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Thousand Cankers Disease
Thousand cankers disease (TCD) is a recently recognized disease of certain walnuts (''Juglans'' spp.). The disease results from the combined activity of the walnut twig beetle (''Pityophthorus juglandis'') and a canker producing fungus, '' Geosmithia morbida''. Until July 2010 the disease was only known to the western United States where over the past decade it has been involved in several large scale die-offs of walnut, particularly black walnut, '' Juglans nigra''. However, in late July 2010 a well-established outbreak of the disease was found in the Knoxville, Tennessee, area. This new finding is the first locating it within the native range of its susceptible host, black walnut. In 2013, an outbreak was found in the Veneto region of Italy, where the disease has been found on both black walnut and English walnut. Description Adult walnut twig beetles carry spores of the ''Geosmithia morbida'' fungus, which grows profusely around the pupal chamber of the beetles. Following ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosmithia Morbida
Geosmithia morbida is a mitosporic ascomycete fungus belonging to the order Hypocreales and the family Bionectriaceae. This fungus is recognized as the causal agent of Thousand Cankers Disease (TCD), a significant threat to walnut trees. The disease derives its name from the multitude of coalescing cortical cankers that develop around the entrance holes created by its insect vector, the walnut twig beetle (''Pityophthorus juglandis''). The relationship between ''Geosmithia morbida'' and ''Pityophthorus juglandis'' is symbiotic, with the beetle carrying the fungal conidia on its body and introducing them to healthy walnut trees as it bores through the bark. While the greatest damage is observed on black walnuts (''Juglans nigra''). Invasiveness TCD was first seen in the western United States. In 2010 it was found in Tennessee, which was the first time it appeared in the eastern part of the country. This raised worries because the eastern US has many native black walnut trees, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloem
Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Ancient Greek word (''phloiós''), meaning "bark". The term was introduced by Carl Nägeli in 1858. Different types of phloem can be distinguished. The early phloem formed in the growth apices is called protophloem. Protophloem eventually becomes obliterated once it connects to the durable phloem in mature organs, the metaphloem. Further, secondary phloem is formed during the thickening of stem structures. Structure Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juglans Microcarpa
''Juglans microcarpa'', known also as the little walnut, Texas walnut, Texas black walnut or little black walnut (as it belongs to the "black walnuts" section ''Juglans'' sect. ''Rhysocaryon''), is a large shrub or small tree (10–30 ft tall) which grows wild along streams and ravines in Texas, New Mexico, Oklahoma, and Kansas, and the northernmost states of Mexico. It produces nuts with a width of 1/2—3/4 in. The pinnately compound leaves bear 7—25 untoothed to finely-toothed leaflets, each 1/4—1/2 in wide. It is found at elevations ranging from 700 ft to 6700 ft. Two varieties are recognized: ''J. microcarpa'' var. ''microcarpa'' and ''J. microcarpa'' var. ''stewartii''. Where the range of ''J. microcarpa'' overlaps with '' J. major'', the two species interbreed, producing populations with intermediate characteristics. This phenomenon has also been found where ''J. microcarpa'' trees grows near '' J. nigra'' tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juglans Californica
''Juglans californica'', the California black walnut, also called the California walnut, or the Southern California black walnut, is a large shrub or small tree (about ) of the walnut family, Juglandaceae, endemic to the Central Valley and the Coast Range valleys from Northern to Southern California. Distribution ''Juglans californica'' is generally found in the valleys and adjacent slopes of the California Coast Ranges, Transverse Ranges, and Peninsular Ranges. It grows as part of mixed woodlands, and also on slopes and in valleys wherever conditions are favorable. It is threatened by development and overgrazing. Some native stands remain in urban Los Angeles in the Santa Monica Mountains, Hollywood Hills, and Repetto Hills. ''J. californica'' grows in riparian woodlands, either in single species stands or mixed with California's oaks (''Quercus'' spp.) and cottonwoods ('' Populus fremontii''). Climate model predictions indicate that *Juglans californica* may expand its range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juglans Major
''Juglans major'' (literally, the larger walnut), also known as Arizona walnut, is a Juglans, walnut tree which grows to with a Diameter at breast height, DBH of up to at elevations of in Texas, Oklahoma, New Mexico, Arizona, and Utah. It also occurs in Mexico as far south as Guerrero. Common names include Arizona black walnut (as it belongs to the "black walnuts" Section (botany), section ''Juglans'' sect. ''Rhysocaryon''), and the Spanish (language), Spanish name ''nogal cimarrón'' (cimarron walnut). Description In moister areas, the tree features a single, stout trunk; there are usually several slender trunks in drier situations. The 8–14 in long pinnately compound leaves bear 9–15 lanceolate leaflets, wide by long. The small nut has a thick shell with deep grooves enclosing an oily, edible seed. ''J. major'' grows primarily in canyons or riparian areas, near springs, and other areas with shallow groundwater. Where the range of ''J. major'' overla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Susceptibility (botany)
