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Groundnut Rosette Virus
''Groundnut rosette virus'' (GRV) is a peanut pathogenic virus found in Sub-Saharan Africa. It is transmitted between plants by insect vectors such as the groundnut aphid (''Aphis craccivora''). History The groundnut (''Arachis hypogaea'') originated in South America where it has long been domesticated. More recently it has been cultivated in other parts of the world and is an important subsistence crop in Sub-Saharan Africa. Groundnut rosette virus was first described in Africa in 1907 and causes serious damage to groundnut crops on that continent. In 1939 it was reported to infect 80 to 90% of plants in the Belgian Congo causing major losses in yield. The virus can spread rapidly through a crop. In a study in Tanzania, the first affected plants were seen six days after the first aphids were observed. Aphid numbers built up rapidly and the disease increased tenfold in two weeks with 65% of the crop plants affected three weeks later. Symptoms Research has shown that plants infe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peanut
The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics, important to both small and large commercial producers. It is classified as both a grain legume and, due to its high oil content, an oil crop. World annual production of shelled peanuts was 44 million tonnes in 2016, led by China with 38% of the world total. Atypically among legume crop plants, peanut pods develop underground (geocarpy) rather than above ground. With this characteristic in mind, the botanist Carl Linnaeus gave peanuts the specific epithet ''hypogaea'', which means "under the earth." The peanut belongs to the botanical family Fabaceae (or Leguminosae), commonly known as the legume, bean, or pea family. Like most other legumes, peanuts harbor symbiotic nitrogen-fixing bacteria in root nodules. The capacity to fix nitrogen means peanuts require less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-Saharan Africa
Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sovereign states and dependent territories in Africa, African countries and territories that are situated fully in that specified region, the term may also include polities that only have part of their territory located in that region, per the definition of the United Nations (UN). This is considered a non-standardized geographical region with the number of countries included varying from 46 to 48 depending on the organization describing the region (e.g. UN, WHO, World Bank, etc.). The Regions of the African Union, African Union uses a different regional breakdown, recognizing all 55 member states on the continent - grouping them into 5 distinct and standard regions. The term serves as a grouping counterpart to North Africa, which is instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector (epidemiology)
In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito. Arthropods Arthropods form a major group of pathogen vectors with mosquitoes, flies, sand flies, lice, fleas, ticks, and mites transmitting a huge number of pathogens. Many such vectors are haematophagous, which feed on blood at some or all stages of their lives. When the insects feed on blood, the pathogen enters the blood stream of the host. This can happen in different ways. The '' Anopheles'' mosquito, a vector for malaria, filariasis, and various arthropod-borne-viruses ( arboviruses), inserts its delicate mouthpart under the skin and feeds on its host's blood. The parasites the mosquito carries are usually located in its sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphis Craccivora
''Aphis craccivora'', variously known as the cowpea aphid, groundnut aphid or black legume aphid, is a true bug in the family ''Aphididae''. Originally of probable Palearctic origin, it is now an invasive species of cosmopolitan distribution. Description ''Aphis craccivora'' is a small species of aphid. The female has a glossy black or dark brown body with a prominent cauda (tail-like protrusion), and legs in some shade of brown or yellow. The antennae have six segments and these and the limb segments, cauda and cornicles are pale proximally (close to the body) and dark distally (further from the body). The adults do not have wax on their dorsal surface but the nymphs are lightly dusted with wax. Winged females are up to long and have cross-barring on the abdomen. Wingless females are a little smaller. Distribution ''Aphis craccivora'' is believed to be Palearctic in origin but has expanded its range so that now it is near cosmopolitan. In recent years its range has extend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAB International
CABI (legally CAB International, formerly Commonwealth Agricultural Bureaux) is a nonprofit intergovernmental development and information organisation focusing primarily on agricultural and environmental issues in the developing world, and the creation, curation, and dissemination of scientific knowledge. Overview CABI is an international not-for-profit organisation. Their work is delivered through teams of CABI scientists and key partners working in over 40 countries across the world. CABI states its mission as "improving people’s lives worldwide by solving problems in agriculture and the environment". These problems include loss of crops caused by pests and diseases, invasive weeds and pests that damage farm production and biodiversity, and lack of global access to scientific research. Funding CABI states that only 3% of its revenue comes from core funding. Donors listed in the company's 2014 financial report include the UK's Department for International Development (£ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite (biology)
