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Covered Smut (barley)
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. Symptoms Infected plants do not demonstrate symptoms until heading. Kernels of infected plants are replaced by masses of dark brown smut spores. Smutted heads are hard and compact. Infected plants may be stunted. Occasionally smut sori may also develop in leaf blades, where they appear as long streaks. Disease cycle Infection is seed-borne within the seed, the fungus penetrating the endosperm while the grain is being formed. Infected seeds give rise to systemically infected plants. The mycelium advances through the host tissue and becomes established behind the growing point. The spores are not readily blown or washed away by wind or rain. Spores are sticky in nature when present inside the membrane due to oily coating. At harvest, spore masses are broken up, scattering spores on grai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loose Smut (barley)
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. Hosts and symptoms The major symptom of loose smut is the "smutted" grain heads, which contain masses of black or brown spores where the grain would normally be. The spores completely replace the grain head so that there is no grain to be harvested on infected plants. It may be possible to identify infected plants in the field before they reach the flowering stage by looking for plants which are taller and more mature than the rest of the field. The fungus causes infected plants to grow slightly taller and mature slig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
False Loose Smut (barley)
False loose smut is a fungal disease of barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ... 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. Symptoms 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. Disease cycle The disease cycle of ''Ustilago nigra'' is similar to that of '' U. hordei'', the cause of covered smut of barley. The tel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the Embryo#Plant embryos, embryo and provides nutrition in the form of starch, though it can also contain Vegetable oil, oils and protein. This can make endosperm a source of nutrition in animal diet. For example, wheat endosperm is ground into flour for bread (the rest of the grain is included as well in whole wheat flour), while barley endosperm is the main source of sugars for beer production. Other examples of endosperm that forms the bulk of the edible portion are coconut "meat" and coconut "water", and Maize, corn. Some plants, such as certain orchids, lack endosperm in their seeds. Ancestral flowering plants have seeds with small embryos and abundant endosperm. In some modern flowering plants the embryo occupies most of the seed and the endosperm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycelium
Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates into a monokaryotic mycelium, which cannot reproduce sexually; when two compatible monokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form fruiting bodies such as mushrooms. A mycelium may be minute, forming a colony that is too small to see, or may grow to span thousands of acres as in '' Armillaria''. Through the mycelium, a fungus absorbs nutrients from its environment. It does this in a two-stage process. First, the hyphae secrete enzymes onto or into the food source, which break down biological polymers into smaller units such as monomers. These monomers are then absorbed into the mycelium by facilitated diffusion and ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spores
In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. They were thought to have appeared as early as the mid-late Ordovician period as an adaptation of early land plants. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoeboid infectious germs ("amoebulae") into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. In plants, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. In some rare cases, a diploid spore is also produced in some algae, or fungi. Under favourable conditions, the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teliospore
Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi (Rust (fungus), rusts and Smut (fungus), smuts), from which the basidium arises. Development They develop in ''telium, telia'' (sing. ''telium'' or ''teliosorus''). The telial host is the primary host in heteroecious rusts. The aecial host is the alternate host (look for pycnium, pycnia and Aecium, aecia). These terms apply when two hosts are required by a heteroecious rust fungus to complete its life cycle. Morphology Teliospores consist of one, two or more Dikaryon, dikaryote cells. Teliospores are often dark-coloured and thick-walled, especially in species where they overwinter (acting as chlamydospores). Two-celled teliospores formerly defined the genus ''Puccinia''. Here the wall is particularly thick at the tip of the terminal cell which extends into a beak in some species. Teliospores consist of Dikaryon, dikaryote cells. As the teliospore cells germinate, the cell nucleus, nuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathotype
A pathovar is a bacterial strain or set of strains with the same or similar characteristics, that is differentiated at infrasubspecific level from other strains of the same species or subspecies on the basis of distinctive pathogenicity to one or more plant hosts. Pathovars are named as a ternary or quaternary addition to the species binomial name, for example the bacterium that causes citrus canker ''Xanthomonas axonopodis'', has several pathovars with different host ranges, ''X. axonopodis'' pv. ''citri'' is one of them; the abbreviation 'pv.' means pathovar. The type strains of pathovars are pathotypes, which are distinguished from the types (holotype, neotype, etc.) of the species to which the pathovar belongs. See also * Infraspecific names in botany * Phytopathology * Trinomen In biology, trinomial nomenclature is the system of names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany. In zoology In zoolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxin
Carboxin is a narrow-spectrum fungicide used as a seed treatment in agriculture to protect crops from fungal diseases. It was first marketed by Uniroyal in 1969 using their brand name Vitavax. The compound is a benzanilide analog that combines a heterocyclic acid with aniline to give an inhibitor of succinate dehydrogenase (SDHI). Synthesis The first synthesis of carboxin was disclosed in patents filed by Uniroyal. : Ethyl 2-chloroacetoacetate is treated with 2-mercaptoethanol and base, followed by cyclisation and water removal under acidic conditions. The resultant ethyl ester of the 1,4-oxathiine heterocycle is then formed into an amide with aniline using standard conditions via the carboxylic acid and acid chloride. This gives carboxin in high overall yield. The compound has been crystallised in two polymorphic forms, which have equal biological activity. Mechanism of action The mechanism of action of carboxin was not established until several years after it was first reporte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tebuconazole
Tebuconazole is a triazole fungicide used agriculturally to treat plant pathogenic fungi. Environmental hazards Though the U.S. Food and Drug Administration considers this fungicide to be safe for humans, it may still pose a risk. It is listed as a possible carcinogen in the United States Environmental Protection Agency Office of Pesticide Programs carcinogen list with a rating of C (possible carcinogen). Its acute toxicity is moderate. According to the World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ... toxicity classification, it is listed as III, which means slightly hazardous. Due to the potential for endocrine-disrupting effects, tebuconazole was assessed by the Swedish Chemicals Agency as being potentially removed from the market by EU regulation 1107 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barley Diseases ...
This article is a list of diseases of barley (''Hordeum vulgare''). Bacterial and fungal diseases Nematodes, parasitic Virus, viroid and virus-like diseases Phytoplasma diseases Miscellaneous diseases and disorders Sources Barley Diseases, Queensland Government, AustraliaEPPO Standards, Guidelines on good plant protection - Barley, EuropeCommon Names of Diseases, The American Phytopathological Society, USUSDA ARS Fungal Database References Common Names of Diseases, The American Phytopathological Society{{DEFAULTSORT:List Of Barley Diseases * Barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungal Plant Pathogens And Diseases
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the traditional eukaryotic kingdoms, along with Animalia, Plantae, and either Protista or Protozoa and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''true fungi'' or ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