Susceptibility may refer to: Physics and engineering In physics the susceptibility is a quantification for the change of an extensive property under variation of an intensive property. The word may refer to: * In physics, the susceptibility of a material or substance describes its response to an applied field. For example: ** Magnetic susceptibility ** Electric susceptibility * The two types of susceptibility above are examples of a linear response function; sometimes the terms ''susceptibility'' and ''linear response function'' are used interchangeably. *In electromagnetic compatibility (EMC), susceptibility is the sensitivity of a device's function to incoming electromagnetic interference Health and medicine * In epidemiology, a susceptible individual is a member of a population who is at risk of becoming infected by a disease * In microbiology, pharmacology, and medicine drug susceptibility is the ability of a microorganism to be inhibited or killed by the drug, as in antibio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host (biology)
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasite, parasitic, a mutualism (biology), mutualistic, or a commensalism, commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include animals playing host to parasitic worms (e.g. nematodes), cell (biology), cells harbouring pathogenic (disease-causing) viruses, or a Fabaceae, bean plant hosting mutualistic (helpful) Rhizobia, nitrogen-fixing bacteria. More specifically in botany, a host plant supplies nutrient, food resources to micropredators, which have an evolutionarily stable strategy, evolutionarily stable relationship with their hosts similar to ectoparasitism. The host range is the collection of hosts that an organism can use as a partner. Symbiosis Symbiosis spans a wide variety of possible relationships between organisms, differing in their permanence and their effects on the two parties. If one of the partners in an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilting
Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non- lignified plant cells falls towards zero, as a result of diminished water in the cells. Wilting also serves to reduce water loss, as it makes the leaves expose less surface area. The rate of loss of water from the plant is greater than the absorption of water in the plant. The process of wilting modifies the leaf angle distribution of the plant (or canopy) towards more erectophile conditions. Lower water availability may result from: * drought conditions, where the soil moisture drops below conditions most favorable for plant functioning; * the temperature falls to the point where the plant's vascular system cannot function; * high salinity, which causes water to diffuse from the plant cells and induce shrinkage; * saturated soil conditions, where roots are unable to obtain sufficient oxygen for cellular respiration, and so are unable to transport water into the plant; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symptom
Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showing on a medical scan. A symptom is something out of the ordinary that is experienced by an individual such as feeling feverish, a headache or other pains in the body, which occur as the body's immune system fights off an infection. Signs and symptoms Signs A medical sign is an objective observable indication of a disease, injury, or medical condition that may be detected during a physical examination. These signs may be visible, such as a rash or bruise, or otherwise detectable such as by using a stethoscope or taking blood pressure. Medical signs, along with symptoms, help in forming a diagnosis. Some examples of signs are nail clubbing of either the fingernail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bark Beetle
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus '' Scolytus'', namely the European elm bark beetle ''S. multistriatus'' and the large elm bark beetle ''S. scolytus'', which like the American elm bark beetle '' Hylurgopinus rufipes'', transmit Dutch elm disease fungi (''Ophiostoma''). The mountain pine beetle ''Dendroctonus ponderosae'', southern pine beetle '' Dendroctonus frontalis'', and their near relatives are major pests of conifer forests in North America. A similarly aggres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nutrient
A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted into smaller molecules in the process of releasing energy such as for carbohydrates, lipids, proteins and fermentation products ( ethanol or vinegar) leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bark (botany)
Bark is the outermost layer of Plant stem, stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the Tissue (biology), tissues outside the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner bark, which in older Plant stem, stems is living tissue, includes the innermost layer of the periderm. The outer bark on older stems includes the dead tissue on the surface of the stems, along with parts of the outermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the living periderm is also called the Glossary of botanical terms#rhytidome, rhytidome. Products derived from bark include bark shingle siding and wall coverings, spices, and other flavorings, tanbark for tannin, resin, latex, medicines, poisons, various hallucinogenic chemicals, and Cork (material), cork. Bark has been used to make clot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
