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Beet Leafhopper
The beet leafhopper (''Circulifer tenellus''), also sometimes known as ''Neoaliturus tenellus'', is a species of leafhopper which belongs to the family Cicadellidae in the order Hemiptera. Morphology A lot of morphological diversity has been reported among populations of the beet leafhopper in the United States. Morphological descriptions of two different populations of beet leafhoppers from California and Mexico are presented here. The leaf hopper is described as a small insect, in length, that is often greenish yellow, tan or olive in colour. The leaf hopper may have darker markings on its wings, pronotum, abdomen and head if it has developed during colder temperatures. The general shape of the body has been described as "wedge shaped" with the body tapering off at the posterior end of the insect. The head of the insect is wider than the pronotum with distinct eyes and a curved anterior margin. The mouth parts, like that of all hemipterans, have stylets used for penetrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Fuller Baker
Charles Fuller Baker (March 22, 1872, Lansing, Michigan – July 22, 1927, Manila) was an American entomologist, botanist, agronomist and plant collector. He was the second dean of the University of the Philippines College of Agriculture, now the University of the Philippines Los Baños. References External links ;Smithsonian Institution Archives Smithsonian Libraries and Archives is an institutional archives and library system comprising 21 branch libraries serving the various Smithsonian Institution museums and research centers. The Libraries and Archives serve Smithsonian Institution ...Charles Fuller Baker Field Book, 1923 American entomologists [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylem
Xylem is one of the two types of transport tissue in vascular plants, the other being phloem. The basic function of xylem is to transport water from roots to stems and leaves, but it also transports nutrients. The word ''xylem'' is derived from the Ancient Greek word (''xylon''), meaning "wood"; the best-known xylem tissue is wood, though it is found throughout a plant. The term was introduced by Carl Nägeli in 1858. Structure The most distinctive xylem cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called ''vessels''. Xylem also contains two other type of cells: parenchyma and fibers. Xylem can be found: * in vascular bundles, present in non-woody plants and non-woody parts of woody plants * in secondary xylem, laid down by a meristem called the vascular cambium in woody plants * as part of a stelar arrangement n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Pepper
The bell pepper (also known as paprika, sweet pepper, pepper, or capsicum ) is the fruit of plants in the Grossum Group of the species ''Capsicum annuum''. Cultivars of the plant produce fruits in different colors, including red, yellow, orange, green, white, chocolate, candy cane striped, and purple. Bell peppers are sometimes grouped with less pungent chili varieties as "sweet peppers". While they are fruits—botanically classified as berries—they are commonly used as a vegetable ingredient or side dish. Other varieties of the genus ''Capsicum'' are categorized as ''chili peppers'' when they are cultivated for their pungency, including some varieties of ''Capsicum annuum''. Peppers are native to Mexico, Central America, and northern South America. Pepper seeds were imported to Spain in 1493 and then spread through Europe and Asia. The mild bell pepper cultivar was developed in the 1920s, in Szeged, Hungary. Preferred growing conditions for bell peppers include warm, mois ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucumber
Cucumber (''Cucumis sativus'') is a widely-cultivated Vine#Horticultural climbing plants, creeping vine plant in the Cucurbitaceae family that bears usually cylindrical Fruit, fruits, which are used as culinary vegetables.Cucumber " ''Encyclopædia Britannica''. [1998] 2019. Considered an annual plant, there are three main varieties of cucumber—slicing, Pickled cucumber, pickling, and Seedless fruit, seedless—within which several cultivars have been created. The cucumber originates from South Asia, but now grows on most continents, as many different types of cucumber are traded on the global market. In North America, the term ''wild cucumber'' refers to plants in the Genus, genera ''Echinocystis'' and ''Marah (plant), Marah'', though the two are not closely related. Description The cucumber is a Vine# ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cantaloupe
The cantaloupe, rockmelon (Australia and New Zealand, although cantaloupe is used in some states of Australia), sweet melon, or spanspek (Southern Africa) is a melon that is a variety of the muskmelon species (''Cucumis melo'') from the family Cucurbitaceae. Cantaloupes range in weight from . Originally, ''cantaloupe'' referred only to the non-netted, orange-fleshed melons of Europe, but today may refer to any orange-fleshed melon of the ''C. melo'' species. Etymology and origin The name ''cantaloupe'' was derived in the 18th century via French from The Cantus Region of Italian , which was formerly a papal county seat near Rome, after the fruit was introduced there from Armenia. It was first mentioned in English literature in 1739. The cantaloupe most likely originated in a region from South Asia to Africa. It was later introduced to Europe, and around 1890, became a commercial crop in the United States. ''Melon'' derived from use in Old French as during the 13th century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beans
