Important fungal disease which causes plant death occurring in cool and wet regions. The small spots appears at first and then the leaf and stalk turn to yellow and wither. The disease progresses gradually under the snowfall. The stem, leaf and root rot to ash white according to increase of the temperature after snow-melting in the spring of next year. White and fluffy hyphae are produced on the surface of the withering plant and large black sclerotia of irregular types and about 8-10mm in size are produced before long. They germinate in autumn and produce light brown stroma of 3-8 mm in diameter. The ascospores spread from the stroma and the infection happens again. The host range of the causal organism is wide including alfalfa and vetches. DNA markers for the QTL controlling resistance to the disease have been developed.
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Fungal disease which produces spots in the leaf. It occurs mainly in the rainy season and autumn. The lesions are at first small and drab to brown ones. Then they expand gradually and become brown to dark brown lesions of about 5-10mm in diameter with characteristic zonations. The lesions are often darker and with clearer zonation in red clover than in white clover. The species of the causal organisms of Stemphylium leaf spot are different in red clover and white clover. The white clover fungi does not invade red clover.
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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 5 mm 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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