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Cankers
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 and animals can spread canker, thereby endangering areas that have only slight amount of canker. 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'' * Ash bacterial canker, now understood to be caused by the bacterium '' Pseudomonas savastanoi'', rather than ''Pseudomonas syringae''. After DNA-relatedness studies ''Pseudomonas savastanoi'' has be ... [...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 tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butternut Canker
''Ophiognomonia clavigignenti-juglandacearum'' is a mitosporic fungus that causes the lethal disease of butternut trees (''Juglans cinerea''), butternut canker. 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 ''S. 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 fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sirococcus Clavigignenti-juglandacearum
''Ophiognomonia clavigignenti-juglandacearum'' is a mitosporic fungus that causes the lethal disease of butternut trees (''Juglans cinerea''), butternut canker. 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 ''S. 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 Servic ... [...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. Distribution The distribution range of ''J. cinerea'' extends east to New Brunswick, and from southern Quebec west to Minnesota, south to northern Alabama and southwest to northern Arkansas. It is absent from most of the Southern United States. The species also proliferates at middle elevations (about above sea level) in the Columbia River basin, Pacific Northwest; as an off-site species. Trees with (over mature) class range diameter at breast height were noted in the Imnaha River drainage as late as January 26, 2015. Butternut favors a cooler climate than black walnut and its range does not extend into the Deep South. Its northern range extends into Wisconsin and Minnesota where the growing s ... [...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 s ... [...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 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, 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 arginine dihydrolase and oxidase activity, and forms the polymer le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cypress Canker
Cypress canker is a disease affecting ''Cupressus'' species, caused by one of several species of fungus in the genus ''Seiridium''. Infection causes die-back of twigs and branches in susceptible cypress trees, with rapidly increasing amounts of damage and the death of the tree. History The first epidemic of cypress canker was recorded in California in 1928, with Monterey cypress (''Cupressus macrocarpa'') being affected. Within a few years the local populations of this tree had been killed. The species is widely traded as an ornamental tree and the disease had soon spread worldwide, probably with nursery stock. Within five decades the disease had reached New Zealand, France, Chile, Italy, Argentina, Greece, most of Europe, Canada, North Africa, South Africa and Australia. The causal agent of this pandemic spread was the pathogenic fungus ''Seiridium cardinale'', with '' Seiridium cupressi'' and '' Seiridium unicorne'' sometimes being involved, but being less aggressive; other pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrus Canker
Citrus canker is a disease affecting ''Citrus'' species caused by the bacterium '' Xanthomonas'' (''X.axonopodis; X. campestris''). 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. 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 axonopodis'' is a rod-shaped Gram-negative bacterium with polar flagella. The bacterium has a genome length around 5 megabase pairs. A number of types of citrus canker diseases are caused by different pathovars and varian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honey Locust
The honey locust (''Gleditsia triacanthos''), also known as the thorny locust or thorny honeylocust, is a deciduous tree in the family Fabaceae, native to central North America where it is mostly found in the moist soil of river valleys. Honey locust is highly adaptable to different environments, has been introduced worldwide, and can be an aggressive, invasive species outside of its native range. Description The honey locust, ''Gleditsia triacanthos'', can reach a height of . They exhibit fast growth, but live a medium life span of about 120 years. The leaves are pinnately compound on older trees but bipinnately compound on vigorous young trees. The leaflets are (smaller on bipinnate leaves) and bright green. They turn yellow in the autumn. Honey locusts leaf out relatively late in spring, but generally slightly earlier than the black locust (''Robinia pseudoacacia''). The strongly scented, cream-colored flowers appear in late spring, in clusters emerging from the bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutypa Lata
Phomopsis cane and leaf spot occurs wherever grapes are grown. Phomopsis cane and leaf spot is more severe in grape-growing regions characterized by a humid temperate climate through the growing season. Crop losses up to 30% have been reported to be caused by Phomopsis cane and leaf spot.Úrbez-Torres, J. R., Peduto, F., Smith, R. J., and Gubler, W. D. 2013. Phomopsis dieback: A grapevine trunk disease caused by Phomopsis viticola in California. Plant Dis. 97:1571-1579. Hosts and symptoms Phomopsis cane and leaf spot is a disease that causes symptoms in the common grapevine species, ''vitis vinifera'', in many regions of the world. This disease is mainly caused by the fungal pathogen, ''Phomopsis viticola'', and is known to affect many cultivars of table grapes, such as Thompson Seedless, Red Globe, and Flame Seedless. Also in vines of oenological interest, such as Cabernet Sauvignon, Zinfandel, Syrah, Barbera, Chardonnay and Merlot. Spots or lesions on shoots and leaves are commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dead Arm (grapes)
Phomopsis cane and leaf spot occurs wherever grapes are grown. Phomopsis cane and leaf spot is more severe in grape-growing regions characterized by a humid temperate climate through the growing season. Crop losses up to 30% have been reported to be caused by Phomopsis cane and leaf spot.Úrbez-Torres, J. R., Peduto, F., Smith, R. J., and Gubler, W. D. 2013. Phomopsis dieback: A grapevine trunk disease caused by Phomopsis viticola in California. Plant Dis. 97:1571-1579. Hosts and symptoms Phomopsis cane and leaf spot is a disease that causes symptoms in the common grapevine species, ''vitis vinifera'', in many regions of the world. This disease is mainly caused by the fungal pathogen, ''Phomopsis viticola'', and is known to affect many cultivars of table grapes, such as Thompson Seedless, Red Globe, and Flame Seedless. Also in vines of oenological interest, such as Cabernet Sauvignon, Zinfandel, Syrah, Barbera, Chardonnay and Merlot. Spots or lesions on shoots and leaves are commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
