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Pythium In Turfgrass
''Pythium'' disease, also known as "''Pythium'' blight," "cottony blight," or "grease spot," is a highly destructive turfgrass disease caused by several different ''Pythium'' species. All naturally cultivated cool-season turfgrasses are susceptible to ''Pythium'' and if conditions are favorable to ''Pythium'' it can destroy a whole turfgrass stand in a few days or less. ''Pythium'' favors hot and very humid weather and will usually develop in low areas or swales in the turfgrass. Symptoms ''Pythium'' symptoms will first appear as small, irregularly shaped spots that are 1/2" to 4" inches in diameter and will join together to form large patches that will often be long streaks. ''Pythium'' often develops into these streaks because it is the direction of water movement (drainage) most often ruts from golf carts and mowing equipment. The turfgrass leaves will at first look and feel water-soaked, greasy, or slimy. Once dew or moisture dries up the blade will shrivel up and collapse, ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turfgrass
A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. Lawns are usually composed only of grass species, subject to weed and pest control, maintained in a green color (e.g., by watering), and are regularly mowed to ensure an acceptable length. Lawns are used around houses, apartments, commercial buildings and offices. Many city parks also have large lawn areas. In recreational contexts, the specialised names turf, pitch, field or green may be used, depending on the sport and the continent. The term "lawn", referring to a managed grass space, dates to at least than the 16th century. With suburban expansion, the lawn has become culturally ingrained in some areas of the world as part of the desired household aesthetic.Robbins, PaulLawn People: How Grasses, Weeds, and Chemicals Make Us Who We Are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythium
''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but '' Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequently a vector for their transmission. Morphology ;Hyphae: ''Pythium'' species, like others in the family Pythiaceae, are usually characterized by their production of coenocytic hyphae without septations. ;Oogonia: Generally contain a single oospore. ;Antheridia: Contain an elongated and club-shaped antheridium. Ecological importance ''Pythium''-induced root rot is a common crop disease. When the organism kills newly emerged or emerging seedlings, it is known as damping off, and is a very common problem in fields and greenhouses. Thus there is tremendous interest in genetic host resistance, but no crop has ever developed adequate resistance to ''Pythium''. This disease complex usually involves other pathogens such as '' Phytophthor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycelium
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. 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 active transport. Mycelia are vital in terrestrial and aquatic ecosystems for their role ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaline
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases. Etymology The word "alkali" is derived from Arabic ''al qalīy'' (or ''alkali''), meaning ''the calcined ashes'' (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide (''slaked lim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oospore
An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. They are believed to have evolved either through the Somatic fusion, fusion of two species or the chemically-induced stimulation of mycelia, leading to oospore formation. In Oomycetes, oospores can also result from asexual reproduction, by apomixis. These are found in fungi as sexual spores which help the sexual reproduction of fungi. These haploid, non-motile spores are the site of meiosis and karyogamy in oomycetes. A dormant oospore, when observed under an electron microscope, has led researchers to draw conclusion that there is only a single central globule with other storage bodies surrounding it. References Reproduction {{biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perennial Ryegrass
''Lolium perenne'', common name perennial ryegrass, English ryegrass, winter ryegrass, or ray grass, is a grass from the family Poaceae. It is native to Europe, Asia and northern Africa, but is widely cultivated and naturalised around the world. Description The plant is a low-growing, tufted, hairless grass, with a bunching (or tillering) growth habit. The leaves are dark green, smooth and glossy on the lower surface, with untoothed parallel sides and prominent parallel veins on the upper surface. The leaves are folded lengthwise in bud (unlike the rolled leaves of Italian ryegrass, '' Lolium multiflorum'') with a strong central keel, giving a flattened appearance. The ligule is very short and truncated and often difficult to see. The small white auricles grip the stem at the base of the leaf blade. Leaf sheaths at the base are usually tinged pink and hairless. Stems grow up to 90 cm. The inflorescence is unbranched, with spikelets on alternating sides edgeways-on to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kentucky Bluegrass
