Leaf Scald:Microdochium oryzae

Symptoms:

• Zonate lesions of alternating light tan and dark brown starting from leaf tips or edges
• Lesions oblong with light brown halos in mature leaves
• Coalescing of lesions result in blighting of a large part of the leaf blade
• The affected areas dry out giving the leaf a scalded appearance
• Translucent leaf tips and margins
• Infected leaf tips also split near the midrib especially when there are strong wind.

• The conidia are borne on superficial stromata (compact masses of specialized vegetative hyphae) arising from lesions.
• They are bow to new-moon shaped, single-celled when young and 2-celled when mature, occasionally 2-3 septate.
• Asci are cylindrical to club-shaped and unitunicate (an ascus wherein both the inner and outer walls are more or less rigid and do not separate during spore ejection).
• The ascospores are fusoid (tapering towards each end) straight or somewhat curved, 3-5 septate. 
  

Management:

• Avoid high use of fertilizer.
• Chemicals such as benomyl, carbendazim, quitozene and thiophanate-methyl can be used to treat the seeds to eliminate the disease.
• In the field, spraying of benomyl or fentin acetate or validamycin significantly reduce the incidence of leaf scald.
• Foliar application of captafol or mancozeb or copper oxychloride also reduces the incidence and severity of the fungal disease.