Ragi Blast

symptoms ,pathogen and management

1. COLLEGE OF AGRICULTURAL TECHNOLOGY ( Affiliated to Tamil Nadu Agricultural University, Coimbatore-3 ) (Accredited to I ndian C ouncil of Agricultural R esearch, New Delhi) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 RAGI BLAST Student Course teacher Keerthana . R Dr . S. Parthasarathy 2016021017 Assistant Professor (Plant Pathology)

2. INTRODUCTION Common name : Finger millet ( Ragi ) Scientific name : Eleusine coracana Family : Poaceae Synonyms : Birds foot, African millet, Crow footed millet.

3. Finger millet ia a low cost cereal forms staple food for many African and Asian countries. It ranks fourth among the millets in the world. It is widely grown in S outh I ndia, where it is one of the major staple food of Karnataka. The total area under ragi in India is about 5 million hectares, nearly 40% of which is in Karnataka. Over 20 diseases of ragi are known, four of which are important in India. S INTRODUCTION

4. S SIGNIFICANCE Of the several fungal diseases that affect the finger millet, blast disease caused Pyricularia grisea is the most important and destructive disease. The disease was reported for the first time in I ndia, from T anjore delta of T amil N adu by Mc Rae (1920). Blast disease is very important among the constraints that affect the yield, utilization and trade of finger millet within East Africa. In Ethiopia, finger millet blast is one of the limiting factors for the production and yield loss of crop.

5. ECONOMIC LOSSES Loss of grain yield may exceed 50% (McRae, 1922). Yield losses even upto 80 to 90% in endemic areas.

6. GLOBAL DISTRIBUTION WORLD: India ( Mc Rae, 1920) Srilanka (Park, 1932) Nepal (Thompson,1941) Malaya (Burnett, 1949) Tanzania ( Kuwite and S hao, 1992) Somalia (Mohamed, 1980) Tanganika (Wallace and Wallace, 1948) Zambia ( Muyanga and Danial , 1995) Ethiopia Uganda

7. INDIA: Karnataka Tamilnadu Maharashtra Andhra Pradesh Odissa Bihar Uttaranchal

8. SYMPTOMS Infection may occur at all stages of plant growth . Young seedlings may be blasted or blighted in the nursery bed as well as developing young plants in the main field . There are three stages in disease development. L eaf blast Node blast Neck blast

9. Leaf blast : It is more severe in tillering phase . The disease is characterized by spindle shaped spots on the leaves with grey centres surrounded by reddish brown margins. Seedlings are more susceptible to leaf blast than mature plants.

10. Leaf Blast www.apsnet.org

11. L Leaf Blast agritech.tnau.ac.in

12. Percent leaf blast severity https://link.springer.com

13. Node blast: Infection on stem causes blackening of the nodal region and the nodes break at the point of infection . All the parts above the infected node die.

14. Node Blast www.agritech.tnau.ac.in

15. Neck blast : At flowering stage, the neck just below the earhead is affected and turns sooty black in colour and usually breaks at this point . In early neck infections, the entire earhead becomes chaffy and there is no grain set at all. If grain setting occurs, they are shrivelled and reduced in size . Maximum damage is caused by the neck infection.

16. Neck and finger blast www.runetwork.org

17. Percent Finger blast severity www.researchgate.net

18. PATHOGEN Kingdom Fungi Division Ascomycota Subdivision Pezizomycotina Class Sordariomycetes Subclass Sordariomycetidae Order Magnaporthales Family Magnaporthaceae Genus Pyricularia Species P. grisea ( Cke .) Sacc .(1880)

19. In Srilanka , Pyricularia grisea has been recorded on Ragi (Park, 1932). In Uganda (Hansford, 1943) and Tanzania (Wallace and Wallace, 1948) identified the pathogen as P. oryzae . In India, Ramakrishnan (1948) considered the fungus to be a race of P. oryzae . Wallace (1950) concluded as P . setariae . Thirumalachar and Mishra (1954) identified the causal organism as P. grisea . PATHOGEN

20. PATHOGEN CHARACTERS Asexual stage: Pyricularia grisea Sexual stage: Magnaporthae grisea Mycelium: It may be intra or intercellular. Hyphae: S eptate and hyaline when young, It turn brownish and may be swollen when older; The length of cells vary between 1.5 and 6.0 microns .

