PGRFA

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The Disease:  LEAF SCALD
Pathogen:
Anamorph:  Microdochium oryzae (Hashioka and Yokogi) Samuels and Hallett

Teleomorph: Monographella albescens (Thumen), (Parkinson et al 1981)

Other acceptable names: Gerlachia oryzae (Hashioka and Yokogi), W. Gams;
Rhynchosporium oryzae (Hashioka and Yokogi)

Etymology: from Latin micro, small; Greek docheion, container - referring to the spore-bearing region
Disease:
Leaf scald is common in rice-growing countries. It has been reported to cause considerable damage in Latin America and West Africa.
Symptoms:
Symptoms appear on mature leaves as zonate lesions starting on leaf tips or edges. Lesions are parallel to oblong, with light brown halos. On mature leaves, lesions vary from 1 to 5 cm in length and from 0.5 to 1 cm in breadth. Coalescing lesions may blight the greater part of the leaf blade and extend to 25 cm long. Zonations become indistinct with age.

Kwon et al (1973) in Korea observed typical leaf symptoms, and reddish-brown, small spots on the leaves and long elliptical or rectangular, purplish-black necrotic spots on the leaf sheaths and panicle necks. Spots enlarged and became bright purplish-brown or light gray.

Microdochium oryzae cal also cause coleoptile decay and root rot (De Gutierrez 1960).

Symptom of Leaf scald Seed infected with Microdochium oryzae
Last Updated on Monday, 13 July 2009 03:44