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Udbatta Disease

Symptoms  
  • A white mycelial mat ties panicle branches together so that panicle emerge as single, straight, dirty coloured, cylindrical rods much resembling an agarbatti or udbattta, hence the name. 
  • White mycelium and conidia form narrow stripes on the flag leaves along the veins before the panicles emerge.  No grains are formed on the affected ear.
  • The diseased plants produce distorted earheads later.  Infection of the seeds is initiated at the time of emergence of the panicle
  • It is reported to occur in severe forms in many parts of South India, including Madurai district in Tamil Nadu, Wynaad in Kerala and Kollegal and South Kanara districts in Karnataka. 
Distorted panicle with white mycelium and conidia Panicle emerge as straight dirty coloured cylindrical rods as udbathi
Distorted Panicle with
White Mycelium and
Conidia
Panicle Emerge as Straight
Dirty Coloured Cylindrical
Rods as Udbathi

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  Identification of pathogen
Ascomycete of euphelis oryzae

Perfect Stage: Balansia oryzae – sativae. Hashioka. (Subdivision: Ascomycotina; Order: Sphaeriales; Family: Hypocreaceae). The perfect stage of the fungus is an Ascoycete, Balansia oryzae-sativa. 

Disease Cycle:

  • The fungus is seed-borne externally and systemic. 
  • The presence of lustrous grayish white films of fungal growth in young leaves of the infected seedlings suggest the entry of the pathogen during germination of the seeds. 
  • As no grains are obtained from aggected heads, diseased seeds are not important in perpetuation of the disease.
  • The fungus has been recorded on the grasses Isachne elegans, Cynadon dactylon, Pennisetum sp., and Eragrostis tenuifolia and they serve as collateral hosts. 
  • The disease incidence is less severe on very early and late sown crops.

Factors favoring disease development

  • Presence of the bacteria on leaves and in the water or those surviving in the debris left after harvest
  • Warm temperature and high humidity
  • Early stage of planting from maximum tillering to panicle initiation
Ascomycete of Euphelis
Oryzae
microscopic view of fungus Ephelis oryzae
Microscopic View of
Fungus Ephelis Oryzae

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Management Strategies  
  • Use disease free seeds for sowing.
  • Seed treatment with Captan or Thiram.
  • Hot water treatment of the seeds at 50-540 C for 10 minutes before sowing gives effective control of the disease. 
  • Solar treatment of seeds is effective in killing the pathogen carried in the seeds, if any. 
  • It is also advisable to avoid using seeds from fields where the disease is noted. 
  •  Removal and destruction of diseased panicles in field.

Seed Treatment with Captan Solar treatment of seeds
Seed Treatment with
Captan
Solar Treatment of Seeds
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