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         Agricultural crops :: Cereals ::Ragi diseases
 
          
            | Seedling blight/leaf blight/leaf spot: Helminthosporium nodulosum |  
            | Symptom: 
                The pathogen affects both seedling and the adult plantsMinute, oval, light brown lesions on the young leaves and become dark brownSeveral such lesions coalesce to form large patches of infection on the leaf blade. The affected blades wither prematurely and the seedlings may be killed.Linear oblong and dark brown spots appear on the leaves of grown up plants. The leaves give blightening appearance. Prominent brown to dark brown discoloration in the neck region  and followed by weakening of neck tissue that causes it to break and the ears hanging down from the plantWhile nursery infection causes heavy damage due to the seedling blight, neck infection causes heavy chaffiness and severe loss in grain yield.It is seed-borne and primary infection is through seedSecondary infection through air borne conidia and stubbles |  
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                |  | INFECTED PLANT |  | LEAF SPOT |  | SHEATH BLIGHT |  |  |  
          
            | Identification of pathogen: 
                The mycelium is intra and inter-cellular septate and light brown in colourConidia are erect or curved septate and dark brown. They are borne at the tip of conidiophoresConidiophores are thick walled cylindrical or obcavate straight or curved and light green in color and 3-10 septateThe spores germinate either through the stomata or epidermal cells.11 spores may be formed in one conidiophore MANAGEMENT: Chemical method 
                Treat the seeds with Captan or Thiram @4g/KgSpray Mancozeb @ 1.25Kg/haSpray 1% Bordeaux mixture or Copper oxy chloride or Dithane Z-78 (2g/lit. water) | 
              
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                | Conidia of Helminthosporium nodulosum |  |  
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                | Content Validator: Dr. T.Raguchandar, Professor (Plant Pathology), TNAU, Coimbatore-641003 Thanks to Dr.M.N.Budhar, Professor and Head, Regional Research Station, Paiyur- 65112
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