21. Conidiophores : Simple, septate and dark- colored at the base and lighter above. Conidia : Pyriform shape and sub-hyaline .

22. Conidia and Conidiophores of P. grisea www.researchgate.net

23. Spores: Three celled , the middle cell being broader and darker than the others; It vary in size from 19-31 microns by 10-15 microns . Chlamydospores : G lobose , thick-walled , olive brown or dark brown in color , 4 to 10 microns in diameter; It may be terminal or intercallary and may also be produced at the end of germ tubes.

24. EPIDEMIOLOGY MODE OF SURVIVAL: Persistence on alternate hosts such as Wild Eleusine spp . Digitaria spp . Setaria verticillata Persistence on collateral hosts such as Brachiaria mutica Panicum repens The fungus may also persists in plant debris and to some extent in the shriveled grains from infected ears.

25. MODE OF SPREAD The fungus spreads mainly by air-borne conidia. Primary spread: Alternate hosts such as Eleucine indica , Eleusine Africana, Digitaria spp ., Setaria spp ., Doctyloterium spp . serves as primary sources of inoculum. Secondary spread: Air-borne conidia

26. Disease cycle of Pyricularia grisea www.researchgate.net

27. FAVOURABLE CONDITIONS Cloudy skies, frequent rain and drizzles. High levels of nitrogen. Relative humidity > 90% The optimum temperature should be 25-28 ° C for pathogen germination. In the tropics, blast spores are present in the air throughout the year, thus favouring continuous development of the disease.

28. MANAGEMENT CULTURAL METHOD: Use of disease free seeds. Proper plant spacing of 40*10 cm or 30*15 cm and transplanting is advisable. Early sowing (July month) reduces the blast severity. Practicing crop rotation such as Finger Millet - Groundnut - Maize Finger Millet - Chickpea - Wheat Finger Millet -Cowpea / Pigeonpea – Sorghum.

29. Resistant varieties: CO RA (14 ) Paiyur (RA)- 2 GPU-28 GPU-45 GPU-48 L-5 Susceptible variety: Indaf 5

30. BIOLOGICAL METHOD Spray Pseudomonas fluorescens @ 2 g/lit of water. First spray immediately after noticing the symptom. Second and Third sprays at flowering stage @ 15 days interval. Seed treatment with Pseudomonas fluorescens @ 6g/Kg seed and spray the extracts of Prosopis juliflora leaf extract (10 %) Ipomoea carnea leaf extract (10%)

31. CHEMICAL METHOD Seed treatment with Captan ( Captan 50 WP) 4 g or Carbendazim ( Bavistin ) 2 g/kg of seeds. Spray any one of the fungicides such as Edifenphos ( Hinosan ) 500 ml or Carbendazim 500 g or Iprobenphos ( Kitazin ) @ 500 ml/ha. First spray immediately after noticing the symptoms. Second and third sprays at flowering stage @ 15 days interval to control neck and finger infection.

32. Foliar spray with Aureofungin -Sol 100 ppm at 50% earhead emergence followed by second spray with M ancozeb 1000g/ha 10 days later . Spraying of Zineb ( Hexathane 75% WP) 1.5 kg/ha.

33. REFERENCES: Gupta , V.K., Paul, Y.S., and Sharma Sathish , K. 2012. Fungi and Plant Diseases. Kalyani publishers, New Delhi. Rangaswami , G and Mahadevan , A. 2016. Fourth edition. Diseases of Crop Plants In India.PHI Learning Pvt Ltd., Delhi .