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Canker
A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticulture. Their causes include a wide range of organisms as fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are bound to a unique host species or genus, but a few will attack other plants. Weather (via frost or windstorm damage) and animal damage can also cause stress to the plant resulting in cankers. Other causes of cankers is pruning when the bark is wet or using un-sterilized tools. Although fungicides or bactericides can treat some cankers, often the only available treatment is to destroy the infected plant to contain the disease. Examples * Apple canker, caused by the fungus '' Neonectria galligena'' formerly Nectria galligena. * Ash bacterial canker, now understood to be caused by the bacterium '' Pseu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrus Canker
Citrus canker is a disease affecting ''Citrus'' species caused by the bacterium '' Xanthomonas citri''. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. While not harmful to humans, canker significantly affects the vitality of citrus trees, causing leaves and fruit to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. Citrus canker is mainly a leaf-spotting and rind-blemishing disease, but when conditions are highly favorable, it can cause defoliation, shoot dieback, and fruit drop. The disease, which is believed to have originated in Southeast Asia, is extremely persistent when it becomes established in an area. Citrus groves have been destroyed in attempts to eradicate the disease. Countries like Brazil and the United States also suffer from canker outbreaks. Biology ''Xanthomonas citri'' is a rod-shaped Gram-negative bacterium with polar flagella. The bacterium ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butternut Canker
''Ophiognomonia clavigignenti-juglandacearum'' is a mitosporic fungus that causes the butternut canker, a lethal disease of butternut (tree), butternut trees (''Juglans cinerea''). It is also known to parasitize other members of the genus ''Walnut, Juglans'' on occasion, and very rarely other related trees including Hickory, hickories. The fungus is found throughout North America, occurring on up to 91% of butternut trees, and may be threatening the viability of butternut as a species. Distribution Butternut, the primary host of ''O. clavigignenti-juglandacearum'', is found in mixed hardwood forests throughout central North America, from New Brunswick to North Carolina. The pathogen was identified as an invasive species in 1967. It was first discovered in Wisconsin, but has since spread to other states and into Canada, making the butternut an endangered species in Ontario. Its native origin is unknown, but possibly in Asia given the resistance of Asian walnuts to the disease. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neonectria Galligena
''Neonectria ditissima'' (syn. ''Neonectria galligena'') is a fungal plant pathogen. It causes cankers that can kill branches of trees by choking them off. Apple and beech trees are two susceptible species. Host range ''Neonectria ditissima'' host range encompass a variety of hardwood tree species such as, ''Fagus'', ''Populus'', ''Salix'', ''Betula'' and ''Acer'' species. These tree species population are present in both America and Europe. Phylogenetic studies have revealed genetic divergence among both populations, at specific loci (ß-tubulin, RPB2). However, due to high levels of within-population diversity of the American populations, it has been hypothesized that America is ''N. ditissima'' place of origin. Disease management ''Neonectria ditissima'' is a difficult pathogen to eradicate—but there are many ways to limit its spread and infection rate. Effective control requires a combination of cultural and chemical treatments. Cultural control Multiple cultural techniq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sirococcus Clavigignenti-juglandacearum
''Ophiognomonia clavigignenti-juglandacearum'' is a mitosporic fungus that causes the butternut canker, a lethal disease of butternut trees (''Juglans cinerea''). It is also known to parasitize other members of the genus ''Juglans'' on occasion, and very rarely other related trees including hickories. The fungus is found throughout North America, occurring on up to 91% of butternut trees, and may be threatening the viability of butternut as a species. Distribution Butternut, the primary host of ''O. clavigignenti-juglandacearum'', is found in mixed hardwood forests throughout central North America, from New Brunswick to North Carolina. The pathogen was identified as an invasive species in 1967. It was first discovered in Wisconsin, but has since spread to other states and into Canada, making the butternut an endangered species in Ontario. Its native origin is unknown, but possibly in Asia given the resistance of Asian walnuts to the disease. The United States Forest Service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleeding Canker Of Horse Chestnut
Bleeding canker of horse chestnut is a common canker of horse chestnut trees (''Aesculus hippocastanum'', also known as conker trees) that is known to be caused by infection with several different pathogens. Infections by the gram-negative fluorescent bacterium ''Pseudomonas syringae'' pathovar ''aesculi'' are a new phenomenon, and have caused most of the bleeding cankers on horse chestnut that are now frequently seen in Britain. Disease cycle ''Pseudomonas syringae pv. Aesculi'' is a bacterium that causes bleeding canker of horse chestnut. The pathogen overwinters in the soil and can survive in the soil for about a year. It is spread by water, rain, and tools that were used on the infected tree. It causes lesions on the bark of the tree that can be near the base of the trunk or higher. The bleeding from the cankers mostly occurs in the spring and fall. Infection of the tree through lenticels and leaf scars when inoculated in a study occurred most readily in the spring and sum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosmithia Putterillii
