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Spot-causing fungal disease. At first, the lesions are net blotch of 1-2cm in length and 1-5mm in width. Later they become brown to black stripe of 1-3cm in length and 5-8mm in width. The lesions are often not so characteristic, but they are more distinct in the backside of the leaf. The disease often causes leaf blight when the lesions enlarge. The species of the causal organism is same with that of ryegrass net blotch, but the pathogenicity is differentiated. |
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Fungal disease which causes plant withering under snowfall and distributes in north of Kanto. Stem and leaf under snow soften, wither, and look pink. The sclerotia are not formed. As for the turf in non-snowfall region, the occurrence is reported. The causal organism is known to produce nivalenol and deoxynivalenol as mycotoxins, but the Japanese isolates were elucidated not to produce them by recent researches. |
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The fungal disease occurring mainly in meadow fescue. The symptom begins to appear at the early spring before the occurrence of crown rust with swelling lesions which are peculiar to the rust disease. The lesions are reddish brown to iron rust color, oval to sripe, 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 can infect fescue and the alternate host is not found. |
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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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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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