A satellite is a subviral agent that depends on the coinfection of a host cell with a helper virus for its replication. Satellites can be divided into two major classes: satellite viruses and satellite nucleic acids. Satellite viruses, which are most commonly associated with plants, are also found in mammals, arthropods, and bacteria. They encode structural proteins to enclose their genetic material, which are therefore distinct from the structural proteins of their helper viruses. Satellite nucleic acids, in contrast, do not encode their own structural proteins, but instead are encapsulated by proteins encoded by their helper viruses. The genomes of satellites range upward from 359 nucleotides in length for satellite tobacco ringspot virus RNA (STobRV). Most viruses have the capability to use host enzymes or their own replication machinery to independently replicate their own viral RNA. Satellites, in contrast, are completely dependent on a helper virus for replication. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-infection
Coinfection is the simultaneous infection of a host by multiple pathogen species. In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles. An example is the coinfection of liver cells with hepatitis B virus and hepatitis D virus, which can arise incrementally by initial infection followed by superinfection. Global prevalence or incidence of coinfection among humans is unknown, but it is thought to be commonplace, sometimes more common than single infection. Coinfection with helminths affects around 800 million people worldwide. Coinfection is of particular human health importance because pathogen species can interact within the host. The net effect of coinfection on human health is thought to be negative. Interactions can have either positive or negative effects on other parasites. Under positive parasite interactions, disease transmission and progression are enhanced and this is also known as syndemism. Negative parasite inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus Classification
Virus classification is the process of naming viruses and placing them into a taxonomic system similar to the classification systems used for cellular organisms. Viruses are classified by phenotypic characteristics, such as morphology, nucleic acid type, mode of replication, host organisms, and the type of disease they cause. The formal taxonomic classification of viruses is the responsibility of the International Committee on Taxonomy of Viruses (ICTV) system, although the Baltimore classification system can be used to place viruses into one of seven groups based on their manner of mRNA synthesis. Specific naming conventions and further classification guidelines are set out by the ICTV. A catalogue of all the world's known viruses has been proposed and, in 2013, some preliminary efforts were underway. Definitions Species definition Species form the basis for any biological classification system. Before 1982, it was thought that viruses could not be made to fit Ernst May ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorosis
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates through photosynthesis and may die unless the cause of its chlorophyll insufficiency is treated and this may lead to a plant diseases called rusts, although some chlorotic plants, such as the albino ''Arabidopsis thaliana'' mutant ''ppi2'', are viable if supplied with exogenous sucrose. The word ''chlorosis'' is derived from the Greek ''khloros'' meaning "greenish-yellow", "pale green", "pale", "pallid", or "fresh". In viticulture, the most common symptom of poor nutrition in grapevines is the yellowing of grape leaves caused by chlorosis and the subsequent loss of chlorophyll. This is often seen in vineyard soils that are high in limestone such as the Italian wine region of Barolo in the Piedmont, the Spanish w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peanut Clump Virus
''Peanut clump virus'' (PCV) is a plant pathogenic virus. It is assigned to the genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ... '' Pecluvirus''. References External links ICTVdB - The Universal Virus Database: Peanut clump virus* Viral plant pathogens and diseases Virgaviridae {{Virus-plant-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemic
An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time. Epidemics of infectious diseases are generally caused by several factors including a significant change in the ecology of the areal population (e.g., increased stress maybe additional reason or increase in the density of a vector species), the introduction of an emerging pathogen to an areal population (by movement of pathogen or host) or an unexpected genetic change that is in the pathogen reservoir. Generally, epidemics concerns with the patterns of infectious disease spread. An epidemic may occur when host immunity to either an established pathogen or newly emerging novel pathogen is suddenly reduced below that found in the endemic equilibrium and the transmission threshold is exceeded. For example, in meningococcal infections, an attack rate in excess of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
