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Pseudoperonospora
''Pseudoperonospora'' is a genus of water moulds which includes several species known for causing downy mildew infections on plants. Species include: * '' Pseudoperonospora cannabina'' - causes downy mildew on hemp * ''Pseudoperonospora cubensis'' - causes downy mildew on cucurbits * ''Pseudoperonospora humuli'' - causes downy mildew on hops Hops are the flowers (also called seed cones or strobiles) of the hop plant ''Humulus lupulus'', a member of the Cannabaceae family of flowering plants. They are used primarily as a bittering, flavouring, and stability agent in beer, to whi ... References Water mould genera Water mould plant pathogens and diseases Peronosporales {{watermould-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoperonospora Cubensis
''Pseudoperonospora cubensis'' is a species of water mould known for causing downy mildew on cucurbits such as cantaloupe, cucumber, pumpkin, squash and watermelon. This water mould is an important pathogen of all these crops, especially in areas with high humidity and rainfall, such as the eastern United States. In most years the disease is an annual, late-season problem on squash and pumpkin in the eastern and central United States, however, since 2004 it has become one of the most important diseases in cucumber production. Considered a highly destructive foliar disease of cucurbits, successful breeding in the mid-twentieth century provided adequate control of downy mildew in cucumber without the use of fungicides. The resurgence in virulence has caused growers great concern and substantial economic losses, while downy mildew in other cucurbit crops continues to be a yearly hindrance. Symptoms and signs The pathogen causes angular chlorotic lesions on the foliage. These lesio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoperonospora Humuli
''Pseudoperonospora humuli'' is a plant pathogen that causes downy mildew on hops. Hosts and symptoms Downy mildew on hops is caused by the pathogen ''Pseudoperonospora humuli'', an oomycete protist. ''P. humuli'' is an obligate biotrophic pathogen, meaning that it can only live and grow in living host tissue. ''P. humuli,'' like most downy mildews, is highly host-specific and thus will only infect hop (''Humulus lupulus'') and also Japanese hop (''Humulus japonicas''). The most characteristic symptom of hop downy mildew are the “basal spikes” that form on the plant. These structures result from systemically infected shoots and are “stunted and have brittle, downward-curled leaves from which masses of purple to black sporangiophores and sporangia are produced.” These spikes can exist as three distinct types: 1) “Primary spikes”, which arise from infected hop crowns 2) “Secondary spikes”, which arise from infected apical meristems 3) “Aerial sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoperonospora Cannabina
''Pseudoperonospora cannabina'' is a plant pathogen that causes downy mildew, which is a fungal-like disease caused by an oomycete. Host and symptoms The host of this disease is hemp ('' Cannabis sativa''). The disease has been observed in Europe and parts of Asia, and on wild hemp in Illinois, suggesting that it has spread to the Western hemisphere. The symptoms that correspond with this disease include discoloration of the leaves, irregular leaf shape and death of the leaves. The leaves will begin to turn yellow, and eventually the entire plant can die. A way to diagnose this disease is to look at the underside of the leaves. The fungus grows through the top side of the leaf and makes its fruiting body on the underside. The fruiting body is where sporangia are produced, and from the sporangia, zoospores are released, which are the infectious stage of this disease cycle. Environment Downy mildew of hemp requires cool, moist weather in order to produce spores. Usually these are ... [...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 infected ... [...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] |
Cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively, ''C. ruderalis'' may be included within ''C. sativa'', all three may be treated as subspecies of ''C. sativa'', or ''C. sativa'' may be accepted as a single undivided species. The genus is widely accepted as being indigenous to and originating from Asia. The plant is also known as hemp, although this term is often used to refer only to varieties of ''Cannabis'' cultivated for non-drug use. Cannabis has long been used for hemp fibre, hemp seeds and their oils, hemp leaves for use as vegetables and as juice, medicinal purposes, and as a recreational drug. Industrial hemp products are made from cannabis plants selected to produce an abundance of fibre. Various cannabis strains have been bred, often selectively to pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucurbitaceae
The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family consisting of about 965 species in around 95 genera, of which the most important to humans are: *''Cucurbita'' – squash, pumpkin, zucchini, some gourds *''Lagenaria'' – calabash, and others that are inedible *''Citrullus'' – watermelon (''C. lanatus'', ''C. colocynthis'') and others *''Cucumis'' – cucumber (''C. sativus''), various melons and vines *''Momordica'' – bitter melon *''Luffa'' – the common name is also luffa, sometimes spelled loofah (when fully ripened, two species of this fibrous fruit are the source of the loofah scrubbing sponge) *''Cyclanthera'' – Caigua The plants in this family are grown around the tropics and in temperate areas, where those with edible fruits were among the earliest cultivated plants in both the Old and New Worlds. The family Cucurbitaceae ranks among the highest of plant families for number and percentage of species used as human food. The name ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humulus
''Humulus'', hop, is a small genus of flowering plants in the family Cannabaceae. The hop is native to temperate regions of the Northern Hemisphere. Hops are the female flowers (seed cones, strobiles) of the hop species '' H. lupulus''; as a main flavor and aroma ingredient in many beer styles, ''H. lupulus'' is widely cultivated for use by the brewing industry. Description Although frequently referred to in American literature as the hops "vine", it is technically a bine; unlike vines, which use tendrils, suckers, and other appendages for attaching themselves, bines have stout stems with stiff hairs to aid in climbing. In British literature the term “vine” is generally reserved for the grape genus ''Vitis''. ''Humulus'' is described as a twining perennial herbaceous plant which sends up new shoots in early spring and dies back to the cold-hardy rhizome in autumn. Hop shoots grow very rapidly, and at the peak of growth can grow per week. Hop bines climb by wrapping clockwise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Mould Genera
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 ab ... [...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 co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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