The foamy bark canker is a disease affecting oak trees in California caused by the fungus ''Geosmithia sp. #41'' and spread by the Western oak bark beetle ('' Pseudopityophthorus pubipennis''). This disease is only seen through the symbiosis of the bark beetles and the fungal pathogen. The bark beetles target oak trees and bore holes through the peridermal tissues, making tunnels within the phloem. The fungal spores are brought into these tunnels by the beetles and begin to colonize the damaged cells inside the tunnels. Symptoms of the developing fungus include wet discoloration seeping from the beetle entry holes as the fungus begins to consume phloem and likely other tissues. If bark is removed, necrosis of the phloem can be observed surrounding the entry hole(s). As the disease progresses, a reddish sap and foamy liquid oozes from entry holes, thus giving the disease the name foamy bark canker. Eventually, after the disease has progressed, the tree dies. This disease is impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seiridium
''Seiridium'' is a genus of plant pathogens in the family Sporocadaceae. The genus '' Lepteutypa'' is teleomorphic (reproducing sexually) and the corresponding anamorphic name, used to describe the asexual form, is ''Seiridium'' (formerly ''Coryneum''). For instance, the name ''Seiridium cupressi'' is still be used for the anamorphic form of that species, but now that it is known that a sexual stage exists, the name ''Lepteutypa cupressi''. On the other hand, no sexual stage of species '' Seiridium cardinale'' is known, so that is its only name. '' Seiridium cardinale'' is important to gardeners and foresters as they cause the devastating Cypress canker disease on ''Cupressus'', ''Thuja'', and related conifers in Northern Europe, America, Australia, and New Zealand. ''Seiridium cardinale'' is from California and was introduced to Europe around the 1930s, probably from infected nursery stock. A separate introduction affected the southern hemisphere. Species As accepted by Spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ash Tree
''Fraxinus'' (), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae, and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some subtropical species are evergreen trees. The genus is widespread throughout much of Europe, Asia, and North America. The leaves are opposite (rarely in whorls of three), and mostly pinnately compound, though simple in a few species. The seeds, popularly known as "keys" or "helicopter seeds", are a type of fruit known as a samara. Some ''Fraxinus'' species are dioecious, having male and female flowers on separate plants but sex in ash is expressed as a continuum between male and female individuals, dominated by unisexual trees. With age, ash may change their sexual function from predominantly male and hermaphrodite towards femaleness; if grown as an ornamental and both sexes are present, ashes can cause a considerable litter problem with their seeds. Rowans, or mounta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomonas Syringae
''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathology, plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from international culture collections such as the NCPPB, International Collection of Microorganisms from Plants, ICMP, and others. ''Pseudomonas syringae'' is a member of the genus ''Pseudomonas'', and based on 16S rRNA analysis, it has been placed in the ''P. syringae'' group. It is named after the lilac tree (''Syringa vulgaris''), from which it was first isolated. A phylogenomic analysis of 494 complete genomes from the entire ''Pseudomonas'' genus showed that ''P. syringae'' does not form a monophyletic species in the strict sense, but a wider evolutionary group that also included other species as well, such as ''P. avellanae'', ''P. savastanoi'', ''P. amygdali'', and ''P. cerasi''. ''Pseudomonas syringae'' tests negative for Ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butternut (tree)
''Juglans cinerea'', commonly known as butternut or white walnut,Snow, Charles Henry ''The Principal Species of Wood: Their Characteristic Properties'' 2nd ed. New York: John Wiley & Sons, 1908. p. 56. is a species of walnut native to the eastern United States and southeast Canada. Description ''J. cinerea'' is a deciduous tree growing to tall, rarely more. Butternut is a slow-growing species, and rarely lives longer than 75 years. It has a stem diameter, with light gray Bark (botany), bark. The leaves are alternate (botany), alternate and pinnate, long, with 11–17 leaflets, each leaflet long and broad. Leaves have a terminal leaflet at the end of the leafstalk and have an odd number of leaflets. The whole leaf is downy-pubescent, and a somewhat brighter, yellower green than many other tree leaves. Flowering and fruiting Like other members of the family Juglandaceae, butternut's leafout in spring is tied to photoperiod rather than air temperature and occurs whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bactericide
A bactericide or bacteriocide, sometimes abbreviated Bcidal, is a substance which kills bacteria. Bactericides are disinfectants, antiseptics, or antibiotics. However, material surfaces can also have bactericidal properties based solely on their physical surface structure, as for example biomaterials like insect wings. Disinfectants The most used disinfectants are those applying *active chlorine (i.e., hypochlorites, chloramines, dichloroisocyanurate and trichloroisocyanurate, wet chlorine, chlorine dioxide, etc.), *active oxygen (peroxides, such as peracetic acid, potassium persulfate, sodium perborate, sodium percarbonate, and urea perhydrate), *iodine (povidone-iodine, Lugol's solution, iodine tincture, iodinated nonionic surfactants), *concentrated alcohols (mainly ethanol, 1-propanol, called also n-propanol and 2-propanol, called isopropanol and mixtures thereof; further, 2-phenoxyethanol and 1- and 2-phenoxypropanols are used), *phenols, phenolic substances (such as ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
