Brown leaf spot disease of rice is caused by:

Correct option is A

Brown leaf spot of rice is caused by Drechslera oryzae .
Brown Spot Disease:
Causal organism: Bipolaris oryzae, Cochilobolus miyabeans (synonyms Dreschlera oryzae, Helminthosporium oryzae)
· Cause: Fungal disease affecting both seedlings and mature plants.
· Impact on Seedlings: Causes blight; infected seeds lead to 10-58% seedling mortality.
· Historical Significance: Major cause of the Great Bengal Famine (1942), leading to 50-90% yield loss and 2 million deaths.
· Yield Loss:
· Bengal (1942): 50-90% loss due to continuous 20-30°C temperature, cloudy weather, and high rainfall.
· Guyana: Up to 45% loss in severe cases and 12% in moderate cases.
· Favorable Conditions: High temperature, excessive rainfall, and cloudy weather during flowering and grain-filling stages.
Management:
· Soil Nutrition: Maintain well-balanced nutrients to prevent deficiency-related stress.
· Water Management: Avoid drought or water stress.
· Resistant Varieties: Use resistant/tolerant cultivars for cost-effective control.
· Seed Treatment: Treat seeds with captan, thiram, chitosan, carbendazim, or mancozeb (fungus survives up to 4 years in seeds).
· Field Hygiene: Remove rice debris and weeds to reduce infection sources.
· Hot Water Treatment: Soak seeds in 53-54°C water for 10-12 minutes before sowing.
· Chemical Control: Apply Fugi-one @ 500-750 ml/ha.