Artemisia vulgaris, Nieuwendam: germinating conidia

gall

mycelium amphigenous, mostly dense, white. Conidia in rather long chains, without fibrosin bodies. Foot-cell of conidiophore generally straight, 30-100 µm long, followed by 1-3 shorter cells. Appressoria nipple-shaped. cleistothecia amphigenous; appendages numerous, resembling ordinary hyphae, more or less brown, mostly shorter than the cleistothecial diameter. Up to 20 asci per cleistothecium, with generally 2 spores.

hostplants

Asteraceae, narrowly oligophagous:

Achillea abrotanoides, asiatica, aspleniifolia, biserrata, clypeolata, coarctata, collina, decolorans, distans & subsp. stricta, erba-rotta subsp. moschata, filipendulina, impatiens, ligustica, macrophylla, micrantha, millefolium & subsp. sudetica, nobilis, ptarmica, ptarmicifolia, salicifolia, tenuifolia; Anacyclus clavatus; Argyranthemum frutescens; Artemisia dracunculus; Chamaemelum nobile; Chrysanthemum x grandiflorum; Cota tinctoria, triumfettii; Cotulaaltissima, barbata, turbinata; Glebionis coronaria, segetum; Ismelia carinata; ? Leucanthemella serotina; Leucanthemum halleri, maximum, monspeliense, vulgare; Matricaria chamomilla, discoidea; Mauranthemum paludosum; Tanacetum balsamita, bipinnatum, coccineum, corymbosum & subsp. subcorymbosum, macrophyllum, partheniifolium, parthenium, vulgare; Tripleurospermum inodorum, maritimum.

synonyms

Erysiphe macrocarpa Speer, 1970.

notes

G. macrocarpus on Artemisia is difficult to separate from G. artemisiae. The most practical difference is in the colour of the appendages; almost hyaline in artemisiae, almost all brown in macrocarpus.

references

Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Jage, Klenke, Kruse ao (2016a), Jage, Klenke & Kummer (2010a) [cichoracearum p.p.], Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a, 2019a), Mieslerová, Kitner, Petřeková, ao (2020a).