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Powdery Mildew Of Barley
Powdery mildew is a fungal disease of barley caused by ''Blumeria graminis'' f. sp. ''hordei''. The disease has a worldwide distribution and is most damaging in cool, wet climates. The host range of the form species ''hordei'' is restricted to barley and other ''Hordeum species''. Symptoms At first, powdery mildew can be observed as small greyish patches of fluffy fungal growth (mycelium) on the upper surface of the lower leaves. These spots resemble small cushions of white powder. Leaf tissue on the opposite side of an infected leaf turns pale green to yellow. The fungus only infects the epidermal layer and can be easily scraped off with a fingernail. Infections can also occur on the leaf sheaths and ears. Leaves remain green and active for some time following infection, then gradually become chlorotic and die off. As the disease progresses, the mycelium often becomes dotted with minute black points (cleistothecia), which are the sexual fruiting bodies of the fungus. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blumeria Graminis
''Blumeria graminis'' (commonly called barley powdery mildew or corn mildew) is a fungus that causes powdery mildew on grasses, including cereals. It is the only species in the genus ''Blumeria''. It has also been called ''Erysiphe graminis'' and (by its anamorph) ''Oidium monilioides'' or ''Oidium tritici''. Systematics Previously ''B. graminis'' was included within the genus '' Erysiphe'', but molecular studies have placed it into a clade of its own. Thus since 1975, the species ''graminis'' was moved into the new taxa ''Blumeria'' of which it is the only species. ''Blumeria'' differs from ''Erysiphe'' in its digitate haustoria and in details of the conidial wall. As well ''Blumeria'' is considered to be phylogenetically distinct from ''Erisiphe'' as it is a plant pathogen that hosts solely on the true grasses of ''Poaceae. '' Eight special forms or '' formae speciales'' (ff.spp.) of ''B. graminis'' have been distinguished, each of which is parasitic on a particular genus of g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |