchev (2004a), Oberhaensli, Parlange, Buchmann ao, (2011a), Porta-Puglia & Mifsud (2006a), Ruszkiewicz-Michalska (2006a), Ruszkiewicz-Michalska & Michalski (2005a), Scheuer & Bechter (2012a), Scholler, Reinhard & Schubert (1996a), Speer (1973a), Unamuno (1941a, 1942a, 1943a).