major disease of rice and their management

1. Dr.Khushboo Dubey
Assistant Professor
Dept.of Plant Pathology
JNCU,Ballia
DISEASES OF RICE

2. Nursery Diseases Main field diseases
Blast - Pyricularia grisea (P. oryzae)
Bacterial Leaf Blight - Xanthomonas oryzae
pv.oryzae
Rice tungro disease - Rice tungro virus (RTSV,
RTBV)
Brown Spot - Helminthosporium oryzae
Sheath Blight - Rhizoctonia Solani
False Smut - Ustilaginoidea virens

3. Bacterial Leaf Blight: Xanthomonas oryzae pv. oryzae
Symptom of Damage
•Seedling wilt or kresek
•Water-soaked to yellowish stripes on leaf blades
or starting at leaf tips then later increase in
lengthand width with a wavy margin
•Appearance of bacterial ooze that looks like a
milky or opaque dewdrop on young lesions early in
the morning
•Lessions turn yellow to white as the disease
advances
•If the cuts end of leaf is kept in water it becomes
turbid because of bacterial ooze

4. Management
 Biological and chemical Method
 Spray fresh cowdung extract 20% twice (starting from initial appearance of the
disease and another at fortnightly interval)
 Neem oil 60 EC 3% (or) NSKE 5% is recommended for the control of sheath rot, sheath
blight, grain discolouration and bacterial blight.
 Streptomycin sulphate 90% + Tetracylin hydrocloride 10% SP
 Kasugamycin 5% + Copper Oxychloride 45% WP

5. Rice Blast or Blast of Rice:
 Causal agent: Pyricularia oryzae (Sexual stage: Magnaporthe grisea)
 Affecting stages: All crop stages from seedling to late tillering and ear heading
stage
 It is one of the most destructive Paddy diseases. The disease affects all parts of
rice plants, mainly leaves, neck and nodes. It is expected to cause grain loss by 70
– 80%.
 Symptoms Of Rice Blast:
 Leaf Blast Of Rice – Spindle-shaped spots with grey centre and brown margin,
later causing a ‘Blasted’ or ‘Burnt’ appearance
 Neck Blast Of Rice – Greyish brown lesions on the neck, panicle breaks and fall
off
 collar Blast Of Rice – Affected nodes show black lesions which later break up .

6. Symptom of damage and D.Cycle
Leaf Collar Nodal Conidia of Pyricularia
Oryzae

7. Management
 Spray after observing initial infection of the disease,
 Carbendazim 50WP @ 500g/ha (or)
 Tricyclozole 75 WP @ 500g/ha (or)
 Metominostrobin 20 SC @ 500ml/ha (or) 47
 Azoxystrobin 25 SC @ 500 ml/ha
Nursery stage
Light infection - Spray Carbendazim
Flowering and after
At 5 % leaf area damage or 1 to 2 % neck infection spray Carbendazim or Tricyclazole @ 1 g /lit
of water.

8. Rice tungro disease : Rice tungro virus
(RTSV, RTBV)
Symptom of Damage
•Plants affected by tungro exhibit stunting and reduced tillering. Their leaves become
yellow or orange-yellow, may also have rust-colored spots.
•Discoloration begins from leaf tip and extends down to the blade or the lower leaf portion
•Delayed flowering, - panicles small and not completely exerted
•Most panicles sterile or partially filled grains

9. Management
 Physical Method
 Light traps are to be set up to attract and control the leaf hopper vectors as
well as to monitor the population.
 In the early morning, the population of leafhopper alighting near the light
trap should be killed by spraying/dusting the insecticides. This should be
practiced every day.
 Spray Two rounds of any one of the following insecticides
 Thiamethoxam 25 WDG 100g/ha
 Imidacloprid 17.8 SL 100ml/ha
at 15 and 30 days after transplanting. The vegetation on the bunds should
also be sprayed with the insecticides.

10. Rice Brown Spot:Helminthosporium oryzae
 Affecting Stages: Seedling to milky stage
 Symptoms Of Rice Brown Spot:
 Oval or cylindrical dark brown spots with a yellow halo
 Infection of florets can lead to incomplete grain filling and reduced grain
quality
 Favourable Conditions for Rice Brown Spot:
 Relative Humidity above 86 – 100%, a temperature of 16 – 36°C, and infected
seeds, weeds, and infected stubbles are some conditions favourable for
disease infection

11. Symptoms
Conidia
of Helminthospori
um oryzae

12. Chemical Management for Rice Brown
Spot:
Product Name Technical content
Tilt Fungicide Propiconazole 25%EC
Contaf Plus Fungicide Hexaconazole 5 % SC
Merger Fungicide Tricyclazole 18 % + Mancozeb 62 % WP
Godiwa Super Fungicide
Azoxystrobin 18.2% + Difenoconazole
11.4% SC

13. False Smut Of Rice-Ustilaginoidea virens
 Affecting stages: Flowering stage to maturity
 Symptoms Of False Smut Of Rice:
 Spikelets have orange or greenish-black velvety smut balls
 This leads to chaffy grains
 Favourable Conditions For False Smut Of Rice:
 A temperature of 25 – 35°C, Relative Humidity above 90%, high nitrogen
fertilization, heavy rainfall and winds are favourable conditions for false smut
infection

14. Symptoms and Identification of
Pathogen

15. Chemical Management for False Smut Of
Rice
Product Name Technical content
Amistar top fungicide
Azoxystrobin 18.2% + Difenoconazole
11.4% SC
Roko Fungicide Thiophanate Methyl 70% WP
Custodia Fungicide
Azoxystrobin 11% + Tebuconazole 18.3%
SC
Bcontrol fungicide Validamycin 3% L

16. Sheath Blight Of Rice -Rhizoctonia solani
 Affecting Stages: Tillering to heading
 Symptoms Of Sheath Blight Of Rice :
 Initially, greenish-grey oval or elliptical lesions appear on the leaf sheath near
the water level
 Later, it forms irregular lesions with a greyish-white centre and brown margin
 Favourable Conditions for Sheath Blight Of Rice :
 The disease spread is more frequent during rainy seasons. High temperature,
High Relative humidity, high nitrogen fertilization, and closer planting are
favourable conditions for sheath blight infection.

17. symptom

18. Chemical Management for Sheath Blight Of
Rice :
Product Name Technical content
Folicur Fungicide Tebuconazole 250 EC
Custodia Fungicide
Azoxystrobin 11% + Tebuconazole 18.3%
SC
Bavistin Fungicide Carbendazim 50% WP
Tata Ayaan Fungicide
Kresoxim-methyl 40% + Hexaconazole 8%
WG

19. THANKYOU EVERYONE