|
''Phytophthora'' (from Greek φυτόν (''phytón''), “plant” and φθορά (''phthorá''), “destruction”; “the plant-destroyer”) is a genus of plant-damaging Oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The cell wall of'' Phytophthora'' is made up of cellulose. The genus was first described by Heinrich Anton de Bary in 1875. Approximately 100 species have been described, although 100–500 undiscovered ''Phytophthora'' species are estimated to exist.〔Brasier CM, 2009. (Phytophthora biodiversity: how many Phytophthora species are there? ) In: Goheen EM, Frankel SJ, eds. Phytophthoras in Forests and Natural Ecosystems. Albany, CA, USA: USDA Forest Service: General Technical Report PSW-GTR-221, 101–15.〕 ==Pathogenicity== ''Phytophthora'' spp. are mostly pathogens of dicotyledons, and are relatively host-specific parasites. Many species of ''Phytophthora'' are plant pathogens of considerable economic importance. ''Phytophthora infestans'' was the infective agent of the potato blight that caused the Great Irish Famine (1845–1849), and still remains the most destructive pathogen of solanaceous crops, including tomato and potato. The soya bean root and stem rot agent, ''Phytophthora sojae'', has also caused longstanding problems for the agricultural industry. In general, plant diseases caused by this genus are difficult to control chemically, thus the growth of resistant cultivars is the main management strategy. Other important ''Phytophthora'' diseases are: * ''Phytophthora'' taxon Agathis—causes collar-rot on New Zealand kauri (''Agathis australis''), New Zealand's most voluminous tree, an otherwise successful survivor of the Jurassic * ''Phytophthora cactorum''—causes rhododendron root rot affecting rhododendrons, azaleas and causes bleeding canker in hardwood trees * ''Phytophthora capsici''—infects Cucurbitaceae fruits, such as cucumbers and squash * ''Phytophthora cinnamomi''—causes cinnamon root rot affecting woody ornamentals including arborvitae, azalea, Chamaecyparis, dogwood, forsythia, Fraser fir, hemlock, Japanese holly, juniper, Pieris, rhododendron, Taxus, white pine, American chestnut and Australian Jarrah. * ''Phytophthora fragariae''—causes red root rot affecting strawberries * ''Phytophthora kernoviae''—pathogen of beech and rhododendron, also occurring on other trees and shrubs including oak, and holm oak. First seen in Cornwall, UK, in 2003. * ''Phytophthora megakarya''—one of the cocoa black pod disease species, is invasive and probably responsible for the greatest cocoa crop loss in Africa * ''Phytophthora nicotianae''—infects onions * ''Phytophthora palmivora''—causes fruit rot in coconuts and betel nuts * ''Phytophthora ramorum''—infects over 60 plant genera and over 100 host species; causes sudden oak death〔("APHIS List of Regulated Hosts and Plants Associated with ''Phytophthora ramorum''" U.S. Animal and Plant Health Inspection Services );〕 * ''Phytophthora quercina''—causes oak death * ''Phytophthora sojae''—causes soybean root rot Research beginning in the 1990s has placed some of the responsibility for European forest die-back on the activity of imported Asian ''Phytophthoras''.〔("''Phytophthora'': Asiatischer Pilz lässt die Bäume sterben" ''Süddeutschen Zeitung'' 11 May 2005 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Phytophthora」の詳細全文を読む スポンサード リンク
|