''Poa pratensis'', commonly known as Kentucky bluegrass (or blue grass), smooth meadow-grass, or common meadow-grass, is a perennial species of grass native to practically all of Europe, North Asia and the mountains of Algeria and Morocco. Although the species is spread over all of the cool, humid parts of the United States, it is not native to North America. The Spanish Empire brought the seeds of Kentucky bluegrass to the New World in mixtures with other grasses. In its native range, ''Poa pratensis'' forms a valuable pasture plant, characteristic of well-drained, fertile soil. It is also used for making lawns in parks and gardens and has established itself as a common invasive weed across cool moist climates like the Pacific Northwest and the Northeastern United States. When found on native grasslands in Canada, for example, it is considered an unwelcome exotic plant, and is indicative of a disturbed and degraded landscape. Taxonomy ''Poa pratensis'' was one of the many spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fescue
''Festuca'' (fescue) is a genus of flowering plants belonging to the grass family Poaceae (subfamily Pooideae). They are evergreen or herbaceous perennial tufted grasses with a height range of and a cosmopolitan distribution, occurring on every continent except Antarctica. The genus is closely related to ryegrass (''Lolium''), and recent evidence from phylogenetic studies using DNA sequencing of plant mitochondrial DNA shows that the genus lacks monophyly. As a result, plant taxonomists have moved several species, including the forage grasses tall fescue and meadow fescue, from the genus ''Festuca'' into the genus ''Lolium'', or alternatively into the segregate genus '' Schedonorus''. Because the taxonomy is complex, scientists have not determined how many true species belong to the genus, but estimates range from more than 400 to over 640.Darbyshire, S. J. and L. E. Pavlick''Festuca''. Grass Manual. Flora of North America. Fescue pollen is a significant contributor t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bentgrass
''Agrostis'' (bent or bentgrass) is a large and very nearly cosmopolitan genus of plants in the grass family, found in nearly all the countries in the world. It has been bred as a GMO creeping bent grass. Species * ''Agrostis aequivalvi'' (Arctic bent) * ''Agrostis agrostiflora'' * ''Agrostis alpina'' * ''Agrostis ambatoensis'' * '' Agrostis × amurensis'' * '' Agrostis anadyrensis'' * '' Agrostis angrenica'' * '' Agrostis arvensis'' * ''Agrostis atlantica'' * ''Agrostis australiensis'' * ''Agrostis bacillata'' * ''Agrostis balansae'' * ''Agrostis barceloi'' * ''Agrostis basalis'' * ''Agrostis bergiana'' * ''Agrostis bettyae'' * ''Agrostis × bjoerkmannii'' * ''Agrostis blasdalei'' * ''Agrostis boliviana'' * ''Agrostis boormanii'' * ''Agrostis bourgaei'' * ''Agrostis boyacensis'' * ''Agrostis brachiata'' * ''Agrostis brachyathera'' * ''Agrostis breviculmis'' * ''Agrostis burmanica'' * '' Agrostis calderoniae'' * ''Agrostis canina'' (velvet bent) * ''Agro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeration
Aeration (also called aerification or aeriation) is the process by which air is circulated through, mixed with or dissolved in a liquid or other substances that act as a fluid (such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions. Aeration of liquids Methods Aeration of liquids (usually water) is achieved by: * passing air through the liquid by means of the Venturi tube, aeration turbines or compressed air which can be combined with diffuser(s) air stone(s), as well as fine bubble diffusers, coarse bubble diffusers or linear aeration tubing. Ceramics are suitable for this purpose, often involving dispersion of fine air or gas bubbles through the porous ceramic into a liquid. The smaller the bubbles, the more gas is exposed to the liquid increasing the gas transfer efficiency. Diffusers or spargers can also be designed into the system to cause turbulence or mixing if desired. Porous ceramic diffu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Sulfate
Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen and 24% sulfur. Uses The primary use of ammonium sulfate is as a fertilizer for alkaline soils. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth. The main disadvantage to the use of ammonium sulfate is its low nitrogen content relative to ammonium nitrate, which elevates transportation costs.Karl-Heinz Zapp "Ammonium Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2012, Wiley-VCH, Weinheim. It is also used as an agricultural spray adjuvant for water-soluble insecticides, herbicides, and fungicides. There, it functions to bind iron and calcium cations that are present in both well water and pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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