PGRFA

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The Disease:  SHEATH ROT
Pathogen:
Sarocladium oryzae (Sawada) (Gams and Hawksworth 1975)

Etymology: from Greek saron, broom; klados, branch.
Disease:
Sheath rot occurs in all rice-growing countries. It causes significant yield loss during rainy season in both rainfed and upland ecosystems. Chen (1957) reported losses up to 85% in Taiwan. In India, Chakravorty and Biswas (1978) noted that sheath rot reduced yields of some varieties by 9.6 - 26.0%. Kang and Rattan (1983) reported losses up to 50% in Punjab.
Symptoms:
Sheath rot appears on the uppermost leaf sheath which encloses the emerging panicle. Sheath rot lesions are irregular, 0.5 - 1.5 cm long, and have grayish centers and brownish margins. Sometimes the whole lesion appears gray-brown. In infected tillers, panicles emerge partially or not at all. Inside the sheath, a whitish powdery mass of fungus can be seen. Grains discolor brown. In the tropics, it is easily confused with sheath discoloration (caused by many Pseudomonas pathogens).
Appearance:
sarocladium oryzae habit sheath rot
Last Updated on Wednesday, 15 April 2009 07:26