PATH354 |Symptoms Etiology Disease Cycle Management of Diseases of Field Crops Rice | Part 1

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Here's a comprehensive overview of diseases of rice, including symptoms, etiology, disease cycle, and management:

Common Diseases of Rice:

1. Blast
2. Leaf Spot
3. Sheath Blight
4. Panicle Blight
5. Root Rot
6. Stem Rot
7. Tungro
8. Bacterial Blight

Symptoms:

1. Blast:
Lesions on leaves, nodes, and panicles
Grayish-white centers with dark margins
Defoliation and reduced yield
2. Leaf Spot:
Small, circular lesions on leaves
Yellowing or necrosis of infected areas
Premature defoliation
3. Sheath Blight:
Elliptical lesions on sheaths and culms
Grayish-white centers with dark margins
Reduced yield and lodging
4. Panicle Blight:
Discoloration and drying of panicles
Reduced grain filling and yield
5. Root Rot:
Soft, rotting roots
Stunted growth and yellowing leaves
Reduced yield
6. Stem Rot:
Soft, rotting stems
Lodging and reduced yield
7. Tungro:
Yellowing or orange discoloration of leaves
Stunted growth and reduced yield
8. Bacterial Blight:
Linear lesions on leaves and stems
Yellowing or necrosis of infected areas
Reduced yield

Etiology:

1. Blast: Magnaporthe oryzae (fungus)
2. Leaf Spot: Cercospora oryzae (fungus)
3. Sheath Blight: Rhizoctonia solani (fungus)
4. Panicle Blight: Fusarium moniliforme (fungus)
5. Root Rot: Various fungi (e.g., Pythium, Phytophthora)
6. Stem Rot: Various fungi (e.g., Sclerotium, Fusarium)
7. Tungro: Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV)
8. Bacterial Blight: Xanthomonas oryzae pv. oryzae (bacterium)

Disease Cycle:

1. Blast:
Spores infect leaves and nodes
Fungus colonizes and produces spores
Spores dispersed by wind and water
2. Leaf Spot:
Spores infect leaves
Fungus colonizes and produces spores
Spores dispersed by wind and water
3. Sheath Blight:
Fungus infects sheaths and culms
Fungus colonizes and produces sclerotia
Sclerotia survive in soil and infect new plants
4. Panicle Blight:
Fungus infects panicles
Fungus colonizes and produces spores
Spores dispersed by wind and water
5. Root Rot:
Fungi infect roots
Fungi colonize and produce spores
Spores dispersed by water
6. Stem Rot:
Fungi infect stems
Fungi colonize and produce spores
Spores dispersed by wind and water
7. Tungro:
Viruses transmitted by insect vectors (leafhoppers)
Viruses replicate and spread within plant
8. Bacterial Blight:
Bacteria infect leaves and stems
Bacteria colonize and produce exopolysaccharides
Bacteria dispersed by water and insect vectors

Management:

Cultural Controls:

1. Crop rotation
2. Sanitation
3. Irrigation management
4. Fertilization
5. Pruning

Chemical Controls:

1. Fungicides (e.g., azoxystrobin, propiconazole)
2. Bactericides (e.g., copper-based products)
3. Insecticides (e.g., imidacloprid)

Resistant Varieties:

1. Blast-resistant varieties
2. Leaf Spot-resistant varieties
3. Sheath Blight-resistant varieties

Integrated Pest Management (IPM):

1. Monitoring
2. Forecasting
3. Combination of cultural, chemical, and resistant variety controls

Biological Controls:

1. Biofungicides (e.g., Trichoderma)
2. Bioinsecticides (e.g., Beauveria bassiana)

Would you like information on:

1. Disease management strategies for specific rice varieties?
2. Resistance breeding programs for rice?
3. Biological control agents for rice diseases?
4. Economic impact of rice diseases?
5. Other?