False loose smut | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Ustilaginomycetes |
Order: | Ustilaginales |
Family: | Ustilaginaceae |
Genus: | Ustilago |
Species: | U. nigra |
Binomial name | |
Ustilago nigra | |
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. [2]
The disease is not apparent until heading, at which time, smutted heads emerge slightly earlier than healthy heads. At first, each smutted head is covered by a delicate, paperlike, grayish membrane. These membranes break shortly after the smutted heads have emerged and expose a dark brown to black, powdery mass of spores. These spores are easily dislodged, leaving only the bare rachis. [3]
The disease cycle of Ustilago nigra is similar to that of U. hordei , the cause of covered smut of barley. The teliospores survive on the surface or in the soil. In some cases, the teliospores that are deposited under the hull, may germinate immediately. The mycelium then grows into the lower layers of the seed and then remains dormant until seed germination.
Infection of seedling occurs between germination and emergence. Infection can occur from seed-borne teliospores or by teliospores residing in the soil. Relatively dry soil at temperatures of 15–21 °C, are most favorable for infection. The invading mycelium becomes established within the growing point. As the plant enters the boot stage, the mycelium grows rapidly into the floral tissue which is converted to masses of black teliospores. Teliospores are disseminated by wind or during combining. The teliospores may remain viable for several spores. [2]
The incidence of false loose smut can be reduced by using clean seed, treated seed and resistant cultivars.
Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
Corn smut is a plant disease caused by the pathogenic fungus Mycosarcoma maydis. One of several cereal crop pathogens called smut, the fungus forms galls on all above-ground parts of corn species such as maize and teosinte. The infected corn is edible; in Mexico, it is considered a delicacy, called huitlacoche, often eaten as a filling in quesadillas and other tortilla-based dishes, as well as in soups.
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 comprise seven of the 15 orders of the subphylum. Most described smuts belong to two orders, Ustilaginales and Tilletiales. The smuts are normally grouped with the other basidiomycetes because of their commonalities concerning sexual reproduction.
Karnal bunt is a fungal disease of wheat, durum wheat, and triticale. The smut fungus Tilletia indica, a basidiomycete, invades the kernels and obtains nutrients from the endosperm, leaving behind waste products with a disagreeable odor that makes bunted kernels too unpalatable for use in flour or pasta. While Karnal bunt generally does not lead to devastating crop losses, it has the potential to dramatically decrease yield, and poses additional economic concerns through quarantines which limit the export of suspected infectious wheat products from certain areas, including the U.S. Several chemical control methods exist for Karnal bunt of wheat, but much work remains to be done in identifying resistant host varieties.
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.
Scald is common disease of barley in temperate regions. It is caused by the fungus Rhynchosporium commune and can cause significant yield losses in cooler, wet seasons.
Common bunt, also known as hill bunt, Indian bunt, European bunt, stinking smut or 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.
Spot blotch is a disease of barley caused by Cochliobolus sativus. The disease is found everywhere that barley is grown, but only causes significant yield losses in warm, humid climates.
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.
Gibberella zeae, also known by the name of its anamorph Fusarium graminearum, is a fungal plant pathogen which causes fusarium head blight (FHB), 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 (DON), 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.
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. T. 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.
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.
Sporisorium sorghi, commonly known as sorghum smut, is a plant pathogen that belongs to the Ustilaginaceae family. This fungus is the causative agent of covered kernel smut disease and infects sorghum plants all around the world such as Sorghum bicolor (sorghum), S. sudanense, S. halepense and Sorghumvulgare var. technichum (broomcorn). Ineffective control of S. sorghi can have serious economic and ecological implications.
Ustilaginoidea virens, perfect sexual stage Villosiclava virens, is a plant pathogen which causes the disease "false smut" of rice which reduces both grain yield and grain quality. The disease occurs in more than 40 countries, especially in the rice producing countries of Asia. but also in the U.S. As the common name suggests, it is not a true smut (fungus), but an ascomycete. False smut does not replace all or part of the kernel with a mass of black spores, rather sori form erupting through the palea and lemma forming a ball of mycelia, the outermost layers are spore-producing. Infected rice kernels are always destroyed by the disease.
Sporisorium reilianum Langdon & Full., (1978), previously known as Sphacelotheca reiliana, and Sporisorium reilianum, is a species of biotrophic fungus in the family Ustilaginaceae. It is a plant pathogen that infects maize and sorghum.
Tilletia horrida, rice kernel smut, caryopsis smut, black smut, or grain smut, is a fungal rice disease believed to only affect the Oryza genus. It presents as a partial bunt.
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.
Thecaphora frezzii, commonly referred to as peanut smut, is a species of smut fungus of the genus Thecaphora and the family Glomosporiaceae. It is a basidiomycete fungus that infects peanut plants. It is currently only found in South America, more specifically in Argentinian peanut farms.