Blast
Blast1. Blast :
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C. O.: Pyricularia grisea
Class: Deuteromycetes
Order: Moniliales
Family: Moniliaceae
Per. Stage: Magnaporthae grisea
Symptoms:
1). Leaf blast:
• Fungus attacks all aerial parts of plants at all growth stages
• Small water soaked bluish green flecks which enlarge soon to form spindle spots with grey center of dark brown margin on leaves.
2). Nodal blast:
• Symptoms appear on nodes and glumes
• Affected nodes break up and all the plants parts above infected nodes may die.
3). Neck blast:
• After folwer/panicle emergence the fungus attacks the penduncle.
• On neck a brownish coloured spot appears, seed becomes black and shriveled
• Partial grain filling is observed in late infected panicles
• Infected panicle hangs down
Management:
• Use disease free seeds
• Seed treatment woth organomercuriales @ 2-3 g/kg of seeds or emisan (MEMC) @ 3g/kg.
• Seed treatment with captan, cabbendazim, carboxin or tricyclozole @ 2g/kg
• Seed treatment with Trichoderma viride @ 4g/kg or Pseudomonas fluorescens @ 10g/kg seeds
• Spray nursery with carbendazim or edifenphos 0.05%
• Spray the main field with edifenphos 250 ml or iprobenphos 500 ml or carbendazim 250 g or tricyclazole 400 g or thiophanate methyl 500 g or pyroquilon 500 g/ha
• Spray blasticidin (20 ppm) or kasugamycin (20 ppm) or hinosan 0.1%
• Two sprays of 0.05% carbendazim or 0.035% thiophanate methyl at boot leaf stage and flowering
stage
• Middle Gujarat transplant GR-11 or Pankhali-203 between 1st July to 1st August
• Two sprays of tricyclazole @ 0.045% of isoprothiolane @ 0.04% or procholoz @ 0.05% first at boot leaf stage and second at flowering stage.
Bacterial blight
2. Bacterial blight :
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C. O. Xanthomonas oryzae Pv. oryzae
Class: Schizomycetes
Order: Pseudomonadales
Family: Pseudomonadaceae
Symptoms:
• Seedling in the nursery show circular yellow spots in the margin, later enlarge , coalesce and cause drying of foliage “Kresek” symptoms
• In grown up plants dull, greenish, water soaked translucent lesions appear on leaf tip and margin giving marginal drying
• Several such regions may coalesce to from straw coloured brown large lesions giving blighted appearance
• Milky or plae amber colour bacterial ooze may observe on infected portions
• In severe infections, all the leaves are attacked and premature drying noticed
• In cut end of infected leaf is dipped in water, bacterial ooze makes the water turbid
Management:
• Use disease free healthy seeds
• Avoid clipping of tip of seedling at the time of transplanting
• Avoid flood irrigation
• Remove weed hosts
• Use optimum doses of nitrogenous fertilizers
• Seed soaking in ceresin 0.1% and streptocycline (3 g in 11 lit of water) for 8 hrs
• Seed soaking in agrimycin (0.025%) and wettable ceresin (0.05%) followed by hot water treatment at 52-54° C for 10 mins
• Spray streptocycline 6 g/20 lit + copper oxychloride 60 g
• Spray MEMC (Emisan, 0.2%) + streptocycline, 250 ppm
• Spray streptomycin sulphate and tetracycline combination 300 g + copper oxychloride, 1.25 kg/ha
• Use resistant varieties- TKM-6, IR-42, IR-24, Ratna, Sathi, Ambika
Brown leaf spot3. Brown leaf spot:
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C. O. Helminthosporium oryzae
Class: Deuteromycetes
Order: Moniliales
Family: Dematiacea
Per. Stage: Cochlibolus miyabeans
Symptoms:
• The disease appear first as minute brown dots, later becoming cylindrical or oval to circular
• Several spots coalesces and the leaf dries up
• The seedling die and affected nurseries can be often recognized from a distance by their brownish appearance
• Neck region becomes brown of grayish brown
• Infected grain become shriveled and discoloured
• Low percentage of germination is obtained with the infected grains.
Management:
• Destruction of stubbles and grass hosts from the field
• Use disease free seeds
• Cleaning of bunds
• Proper use of nitrogenous fertilizers
• Seed treatment with organomerculariales like Emnisan 0.2% or TMTD
• Spraying of chlorothionil @ 0.2% or mancozeb @ 0.25% or propiconazole @ 0.005%
• Growing of resistant varieties- Orissa T-141, Navagam-19
False smut or green smut 
False smut or green smut 4. False smut or green smut :
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C. O.: Ustilaginoidea virens
Class: Deuteromycetes
Order: Moniliales
Family: Dematiaceae
Per. Stage: Claviceps oryzae
Symptoms:
• The disease appears on the ears only
• Individual ovaries are transformed into large velvety green masses
• Only few spikelets in the ear are affected
• The glumes are not affected but are covered superficially by the green mass of spores
• The size of sclerotia is about 8 X 10 mm
• The infected overies become yellowish brown which releases the spores of false smut
Management:
• Field sanitation, collection and destruction of smutted ear heads from field
• Destruction of wild collateral host
• Spraying of captafol @ 0.08%, first spray at flowering stage and second spray 10 days after first spray
• Seed disinfection with copper oxychloride is reported to reduce the incidence.
Foot rot/ Sheath rot/ Stem rot/ Bakanae 
Foot rot/ Sheath rot/ Stem rot/ Bakanae5. Foot rot/ Sheath rot/ Stem rot/ Bakanae :
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C. O. Fusarium moniliformae
Per. Stage: Giberella fugikuroi
Symptoms:
• The infected seedlings in the nursery are chlorotic and plae, lean an lanky, much better taller than healthy seedling and die after sometime
• In the main field, the affected plants have tall lanky tillers and have longer internodes and aerial adventitious roots from the nodes above ground level
• The root system is fibrous and brushy
• The plants are killed before earhead formation or they produce sterile spikeletes. Pronounced rotting of basal portion of the plant
Management:
• Seed treatment with thiaram or captan or carbendazim @ 2g/kg of seed
• Proper use of nitrogenous fertilizers
Khaira disease (Zinc deficiency)6. Khaira disease of rice (Zinc deficiency):
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Symptoms:
• Disease appears 10-15 days after transplantation
• Leaves of diseases plant show chlorosis at the base
• Larger number of small brown or bronze spots appears on the lamina
• The spots get coalesce to form bigger spot and the entire leaf turns bronze coloured and dries
• Plant shows stunting
• The root growth is restricted and main root turn brown
• The finger root are destroyed
• In severe cases, plant fails to grow further
• In some cases plants recover naturally and some of them produce ears with few grains
Management:
• Two sprays of a mixture of Zinc sulphate 2 kg + 1 kg slaked lime in 400 lit of water/acre
• 1st spray give as soon as symptoms of deficiency noticed
• 2nd spray give 10 days later
• Incorporate zink sulphate 25-30 kg/ha after every three years.
