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Remarks (public):For a complete description including images see www.cababstractsplus.org/dfb 
Remarks (internal):Readily distinguished from other bunts or covered smuts on Triticum by the apparently smooth-walled spores. Spores of Tilletia caries (CMI Descriptions 719) and T. controversa Kuhn are reticulate whilst in T. indica Mitra they are coarsely verrucose. There is less literature specifically referring to T. foetida than to T. caries but often the two species have not been distinguished. Tilletia foetida can be grown in culture in the dikaryotic state and teliospores as well as secondary sporidia can be produced. Soil factors interact with moisture in influencing spore germination (47, 791). The fungus is heterothallic and hybrids and dual infections of the fungus with T. caries are known to occur (54, 798). Pyrolysis Gas Liquid chromatography has been used to distinguish the two species (59, 3701). Low soil temperatures at sowing are known to predispose plants to infection as with T. caries (see CMI Descriptions 719). Control has been achieved primarily by the use of seed-applied chemicals and resistant varieties. Chlorinated hydrocarbons replaced organo-mercurial seed dressings (44, 1509) and more recently systemic fungicides have been used including carboxin (48, 1140), benomyl (51, 2371), thiabendazole (51, 1351). These are effective against strains showing tolerance of chlorinated hydrocarbon seed dressing (57, 2767). Biological control has been achieved using Bacillus spp. (56, 3988). Pathogen virulence is thought to be controlled by multiple factors (48, 423) and there are reports of new pathogenic races occurring (47, 3082; 55, 1196). Host resistance has been widely used in control and there is much literature on screening for resistance (often in conjunction with T. caries) (45, 787; 51, 2370; 52, 4015; 53, 2956; 54, 5384; 56, 4458; 59, 1206).
 
Description type:Non-original description 
Description:Tilletia foetida (Wallr.) Liro, Maanviljelys-taloudellinen Koelaitos, Vuosikirja 1915-1916: 27, 1920.
Erysibe foetida Wallr., Flora Cryptogamica Germaniae 2: 213, 1833.
Ustilago foetens Berk. & Curt., 1860.
Tilletia foetens (Berk. & Curt.) Schroter, 1877.
Tilletia foetens (Berk. & Curt.) Trel., 1884.
Tilletia laevis Kuhn, 1873.
Sori in the ovaries filling the grain with spores, partly concealed by the glumes, 4-8 mm long and of similar diameter to uninfected grain. Spore mass powdery, brownish-black, foetid, composed of spores and sterile cells. Sterile cells (intermixed with spores) globose, hyaline, thin-walled, smooth, 10-20 µm (mostly about 14 µm) diam.; few present in some collections. Spores without sheath, globose or subglobose to ovoid, olivaceous brown, 13-25 (mean 18,8) µm diam., walls smooth to shallowly pitted, 1,5-2 µm thick, often with a short mycelial fragment attached.
Hosts: On Triticum, Secale, Triticale, Hordeum, Agropyron, Elymus, Sitanion, Lolium.
Disease: Causes common bunt (stinking or covered smut) of wheat. Tilletia caries (CMI Descriptions 719) causes a virtually identical disease known by the same name. The seed contents inside the pericarp are converted to a mass of teliospores and the seed converted into a 'bunt ball' which ruptures on harvesting, releasing the black spores and the volatile compound trimethylamine which has a foul, fishy odour. Diseased plants are somewhat stunted and the heads of infected plants remain greener than those containing healthy grain and are more slender; the glumes of diseased spikelets are also spread apart.
Geographical distribution: Widely distributed in most countries where wheat is grown but less widespread than
T. caries and not apparently in UK (CMI Map 295, ed. 2, 1968).
Physiologic specialization: Exists in a number of races, similar to those of T. caries, based on differential reactions to wheat cultivars. Seventeen races based on reactions to 7 differential wheat varieties and arranged in 6 groups according to their reactions to 6 accepted resistance types were proposed for T. caries and T. foetida (41, 142). The spectrum of races has been investigated (usually in conjunction with those of T. caries) in Turkey (52, 3636), USSR (54, 408) and elsewhere. Thirty-nine pathogenic races of the bunt fungi (which include T. caries and T. controversa) based on combinations of 8 virulence genes are now recognised in the USA. Strains tolerant to HCB have been found in Australia (44, 2770).
Transmission: Spores are released when the grain is harvested and are dispersed by air to contaminate healthy grain and soil. Spores germinate in moist soil to produce a basidium and acicular basidiospores (primary sporidia). These fuse to produce a dikaryotic mycelium which may directly infect host seedling coleoptiles or produce further secondary sporidia.
Literature: Duran & Fischer, The Genus Tilletia, Washington State University 1961; Holton & Heald, Bunt or Stinking Smut of Wheat, Burgess, Minneapolis, 1941 (review of earlier literature); Fischer & Holton, Biology and Control of the Smut Fungi, Ronald Press, New York, 1957; Moore & Kuiper, Agricultural Gazette of New South Wales 85: 16-17, 1974 (recent control methods).

 
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