Tilletia trabutii Jacz.

Synonyms

Tilletia hordeina Ranoj.

Description

Sori in swollen ovaries filled with semi-agglutinated to powdery dark reddish brown foetid spore masses. Infection systemic.

Spores globose, subglobose to broadly ellipsoidal, 19–23 × 19–22.5 µm, yellowish brown; wall deeply reticulate, (3–) 4–5 (–6) meshes per spore diameter; areolae polygonal, usually rather large, regular (occasionally some spores with irregular to cerebriform ornamentation), 3–5 µm wide; muri 1.5–2.0 µm high, subacute to acute, spiniform, 16–24 on the equatorial circumference, a hyaline gelatinous sheath present.

Sterile cells globose, subglobose or ellipsoidal, smaller than the spores, 10–16 × 9–16 µm, subhyaline; wall 1–3 µm thick, smooth.

Hosts
   
Host family: Poaceae
   
Host species: Hordeum murinum L.
Hordeum leporinum Link

Distribution

States & Territories: NSW, SA, TAS, VIC

Comments

The smut on barley grasses (Critesion spp., previously Hordeum leporinum, H. murinum and H. maritimum) in Australia and elsewhere has been known for many years as Tilletia contraversa J.G.Kühn [type on Triticum repens L., Germany], which causes dwarf bunt of winter wheat in Europe and North America. However, dwarf bunt of wheat has never been seen in Australia. Its absence is possibly due to the fact that optimal conditions for infection of wheat by T. contraversa occur during winter under extended snow cover, a climatic phenomenon not experienced by Australian winter wheat crops.

The absence of T. contraversa on wheat in Australia raised the issue as to whether isolates of T. contraversa on barley grasses were conspecific with those causing dwarf bunt of wheat (Pascoe et al., 2005a). Pascoe et al. (2005a) used molecular and morphological criteria to show that the smut on Critesion in Australia was not conspecific with T. contraversa and that its correct name was T. trabutii.