|
Plasmopara Obducens
''Plasmopara obducens'' is a species of oomycete that causes Impatiens downy mildew. It was first described on ''Impatiens noli-tangere'' in Germany in 1877. ''Plasmopara obducens'' is known from native species of ''Impatiens'' since the 1800s, but outbreaks on cultivated varieties of ''Impatiens walleriana'' started in 2003 in the United Kingdom and in 2004 in the United States. The outbreak spread worldwide by 2016. Morphology Sporangiophores are an average of 373 (260-484) micrometers with the first branch appearing at 197 (120-271) micrometers. Sporangia are 16 (13-18) micrometers by 13 (11-16) micrometers. Resting spores are globose with a diameter of 28 micrometers Disease symptoms Initially, leaves are stippled or yellowed. Infected leaves curl downward. A white down is often present on the underside of the leaves; buds and stems may also develop a down. Eventually, the leaves fall off the plant leaving just stems. In about a week, the plants are dead. Taxonomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oomycete
Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of male antheridia and female oogonia; these spores can overwinter and are known as resting spores. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite '' Pythium oligandrum'', is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds (or water moulds), although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impatiens
''Impatiens'' is a genus of more than 1,000 species of flowering plants, widely distributed throughout the Northern Hemisphere and the tropics. Together with the genus '' Hydrocera'' (one species), ''Impatiens'' make up the family Balsaminaceae. Common names in North America include impatiens, jewelweed, touch-me-not, snapweed and patience. As a rule-of-thumb, "jewelweed" is used exclusively for Nearctic species, and balsam is usually applied to tropical species. In the British Isles by far the most common names are impatiens and busy lizzie, especially for the many varieties, hybrids and cultivars involving ''Impatiens walleriana''. "Busy lizzie" is also found in the American literature. The invasive alien ''Impatiens glandulifera'' is commonly called policeman's helmet in the UK. Description Most ''Impatiens'' species are herbaceous annuals or perennials with succulent stems. Only a few woody species exist. Plant size varies depending on the species, from five centime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downy Mildew
Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of crucifers, grapes and vegetables that grow on vines. The prime example is '' Peronospora farinosa'' featured in NCBI-Taxonomy and HYP3. This pathogen does not produce survival structures in the northern states of the United States, and overwinters as live mildew colonies in Gulf Coast states. It progresses northward with cucurbit production each spring. Yield loss associated with downy mildew is most likely related to soft rots that occur after plant canopies collapse and sunburn occurs on fruit. Cucurbit downy mildew only affects leaves of cucurbit plants. Symptoms Initial symptoms include large, angular or blocky, yellow areas visible on the upper surface. As lesions mature, they expand rapidly and turn brown. The under surface of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impatiens Noli-tangere
''Impatiens noli-tangere'' (touch-me-not balsam; Latin ''impatiēns'' "impatient" or "not allowing", and ''nōlī tangere'' "do not touch": literally "be unwilling to touch") is an annual herbaceous plant in the family Balsaminaceae found in damp places in Europe, Asia and North America. The yellow flowers are followed by pods which forcefully explode when ripe, ejecting the seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ... for some distance. It is also called touch-me-not, yellow balsam, jewelweed, western touch-me-not or wild balsam. File:Illustration Impatiens noli-tangere0.jpg, Botanical illustration by Otto Wilhelm Thomé, 1885 File:Große Springkraut (Impatiens noli-tangere).jpg, Flower closeup References External links Jepson Manual Treatment [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impatiens Walleriana
''Impatiens walleriana'' (syn. ''Impatiens sultanii''), also known as busy Lizzie (British Isles), balsam, sultana, or simply impatiens, is a species of the genus ''Impatiens'', native to eastern Africa from Kenya to Mozambique. The Latin specific epithet ''walleriana'' honours a British missionary, Horace Waller (1833–1896). Description It is a flowering herbaceous perennial plant growing to tall, with broad lanceolate leaves 3–12 cm long and 2–5 cm broad. Leaves are mostly alternate, although they may be opposite near the top of the plant. The changeable, simple leaves are stalked 1.5 to 6 cm long. The leaf blade is ovate to broadly elliptic, sometimes obovate, 2.5 to 13 inches long and 2 to 5.5 inches wide, green and sometimes spotted or pink or reddish on the underside. Leaflets are missing. The hermaphroditic, zygomorphic flowers are profusely borne, 2–5 cm diameter, with five petals and a 1 cm spur. The seedpod explodes when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many List of islands of the United Kingdom, smaller islands within the British Isles. Northern Ireland shares Republic of Ireland–United Kingdom border, a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five major unincorporated territories, nine United States Minor Outlying Islands, Minor Outlying Islands, and 326 Indian reservations. The United States is also in Compact of Free Association, free association with three Oceania, Pacific Island Sovereign state, sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Palau, Republic of Palau. It is the world's List of countries and dependencies by area, third-largest country by both land and total area. It shares land borders Canada–United States border, with Canada to its north and Mexico–United States border, with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peronospora
''Peronospora'' is a genus of oomycetes that are obligate plant pathogens of many eudicots. Most species in this group produce a downy mildew disease, which can cause severe damage to many different cultivated crops, as well as wild and ornamental plants. There are 19 genera that produce downy mildew, and ''Peronospora'' has been placed alongside ''Pseudoperonospora'' in the group of downy mildews with coloured conidia. ''Peronospora'' has far more species than any other genus of the downy mildews. However, many species have been moved from this genus to be reclassified to other or new genera. Among these was the most famous ''Peronospora'' species, formerly known as ''Peronospora parasitica'', and now known as '' Hyaloperonospora parasitica''. Now, the ''Peronospora'' species of most importance is likely the ''Peronospora tabacina''. ''Peronospora tabacina'' causes blue mold on tobacco plants and can severely reduce yields of this economically important crop to the point where it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmopara
''Plasmopara'' is a genus of Oomycota. ''Plasmopara'' species are plant pathogens, causing downy mildew on carrot, parsley, parsnip, chervil, and impatiens ''Impatiens'' is a genus of more than 1,000 species of flowering plants, widely distributed throughout the Northern Hemisphere and the tropics. Together with the genus '' Hydrocera'' (one species), ''Impatiens'' make up the family Balsaminace .... References Further reading * * * External links * Water mould plant pathogens and diseases Peronosporales Water mould genera {{plant-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science News
''Science News (SN)'' is an American bi-weekly magazine devoted to articles about new scientific and technical developments, typically gleaned from recent scientific and technical journals. History ''Science News'' has been published since 1922 by Society for Science & the Public, a non-profit organization founded by E. W. Scripps in 1920. American chemist Edwin Slosson served as the publication's first editor. From 1922 to 1966, it was called ''Science News Letter''. The title was changed to ''Science News'' with the March 12, 1966 issue (vol. 89, no. 11). Tom Siegfried was the editor from 2007 to 2012. In 2012, Siegfried stepped down, and Eva Emerson became the Editor in Chief of the magazine. In 2017, Eva Emerson stepped down to become the editor of a new digital magazine, Annual Reviews. On February 1, 2018 Nancy Shute became the Editor in Chief of the magazine. In April 2008, the magazine changed from a weekly format to the current biweekly format, and the website ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Mould Plant Pathogens And Diseases
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food, energy or organic micronutrients. Its chemical formula, H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. "Water" is also the name of the liquid state of H2O at standard temperature and pressure. A number of natural states of water exist. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water covers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.png "Click for more on -> Oomycete")
.svg "Click for more on -> United Kingdom")
.svg "Click for more on -> Water Mould Plant Pathogens And Diseases")