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Important, spot-causing fungal disease occurring all over the country. The disease is occurring in Hokkaido, the northern part, through year, although occurring in Kanto area, the central part, in spring and autumn. The lesions are at first water-soaked small spot, and then become faint orange to ash white with brown border, long spindle to lens shape, 1-3cm in length and 2-5mm in width, characteristic lesions. The lesions fuse gradually and becomes cloud-shaped ones. The infected leaf often tears from the lesion part. The infected plants withers producing a patch and the grassland looks white when occurring severely. The disease occurs severely under the cool and wet condition. Moreover, the seed transmission might happen and the young plant is diseased in results. |
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Important fungal disease which causes plant death in Hokkaido and Tohoku Dist. The disease distributes in the region where the frozen period of soil is long. The entire plant becomes water-soaked and discolors to deep green and softened immediately after snow-melting like boiled. It becomes ash brown when drying and black, large sclerotia of 5-10mm in size like the excrement of rat are formed on the surface. Stroma come out from the sclerotia at late autumn and ascospores disperse as inoculum sources. The causal organism is polyxeny and barley, wheat, fescue, ryegrass, timothy, redtop, and etc. are reported to be infected. Orchardgrass and ryegrass are the weakest grasses to the disease. |
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The important disease with large damage in the rust disease of orchardgrass. The symptom begins to appear at the early spring in the warm region with swelling lesions which are peculiar to the rust disease. The lesions are reddish brown to iron rust color, oval to stripe, 1-2mm in length and 0.5-0.6mm in width. They fuse mutually and becomes irregular shape. The epidermis tears when maturing and it disperses reddish brown urediniospores and spreads. The lesion becomes brown to black, from summer to autumn, forming teleutospore, and overwinters. The causal organism is classified into five races based on the reaction of the orchardgrass ecotype. It invades only orchardgrass in nature and the alternate host is not found. |
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Fungal disease which becomes problem with seed production and occurs in the cool region. The disease occurs in the leaf, sheath, culm, and head spike. The lesions are rectangular shape, ash white, 1-2 mm long with brown thin border. The lesion is delimited by leaf veins and becomes distinct with a clear boundary. The pycnidiospores in the pycnidia formed on the lesion disperse by wind and rain and the disease spreads. |
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Fungal disease occurring in Hokkaido, the northern part of Japan. The damage is not so severe. The black powdery stripes are formed on the leaf, sheath and culm. The surface of the lesion tears and exposes black powder, the smut spores, and they disperse by wind and rain. The lesion part often splits later. |
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An Important fungal disease which occurs all over the country and becomes a cause of summer depression of grassland. Ash green and water-soaked lesions appears at first and the whole infected plant soften like being boiled before long. Then, the infected stalks and leaves fall one upon another and rot when the disease progresses and hyphae like spider' web appear covering all the infected part. Later light brown to brown sclerotia of about 5mm in diameter are produced on the infected part. At this point, the infected grass withers forming patches and the grassland gradually becomes bare land. The causal organism is polyxeny and can infect most grasses and legumes of herbage. AG-1 IA and IB of R.solani cause the disease.
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Fungal disease occurring in the northern region. It often occurs just after the rainy season. The lesions appear irregularly and become spindle shaped, faint brick color to gray with yellow surroundings, 1.5x0.5cm or more in size. They fuse mutually and cause leaf blight. |
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Fungal disease occurring on escaped orchardgrass in Hokkaido, the most northern region of Japan. It is a new disease found in summer, 2003. The lesions are light brown to brown, oval to spindle shaped, 2-10 x 1-3 mm in size. They fuse mutually and cause leaf blight. The pathogen is same with that causes summer leaf spot in ryegrass and fescue. |
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Fungal disease occurring mainly in Hokkaido, the northern part. In the beginning, the leaf is partially covered with black molds and small black grains (pycnidia) appear in this part. Then the black molds extend and causes twisting and malformation in the infected leaf. When occurring severely, it progresses to the culm and the entire plant becomes black with severe twists. |
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Important fungal disease which causes plant death and occurs mainly in Hokkaido, the most northern part of Japan. The symptom is similar that of T.ishikariensis, but the sclerotia formed on the surface of withering part is reddish brown and millet grain size. The sclerotia is formed on the stalks, leaves, and roots, etc. of the withering plant. The pathogen is more saprophytic than T.ishikariensis and is considered to invade after invasion of T.ishikariensis and occur mixingly with it. |
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Important fungal disease which causes plant death and occurs mainly in Hokkaido Dist. The symptom appears just after snow-melting. Stems and leaves become water-soaked and softened like boiled. When they are dry, they discolor to ash brown. Dark brown to black, globular to irregular sclerotia of 0.5-1mm in diameter are produced on them. The pathogen is classified to three different biotypes. Biotype A and B distributes in the much and little snowing regions, respectively. Biotype C distributes in both regions. These groups are different not only in their distribution but also their pathogenicity and fertility, etc. |
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A new disease occurring in Hokkaido, Iwate and etc., the northern part of Japan in 2004 to 2005. The lesions are yellow to yellowish orange, long stripe along the leaf vein. It invades only orchardgrass in nature and the alternate host is not found. |
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Fungal disease that produces large lesions on leaves and occurs mainly in the warm region. The disease at first produces small spindle-shape spots of copper color in the leaf, but the lesion soon becomes a large one with irregular zonation crossing the leaf. The lesions fuses later and this causes leaf blight. The pathogen is a same species with that of sorghum, etc. But some differentiation of pathogenicity are considered to be occurring. |
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