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Specific Replant Disease
Specific replant disease (also known as ‘Sick Soil Syndrome’) is a malady that manifests itself when susceptible plants such as apples, pears, plums, cherries and roses are placed into soil previously occupied by a related species. The exact causes are not known, but in the first year the new plants will grow poorly. Root systems are weak and may become blackened, and plants may fail to establish properly. One theory is that replant disease is due to a whole menagerie of tree pathogens - fungi, bacteria, nematodes, viruses and other organisms. These parasitise target the living tissues of the mature tree, hastening senility and death, and survive in the soil and decaying roots after the tree has died. Putting a young traumatised tree with an immature root system into this 'broth' of pathogens can be too much for an infant tree to cope with. Any new root growth is rapidly and heavily colonised, so that shoot growth is virtually zero. This is especially true if it is on a dwar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple (fruit)
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ''Malus sieversii'', is still found today. Apples have been grown for thousands of years in Asia and Europe and were brought to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, and European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. Generally, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the size of the resulting tree, allowing for easier harvesting. There are more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crop Rotation
Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant pests and weeds. Growing the same crop in the same place for many years in a row, known as monocropping, gradually depletes the soil of certain nutrients and selects for a highly competitive pest and weed community. Without balancing nutrient use and diversifying pest and weed communities, the productivity of monocultures is highly dependent on external inputs. Conversely, a well-designed crop rotation can reduce the need for synthetic fertilizers and herbicides by better using ecosystem services from a diverse set of crops. Additionally, crop rotations can improve soil structure and organic matter, which reduces erosion and increases farm system resilience. History Agriculturalists have long recognized that suitable rotations — such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pear Tree Diseases
Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the pomaceous fruit of the same name. Several species of pears are valued for their edible fruit and juices, while others are cultivated as trees. The tree is medium-sized and native to coastal and mildly temperate regions of Europe, North Africa, and Asia. Pear wood is one of the preferred materials in the manufacture of high-quality woodwind instruments and furniture. About 3,000 known varieties of pears are grown worldwide, which vary in both shape and taste. The fruit is consumed fresh, canned, as juice, or dried. Etymology The word ''pear'' is probably from Germanic ''pera'' as a loanword of Vulgar Latin ''pira'', the plural of ''pirum'', akin to Greek ''apios'' (from Mycenaean ''ápisos''), of Semitic origin (''pirâ''), meaning "fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Tree Diseases
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ''Malus sieversii'', is still found today. Apples have been grown for thousands of years in Asia and Europe and were brought to North America by European colonization of the Americas, European colonists. Apples have Religion, religious and mythology, mythological significance in many cultures, including Norse mythology, Norse, Greek mythology, Greek, and Christianity in Europe, European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. Generally, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after plantin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Pathogens And Diseases
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria). By one definition, plants form the clade Viridiplantae (Latin name for "green plants") which is sister of the Glaucophyta, and consists of the green algae and Embryophyta (land plants). The latter includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, and mosses. Most plants are multicellular organisms. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloropicrin
Chloropicrin, also known as PS and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I. Its chemical structural formula is Cl3CNO2. Synthesis Chloropicrin was discovered in 1848 by Scottish chemist John Stenhouse. He prepared it by the reaction of sodium hypochlorite with picric acid: : HOC6H2(NO2)3 + 11 NaOCl → 3 Cl3CNO2 + 3 Na2CO3 + 3 NaOH + 2 NaCl Because of the precursor used, Stenhouse named the compound chloropicrin, although the two compounds are structurally dissimilar. Today, chloropicrin is manufactured by the reaction of nitromethane with sodium hypochlorite: : H3CNO2 + 3 NaOCl → Cl3CNO2 + 3 NaOH or by the reaction of chloroform with nitric acid: : CHCl3 + HNO3 → CCl3NO2 + H2O Properties Chloropicrin's chemical formula is CCl3NO2 and its molecular weight is 164.38 grams/mole. Pure chloropicrin is a colorless liquid, with a boiling po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromomethane
