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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] |
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 centimetres t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impatiens Downy Mildew
''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 J. ... [...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] |
Gavel (fungicide)
A gavel is a small ceremonial mallet commonly made of hardwood, typically fashioned with a handle. It can be used to call for attention or to punctuate rulings and proclamations and is a symbol of the authority and right to act officially in the capacity of a presiding officer. It is often struck against a sound block, a striking surface typically also made of hardwood, to enhance its sounding qualities. According to tradition, Vice President of the United States John Adams used a gavel as a call to order in the first U.S. Senate in New York in 1789. Since then, it has remained customary to tap the gavel against a lectern or desk to indicate the opening and closing of proceedings and, in the United States, to indicate that a judge’s decision is final. It is also used to keep the meeting itself calm and orderly. Etymology In Medieval England, the word ''gavel'' could refer to a tribute or rent payment made with something other than cash.See dictionary definitions of "gavel" aMer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bine (botany)
A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themselves, for instance, when used in wicker work.Jackson; Benjamin; Daydon (1928). ''A Glossary of Botanic Terms with their Derivation and Accent'', 4th ed. London: Gerald Duckworth & Co. In parts of the world, including the British Isles, the term "vine" usually applies exclusively to grapevines (''Vitis''), while the term "climber" is used for all climbing plants. Growth forms Certain plants always grow as vines, while a few grow as vines only part of the time. For instance, poison ivy and bittersweet can grow as low shrubs when support is not available, but will become vines when support is available. A vine displays a growth form based on very long stems. This has two purposes. A vine may use rock exposures, other plants, or other s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 which, in addition to bitterness, they impart floral, fruity, or citrus flavours and aromas. Hops are also used for various purposes in other beverages and herbal medicine. The hops plants have separate female and male plants, and only female plants are used for commercial production. The hop plant is a vigorous, climbing, herbaceous perennial, usually trained to grow up strings in a field called a hopfield, hop garden (in the South of England), or hop yard (in the West Country and United States) when grown commercially. Many different varieties of hops are grown by farmers around the world, with different types used for particular styles of beer. The first documented use of hops in beer is from the 9th century, though Hildegard of Bingen, 30 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmopara Viticola
''Plasmopara viticola'', the causal agent of grapevine downy mildew, is a heterothallic oomycete that overwinters as oospores in leaf litter and soil. In the spring, oospores germinate to produce macrosporangia, which under wet condition release zoospores. Zoospores are splashed by rain into the canopy, where they swim to and infect through stomata. After 7–10 days, yellow lesions appear on foliage. During favorable weather, the lesions sporulate and new secondary infections occur. Description ''Plasmopara viticola'', also known as grape downy mildew, is considered to be the most devastating disease of grapevines in climates with relatively warm and humid summers. It was first observed in 1834 by Schweinitz on ''Vitis aestivalis'' in the southeastern United States. Shortly after this first observation, the pathogen was introduced to European countries where it played a devastating role in the yield and production of their grapes, and consequently their wine. France was among th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrullus Lanatus
Watermelon (''Citrullus lanatus'') is a flowering plant species of the Cucurbitaceae family and the name of its edible fruit. A scrambling and trailing vine-like plant, it is a highly cultivated fruit worldwide, with more than 1,000 varieties. Watermelon is grown in favorable climates from tropical to temperate regions worldwide for its large edible fruit, which is a berry with a hard rind and no internal divisions, and is botanically called a ''pepo''. The sweet, juicy flesh is usually deep red to pink, with many black seeds, although seedless varieties exist. The fruit can be eaten raw or pickled, and the rind is edible after cooking. It may also be consumed as a juice or an ingredient in mixed beverages. Kordofan melons from Sudan are the closest relatives and may be progenitors of modern, cultivated watermelons. Wild watermelon seeds were found in Uan Muhuggiag, a prehistoric site in Libya that dates to approximately 3500. Watermelons were domesticated in north-east ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squash (plant)
''Cucurbita'' (Latin for gourd) is a genus of herbaceous fruits in the gourd family, Cucurbitaceae (also known as ''cucurbits'' or ''cucurbi''), native to the Andes and Mesoamerica. Five edible species are grown and consumed for their flesh and seeds. They are variously known as squash, pumpkin, or gourd, depending on species, variety, and local parlance. Other kinds of gourd, also called bottle-gourds, are native to Africa and belong to the genus ''Lagenaria'', which is in the same family and subfamily as ''Cucurbita'', but in a different tribe. These other gourds are used as utensils or vessels, and their young fruits are eaten much like those of the ''Cucurbita'' species. Most ''Cucurbita'' species are herbaceous vines that grow several meters in length and have tendrils, but non-vining "bush" cultivars of ''C. pepo'' and ''C. maxima'' have also been developed. The yellow or orange flowers on a ''Cucurbita'' plant are of two types: female and male. The female flowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumpkin
A pumpkin is a vernacular term for mature winter squash of species and varieties in the genus ''Cucurbita'' that has culinary and cultural significance but no agreed upon botanical or scientific meaning. The term ''pumpkin'' is sometimes used interchangeably with "squash" or "winter squash", and is commonly used for cultivars of ''Cucurbita argyrosperma'', ''Cucurbita ficifolia'', ''Cucurbita maxima'', ''Cucurbita moschata'', and ''Cucurbita pepo''. Native to North America (northeastern Mexico and the southern United States), ''C. pepo'' pumpkins are one of the oldest domesticated plants, having been used as early as 7,000 to 5,500 BC. Today, pumpkins of varied species are widely grown for food, as well as for aesthetic and recreational purposes. The pumpkin's thick shell contains edible seeds and pulp. Pumpkin pie, for instance, is a traditional part of Thanksgiving meals in Canada and the United States, and pumpkins are frequently carved as jack-o'-lanterns for decoration a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucumis Sativus
Cucumber (''Cucumis sativus'') is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as culinary vegetables.Cucumber " ''''. 2019. Considered an annual plant, there are three main varieties of cucumber—slicing, , and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucumis Melo
''Cucumis melo'', also known as melon, is a species of ''Cucumis'' that has been developed into many cultivated varieties. The fruit is a pepo. The flesh is either sweet or bland, with or without a musky aroma, and the rind can be smooth (such as honeydew), ribbed (such as European cantaloupe), wrinkled (such as casaba melon), or netted (such as muskmelon). In North America, the sweet-flesh varieties are often collectively called muskmelon, including the musky netted-rind varieties and the inodorous smooth-rind varieties, and cantaloupe usually means the former type. However, muskmelon in a narrow sense only refers to the musky netted-rind type, while the true cantaloupe is the European type with ribbed and often warty rind that is seldom grown in North America. The origin of melons is not known. Research has revealed that seeds and rootstocks were among the goods traded along the caravan routes of the Ancient World. Some botanists consider melons native to the Levant and Egypt, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