A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes throughout the world. Terminology The word "bean" and its Germanic cognates (e.g. German '' Bohne'') have existed in common use in West Germanic languages since before the 12th century, referring to broad beans, chickpeas, and other pod-borne seeds. This was long before the New World genus '' Phaseolus'' was known in Europe. After Columbian-era contact between Europe and the Americas, use of the word was extended to pod-borne seeds of ''Phaseolus'', such as the common bean and the runner bean, and the related genus ''Vigna''. The term has long been applied generally to many other seeds of similar form, such as Old World soybeans, peas, other vetches, and lupins, and even to those with slighter resemblances, such as coffee beans, vanilla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beet Curly Top Virus
''Beet curly top virus'' (BCTV) is a pathogenic plant virus of the family ''Geminiviridae'', containing a single-stranded DNA. The family ''Geminiviridae'' consists of nine genera (''Becurtovirus'', ''Begomovirus'', ''Capulavirus'', ''Curtovirus'', ''Eragrovirus'', ''Grablovirus'', ''Mastrevirus'', ''Topocuvirus'', ''Turncurtovirus'') based on their host range, virus genome structure, and type of insect Vector (epidemiology), vector. BCTV is a Curtovirus affecting hundreds of plants. The only known vector is the beet leafhopper, which is native to the Western United States. History ''Beet curly top virus'' was first discovered in 1888 in the Western parts of the United States. The virus wasn't fully recognized until 1907 when people started to realize that the virus was affecting their crops which led to increasing Crop yield, yield loss. As the BCTV began to surface and multiply within the United States, it affected many states (California, Idaho, Utah, and Washington) located in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrus Stubborn Disease
The Citrus stubborn disease is a plant disease affecting species in the genus ''Citrus''. '' Spiroplasma citri'', a Mollicute bacterium species, is the causative agent of the disease. It is present in the phloem of the affected plant. Originally discovered transmitted by several leafhoppers including ''Circulifer tenellus'' (beet leafhopper) and '' Scaphytopius nitridus'' in citrus-growing regions of California, it is now spread by the same hoppers in Arizona and '' Circulifer haematoceps'' in the Mediterranean region. The host most notably affected is sweet orange but the bacterium can also infect weeds such as periwinkle ('' Vinca rosea'') and London rocket (''Sisymbrium irio''). Yellowed plants of Chinese cabbage and pak-choi (''Brassica rapa'') can be infected by ''S. citri''. In the wild, shortpod mustard ('' Hirschfeldia incana'') infested by the beet leafhopper, ''Circulifer tenellus'', can prove to be an important reservoir of infection. ''S. citri'' can also be transmitted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prokaryote
A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connections". Pearson Education. San Francisco: 2003. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: ''Bacteria'' (formerly Eubacteria) and ''Archaea'' (formerly Archaebacteria). Organisms with nuclei are placed in a third domain, Eukaryota. In the study of the origins of life, prokaryotes are thought to have arisen before eukaryotes. Besides the absence of a nucleus, prokaryotes also lack mitochondria, or most of the other membrane-bound organelles that characterize the eukaryotic cell. It was once thought that prokaryotic cellular components within the cytop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiroplasma Citri
''Spiroplasma citri'' is a bacterium species and the causative agent of Citrus stubborn disease. Its genome has been partially sequenced. The restriction enzyme SciNI, with the cutting site 5' GCGC / 3' CGCG, can be found in ''S. citri''. ''Euscelis incisa'' can be used as a vector of the bacterium to experimentally infect white clover (''Trifolium repens ''Trifolium repens'', the white clover, is a herbaceous perennial plant in the bean family Fabaceae (otherwise known as Leguminosae). It is native to Europe, including the British Isles,Clapham, A.R., Tutin, T.G. and Warburg., E.F. 1968. ''Excursio ...'').Spiroplasmas are the causal agents of citrus little-leaf disease. P. G. Markham, R. Townsend, M. Bar-Joseph, M. J. Daniels, A. Plaskitt and B. M. Meddins, Annals of Applied Biology, September 1974, Volume 78, Issue 1, pages 49–57, References External linksType strain of ''Spiroplasma citri'' at Bac''Dive'' - the Bacterial Diversity Metadatabase Mollicutes Bacteri ... [...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 salivary gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmoid Function
A sigmoid function is a mathematical function having a characteristic "S"-shaped curve or sigmoid curve. A common example of a sigmoid function is the logistic function shown in the first figure and defined by the formula: :S(x) = \frac = \frac=1-S(-x). Other standard sigmoid functions are given in the Examples section. In some fields, most notably in the context of artificial neural networks, the term "sigmoid function" is used as an alias for the logistic function. Special cases of the sigmoid function include the Gompertz curve (used in modeling systems that saturate at large values of x) and the ogee curve (used in the spillway of some dams). Sigmoid functions have domain of all real numbers, with return (response) value commonly monotonically increasing but could be decreasing. Sigmoid functions most often show a return value (y axis) in the range 0 to 1. Another commonly used range is from −1 to 1. A wide variety of sigmoid functions including the logistic and hype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