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula C H3 Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It has a tetrahedral shape and it is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s. Occurrence and manufacture Bromomethane originates from both natural and human sources. In the ocean, marine organisms are estimated to produce 56,000 tonnes annually. It is also produced in small quantities by certain terrestrial plants, such as members of the family Brassicaceae. It is manufactured for agricultural and industrial use by treating methanol with bromine in the presence of sulfur or hydrogen sulfide: :6 CH3OH + 3 Br2 + S → 6 CH3Br + 2 H2O + H2SO4 Uses In 1999, an estimated 71,500 tonnes of synthetic methyl bromide were used annually worldwide. 97% of this estimate was used for fumigation purposes, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Almond
The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genus ''Prunus'', it is classified with the peach in the subgenus ''Amygdalus'', distinguished from the other subgenera by corrugations on the shell (endocarp) surrounding the seed. The fruit of the almond is a drupe, consisting of an outer hull and a hard shell with the seed, which is not a true nut. ''Shelling'' almonds refers to removing the shell to reveal the seed. Almonds are sold shelled or unshelled. Blanched almonds are shelled almonds that have been treated with hot water to soften the seedcoat, which is then removed to reveal the white embryo. Once almonds are cleaned and processed, they can be stored over time. Almonds are used in many food cuisines, often featuring prominently in desserts, such as marzipan. The almond tree p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apricot
An apricot (, ) is a fruit, or the tree that bears the fruit, of several species in the genus ''Prunus''. Usually, an apricot is from the species '' P. armeniaca'', but the fruits of the other species in ''Prunus'' sect. ''Armeniaca'' are also called apricots. Etymology ''Apricot'' first appeared in English in the 16th century as ''abrecock'' from the Middle French ''aubercot'' or later ''abricot'', from Spanish '' albaricoque'' and Catalan ''a(l)bercoc'', in turn from Arabic الْبَرْقُوق (al-barqūq, "the plums"), from Byzantine Greek βερικοκκίᾱ (berikokkíā, "apricot tree"), derived from late Greek ''πραικόκιον'' (''praikókion'', "apricot") from Latin '' ersica ("peach")praecocia'' (''praecoquus'', "early ripening"). Species Apricots are species belonging to ''Prunus'' sect. ''Armeniaca''. The taxonomic position of '' P. brigantina'' is disputed. It is grouped with plum species according to chloroplast DNA sequences, but more closely r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peach
The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-fuzzy varieties), nectarines. The specific name ''persica'' refers to its widespread cultivation in Persia (modern-day Iran), from where it was transplanted to Europe. It belongs to the genus ''Prunus'', which includes the cherry, apricot, almond, and plum, in the rose family. The peach is classified with the almond in the subgenus '' Amygdalus'', distinguished from the other subgenera by the corrugated seed shell (endocarp). Due to their close relatedness, the kernel of a peach stone tastes remarkably similar to almond, and peach stones are often used to make a cheap version of marzipan, known as persipan. Peaches and nectarines are the same species, though they are regarded commercially as different fruits. The skin of nectarines lac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quince
The quince (; ''Cydonia oblonga'') is the sole member of the genus ''Cydonia'' in the Malinae subtribe (which also contains apples and pears, among other fruits) of the Rosaceae family (biology), family. It is a deciduous tree that bears hard, aromatic bright golden-yellow pome fruit, similar in appearance to a pear. Ripe quince fruits are hard, tart, and astringent. They are seldom eaten raw, but are processed into marmalade, jam, paste (known as quince cheese) or alcoholic beverages. The quince tree is also grown as an ornamental plant for its attractive pale pink blossoms and other ornamental qualities. Description The tree grows high and wide. The fruit is long and across. The immature fruit is green with dense grey-white fine hair, most of which rubs off before maturity in late autumn when the fruit changes colour to yellow with hard, strongly perfumed flesh. The leaf, leaves are alternately arranged, simple, long, with an entire margin and densely pubescent with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medlar
''Mespilus germanica'', known as the medlar or common medlar, is a large shrub or small tree in the rose family Rosaceae. The fruit of this tree, also called medlar, has been cultivated since Roman times, is usually available in winter and eaten when bletted. It may be eaten raw and in a range of cooked dishes. When the genus ''Mespilus'' is included in the genus '' Crataegus'', the correct name for this species is ''Crataegus germanica'' (Kuntze). In the southwest of England it historically had a number of vulgar nicknames, such as open-arse and monkey's bottom, due to the appearance of its large calyx. Description Under ideal circumstances, the deciduous plant grows up to tall. Generally, it is shorter and more shrub-like than tree-like. With a lifespan of 30–60 years, the tree is rather short-lived. Its bark is grayish brown with deep vertical cracks forming rectangular plates that tend to lift off. The wild form of ''M. germanica'' is mostly a thorny, more shrub-like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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