Ustilago avenae | |
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Scientific classification | |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Ustilaginomycetes |
Order: | Ustilaginales |
Family: | Ustilaginaceae |
Genus: | Ustilago |
Species: | U. avenae |
Binomial name | |
Ustilago avenae (Pers.) Rostr., (1890) | |
Synonyms | |
Erysibe vera |
Ustilago avenae is a plant pathogen. Semiloose smut of oats can be found wherever oats are grown, as they are seldom treated with seed treatments. The level of treatment is low because oats command a lower sale price than other cereals and hence it is thought that treatment is uneconomic. Semiloose smut of oats, unlike loose smut of wheat and barley, can thus infect up to 80 per cent of a crop.
As with wheat and barley the grains of semiloose smut infected oat plants are completely replaced by the smut fungus. It is not evident until heads emerge and is very difficult to distinguish from covered smut.
As for loose smut of wheat and barley; however, the semiloose smut fungus is carried on the seed surface and not inside the embryo of the seed. The pathogen is activated when the infected seed germinates, and it extends toward the growing point of the plant.
Evident from flowering onwards when the plant begins to form the head, the fungus invades all of the young head tissue except for that of the rachis (backbone). Production of plant growth hormones by the fungus results in infected plant heads reaching flowering earlier than healthy heads.
The head produced by the infected plant contains black spore masses in place of the grain. The spores are loosely held and are easily spread by wind onto neighboring healthy plants. Because flowering of infected heads occurs earlier than healthy heads, production and release of spores occurs when the rest of the crop is flowering. Spores are blown by the wind into the flowers of the healthy plants. The spores enter the ovaries and become part of the developing grain. In this way, seed for the following year becomes contaminated.
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales.
Fusarium ear blight (FEB), is a fungal disease of cereals, including wheat, barley, oats, rye and triticale. FEB is caused by a range of Fusarium fungi, which infects the heads of the crop, reducing grain yield. The disease is often associated with contamination by mycotoxins produced by the fungi already when the crop is growing in the field. The disease can cause severe economic losses as contaminated grain cannot be sold for food or feed.
The smuts are multicellular fungi characterized by their large numbers of teliospores. The smuts get their name from a Germanic word for dirt because of their dark, thick-walled, and dust-like teliospores. They are mostly Ustilaginomycetes and can cause plant disease. The smuts are grouped with the other basidiomycetes because of their commonalities concerning sexual reproduction.
Sugarcane smut is a fungal disease of sugarcane caused by the fungus Sporisorium scitamineum. The disease is known as culmicolous, which describes the outgrowth of fungus of the stalk on the cane. It attacks several sugarcane species and has been reported to occur on a few other grass species as well, but not to a critical amount. The most recognizable characteristic of this disease is a black or gray growth that is referred to as a "smut whip". Resistance to sugarcane smut is the best course of action for management, but also the use of disease free seed is important. On smaller scale operations treatments using hot water and removing infected plants can be effective. The main mode of spore dispersal is the wind but the disease also spreads through the use of infected cuttings. Sugarcane smut is a devastating disease in sugarcane growing areas globally.
Take-all is a plant disease affecting the roots of grass and cereal plants in temperate climates caused by the fungus Gaeumannomyces graminis var. tritici. All varieties of wheat and barley are susceptible. It is an important disease in winter wheat in Western Europe particularly, and is favoured by conditions of intensive production and monoculture.
Common bunt, also known as stinking smut and covered smut, is a disease of both spring and winter wheats. It is caused by two very closely related fungi, Tilletia tritici and T. laevis.
Covered smut of barley is caused by the fungus Ustilago hordei. The disease is found worldwide and it is more extensively distributed than either loose smut or false loose smut.
Loose smut of barley is caused by Ustilago nuda. It is a disease that can destroy a large proportion of a barley crop. Loose smut replaces grain heads with smut, or masses of spores which infect the open flowers of healthy plants and grow into the seed, without showing any symptoms. Seeds appear healthy and only when they reach maturity the following season is it clear that they were infected. Systemic fungicides are the major control method for loose smut.
False loose smut is a fungal disease of barley caused by Ustilago nigra. This fungus is very similar to U. nuda, the cause of loose smut, and was first distinguished from it in 1932.
Fusarium culmorum is a fungal plant pathogen and the causal agent of seedling blight, foot rot, ear blight, stalk rot, common root rot and other diseases of cereals, grasses, and a wide variety of monocots and dicots. In coastal dunegrass, F. culmorum is a nonpathogenic symbiont conferring both salt and drought tolerance to the plant.
Alternaria triticina is a fungal plant pathogen that causes leaf blight on wheat. A. triticina is responsible for the largest leaf blight issue in wheat and also causes disease in other major cereal grain crops. It was first identified in India in 1962 and still causes significant yield loss to wheat crops on the Indian subcontinent. The disease is caused by a fungal pathogen and causes necrotic leaf lesions and in severe cases shriveling of the leaves.
Gibberella zeae, also known by the name of its anamorph Fusarium graminearum, is a fungal plant pathogen which causes fusarium head blight, a devastating disease on wheat and barley. The pathogen is responsible for billions of dollars in economic losses worldwide each year. Infection causes shifts in the amino acid composition of wheat, resulting in shriveled kernels and contaminating the remaining grain with mycotoxins, mainly deoxynivalenol, which inhibits protein biosynthesis; and zearalenone, an estrogenic mycotoxin. These toxins cause vomiting, liver damage, and reproductive defects in livestock, and are harmful to humans through contaminated food. Despite great efforts to find resistance genes against F. graminearum, no completely resistant variety is currently available. Research on the biology of F. graminearum is directed towards gaining insight into more details about the infection process and reveal weak spots in the life cycle of this pathogen to develop fungicides that can protect wheat from scab infection.
Crown rot of wheat is caused by the fungal pathogen Fusarium pseudograminearum. F. pseudograminearum is a member of the fungal phylum Ascomycota and is also known as Gibberella coronicola (teleomorph). It is a monoecious fungus, meaning it does not require another host other than wheat to complete its life cycle. Although F. pseudograminearum can produce both anamorphic and teleomorphic states, the teleomorph is usually not present for crown rot of wheat. This Fusarium species has, until recently, been considered to be the same as the species known as Fusarium graminearum due to many similar characteristics. One of the only differences between the two species is that F. pseudograminearum lacks its sexual stage on the wheat host.
Tilletia caries is a basidiomycete that causes common bunt of wheat. The common names of this disease are stinking bunt of wheat and stinking smut of wheat. This pathogen infects wheat, rye, and various other grasses. Tilletia caries is economically and agriculturally important because it reduces both the wheat yield and grain quality.
Urocystis agropyri is a fungal plant pathogen that causes flag smut on wheat.
Ascochyta pisi is a fungal plant pathogen that causes ascochyta blight on pea, causing lesions of stems, leaves, and pods. These same symptoms can also be caused by Ascochyta pinodes, and the two fungi are not easily distinguishable.
Sphacelotheca reiliana, also known as Sporisorium reilianum, is a species of biotrophic fungus in the family Microbotryaceae. It is a plant pathogen that infects maize and sorghum.
Gibberella fujikuroi is a fungal plant pathogen. It causes bakanae disease in rice seedlings.
Ustilago esculenta is a species of fungus in the Ustilaginaceae, a family of smut fungi. It is in the same genus as the fungi that cause corn smut, loose smut of barley, false loose smut, covered smut of barley, loose smut of oats, and other grass diseases. This species is pathogenic as well, attacking Manchurian wild rice, also known as Manchurian ricegrass, Asian wild rice, and wateroat. This grass is its only known host.