Agri Books

Disease of Rice/Paddy with their picture, causal organism, symptoms and management is mention below:

1. Blast or rotten neck of Rice/Paddy

Caused by Pyricularia oryzae.

• Most severe Blast or rotten neck disease of rice, known as ‘rich man’s disease’ because high N, high relative humidity and night temperature of 20°C are congenial for fungus.
• The fungus attacks the crop at all stages of crop growth (leaves, seed, panicle, nodes, etc.)
• Affected plant shows diamond shaped lesions, eye-shaped spots with grey or dark brown margin from leaf and leaf sheath.
• Air borne disease:- Conidia spread by wind cause secondary infection.
• Favorable conditions:- Low night temperature (15-20 ℃) & high Relative humidity 93-99%.

Management

• Seed treatment with organomercurials like Agrosan GN @ 2.5 g/kg seed.
• Use of resistance varieties of paddy like Jaya, IR 8, IR 24, IR 64 etc.

2. Brown leaf spot of Rice/Paddy

Caused by: Helminthosporium oryzae or Cochliobolus miyabeanus.

• Responsible for Bengal famine of 1943.
• Symptoms appear as minute spots on the coleoptile, leaf blade, leaf sheath, and glume, being most prominent on the leaf blade and glumes.

Favorable conditions

• Temperature of 25-30with relative humidity above 80 per cent are highly favorable.
• Severe on K deficient soils.

Management

• Treat the seeds with Thiram or Captan at 4 kg/kg.

3. BLB (bacterial leaf blight) of Rice/Paddy

Caused by Xanthomonas oryzae.

• bacterial leaf blight of rice is called Killer disease of rice.
• ‘kresek‘ symptom is seen in seedlings, 1-2 weeks after transplanting.
• Ooze test is used for this disease.

Management

• Balance dose of Nitrogen because high N can make the disease aggressive.
• Use of tolerant varieties like IR 20, Pusa 2-21, TKM-6, Ajay etc.

4. Sheath blight of Rice/Paddy

Due to Rhizoctonia solani.

• Occurs in areas with high temperature (22-32°C) and relative humidity (85-100%)

5. Foot rot or bakanae disease or foolish seedling disease

Caused by Gibberella fujikuroi (prefect stage is Fusarium moniliforme)

• Kurosova; a Japanese scientist isolated GA from Gibberella fujikuroi fungus and found the cause of this disease.
• Due to this stunted growth and infertile seeds

Other Disease of Rice