Microbotryum dianthorum (Liro) H. Scholz & I. Scholz

Synonyms

Ustilago dianthi-arenarii Hammarl.
Ustilago dianthorum Liro
Ustilago violacea var. dianthorum (Liro) Durrieu & Zambett.
Ustilago superba Liro

Description

Sori in swollen anthers. Spore mass brownish violet, powdery. Infection systemic; all flowers of an infected plant affected; more rarely, infection semi-systemic and only flowers of certain branches affected.

Spores globose to slightly ellipsoidal, 6–9 (–11) µm diam., pale violet; wall reticulate; meshes rounded to regularly polygonal, to 1 µm diam.; muri 0.15–0.35 µm high, rather uneven, in median view with rounded edges.

Spore germination resulting in 4-celled (3 + 1) basidia producing lateral and terminal sessile basidiospores; basidial cells separating readily and continuing to produce basidiospores or, in nutrient media, yeast cultures.

Hosts
   
Host family: Caryophyllaceae
   
Host species: Dianthus caryophyllus L.

Distribution

Eradicated from Australia

Comments

Microbotryum violaceum (Pers.: Pers.) G.Deml & Oberw. is the name generally applied to the smut fungus that infects the anthers of plants in several genera (and over 100 species) in the Caryophyllaceae and related families. Recent molecular analysis has confirmed that M. violaceum is an assemblage of species (Lutz et al., 2005). Consequently, M. violaceum s. str. is rigorously applied to the species that infects anthers of Silene nutans L., the host of the type specimen (Vánky, 1998). Microbotryum dianthorum infects Dianthus.

Microbotryum dianthorum was first found in Australia causing carnation anther smut at a few nurseries in south-eastern Queensland in 1987. It was detected in carnations that had been imported as elite nursery stock from the Northern Hemisphere in late 1986. The pathogen was successfully eradicated and has not been detected in Australia since.