Sheath rot( Sarocladium oryzae )

Symptoms

• The disease appears at the time of earing.
• This disease is more common in cases of late planting in the first crop.
• Sheath rot affects the upper leaf sheaths, which encloses young panicles.
• The lesions are oblong to irregular in shape, and are 0.5-1.5 cm long.
• The lesions may have brown margins and grey centre or uniformly grayish brown.
• Gradually lesions enlarge and cover entire sheath.
• Whitish mycelium can be seen in the centre of the lesions on the inner side of the affected sheath.
• The developing panicles are choked within the rotten sheath. Sometimes partial emergence is also noticed.
• The resulting grains will be chaffy or poorly filled, shriveled and discoloured.

Management

• Destroy crop residues immediately after harvest to reduce inoculum level.
• Manage pests such as stem borer and nematodes.
• Apply 50% more potash than recommended dosage in split application.
• Ensure good weed control.
• Use certified and disease free healthy seeds.
• Hot water treatment of seed at 52^oC for 8-10 minutes.
• Ensure balanced application of NPK fertilizers.
• Use of resistant varieties such as Aruna, Athira, Asha, Resmi, Nila, Remya, Rajani, and Arathy.
• Follow optimum plant spacing.
• Application of Gypsum is found to reduce disease incidence.
• Seed treatment with Pseudomonas fluorescens (10 g/litre of water for 1 kg of seed)
• prophylatic spraying of Pseudomonas fluorescens (20 g/litre of water) is effective in preventing the incidence of the disease.
• Apply neem cake coated urea.
• Soak seed for 12 to 16 hours in Carbendazim 50 WP (2 gram / kg of seed per litre of water).

Chemical Control

Sl.No	Generic Name	Trade Name	Color code	Dosage/litre	Knapsack Sprayer (Capacity 10L)	Dosage/acre (200 L)	Dosage/hectare (500 L)	Remarks
1	Mancozeb 75 WP	Devidayal M-45, Dhanuka M 45, Dhanuka M-45, Dithane, Dithane M-45, Hilthane, Hindustan M 45, Indofil M 45, Izeb M-45 Manzate, Luzen-45, Macoban, Macoban M-45, Mancosaan, Mancosaan M-45, Maneb Manzane, M-Guard, Savour M 45, Tata M-45 Eurofil-NT, Uthane M-45, Veera, Zinthane;	Green	3 g/ litre of water	30 g	0.6 kg	1.5 kg
2	Carbendazim 50 WP	Bavistin, Benfil, Bengard, Benlate, Benmain, Bensaan, Carben, Carziim50, Dhanustin, Dhanustin 50 WP, Fungiguard, Gancarzin50, Glizim, Mintho, Tagstin, Tiara, Zoom	Green	1 g/ litre of water	10 g	200 g	500 g
3	Hexaconazole 5 EC	Alert Creeper, Contaf, Corazole, Danzole, Force 5C, Hexaan, Hexacone, Hexadhan, Hexamax, Hexan, Hexazole, Mainex EC, Sitara, Strike, Titan, Topper, Topper plus EC, Xantho	Blue	1 ml/ litre of water	10 ml	200 ml	500 ml

Extremely Toxic

Highly Toxic

Moderately Toxic

Slightly Toxic