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Spot-causing fungal disease which causes summer depression of grasslands in the warm regions. The lesions are at first water-soaked small spots and then expands to faint reddish brown to orange, oval to spindle shaped ones of 5-10mm in length and 2-4mm in width. The fungal tissues, setae, are produced in the center of the old lesion and looks black moldy. Orange masses of spores are formed on the lesion under wet conditions and they disperse by wind and rain. The disease often occurs from the end of the rainy season to summer. The species of the pathogen is same with those of sorghum, ryegrass and bahiagrass, but the pathogenicity is considered to be differentiated. |
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Important rust disease with large damage. The disease occurs comparatively a lot in the warm regions south of Kanto. The lesions are at first yellow swelling and then become oval ones of 1-2 mm in length and 0.5 mm in width. The epidermis tears and yellow to orange urediniospores appears from the inside. When occurring severely, the entire leaf looks yellow powdery and then withers. Blackish brown telia are produced later, but the pathogen is considered to overwinter and oversummer by urediniospores. The species of the causal organism is same with that of crown rust of fescue and ryegrass. |
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The disease was observed in Tochigi prefecture, the central part of Japan in 1970's. Lesions are mainly produced in the edge and center of the leaves along the veins. They are first grayish brown, later reddish brown, then stretch long to spindle-shaped or streak ones. At last they become 1-3mm wide and the base of the lesions reached to the sheaths causing leaf death. The causal organism is often obtained from the killed leaves of bentgrass abroad. |
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Fungal disease which causes leaf blight. The lesions are at first brown small spots, and later turn to ones of olive color and yellow to yellowish brown halos are formed in the surroundings. In the latter stage, the lesions turn to ash white and collapse from the center part, fuse mutually, and cause leaf blight. |
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Fungal disease occurring in Hokkaido. The lesions are at first reddish brown in the leaf and then become ash white, rectangular ones delimited by the leaf vein. It produces red purple halo in the surroundings of the lesions. The lesions fuse mutually and cause leaf blight. |
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Fungal disease which causes leaf spot. The lesion is dark brown to black, oval to spindle shape. Later the center part of lesions fade to ash white, so they look circular. The surface of the old lesions becomes white because slimy mass of conidia is formed. The disease occurs a lot in cool high lands such as Hokkaido and Nagano. |
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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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