Rice Blast

symptoms,pathogen and management

1. COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 Rice blast Student Course teacher Abila bose Dr. Parthasarathy . S 2016021001 Assistant Professor (Plant Pathology)

2. SYNOPSIS NAMES SIGNIFICANCE DISTRIBUTION SYMPTOMS SYSTEMATIC CLASSIFICATION PATHOGEN MODE OF SPREAD MODE OF SURVIVAL FAVOURABLE CONDITION MANAGEMENT

3. OTHER NAMES OF RICE BLAST Other names : Rice rotten neck, rice seedling blight, oval leaf spot, pitting disease, ryegrass blast and johnson spot Rice rotten neck Rice seedling blight Oval leaf spot Rice fever Richman disease

4. SIGNIFICANCE Disease cause loss upto 31-60%. Grain loss upto 70-80%. In India, the loss is 65%. In J apan, the loss is 90%.

5. DISTRIBUTION OF RICE BLAST World: China, Japan, Italy, USA and Africa. The disease was first observed in China. India: All rice cultivated states. In India, it was observed by P admanaban in 1913.

6. SPREAD OF RICE BLAST IN WORLD

7. HISTORY OF RICE BLAST The disease was first recorded in China in 1637. In Japan, it is believed to have occurred as early as in 1704. In Italy the disease called “ brusone ” was reported in 1828 and In USA in 1876.

8. HISTORY OF RICE BLAST IN TAMIL NADU It is recorded in T amil N adu in T anjore districts in 1918.

9. SYMPTOMS Leaf blast, node blast, neck blast and grain blast. Typical leaf lesions are spindle shaped - wide in the center and pointed towards the end. Large lesions usually develop grey centers with brown borders.

10. Nodal infection causes the culm to break at the infected node. Few, no seeds, or whiteheads when neck is infected or rotten.

11. Leaf blast Agritech.tnau.ac.in

12. Collar blast Geneticliteracyproject.org

13. Panicle blast Dpi.nsw.gov.au

14. Nodal blast Geneticliteracyproject.org

15. SYSTEMATIC POSITION Kingdom Fungi Division Ascomycota Class Sordariomycetes Order Magnaporthales Family Magnaporthaceae Genus Magnaporthe Species M. grisea (Hebert)

16. PATHOGEN OF RICE BLAST

17. Life cycle of Magnaporthe grisea ©https://www.researchgate.net/figure/Life-cycle-of-the-rice-blast-fungusMagnaporthe-oryzaeThe-rice-blast-fungus-

18. MODE OF SPREAD Primary infection – wind Secondary infection - water

19. MODE OF SURVIVAL Mycelium and conidia in the infected straw and seeds are important sources of primary inoculum. The seed borne inoculum fails to initiate the disease in the plains due to highsoil temperature in June.

20. FAVOURABLE CONDITION Application of excessive doses of nitrogenous fertilizers, intermittent drizzles, cloudy weather, high relative humidity (93-99%). Low night temperature (between 15-20°C or less than 26°C), more number of rainy days, longer duration of dew, cloudy weather, slow wind movement and availability of collateral hosts .

21. MANAGEMENT- RESISTANCE VARIETIES Simhapuri , Tikkana , Sriranga , Phalguna , Swarnadhan , Swarnamukhi , MTU 7414, MTU 9992, MTU 1005, Swathi , IR 64, IR 36, Sravani , Jaya, Vijaya , Ratna , RP 4-14, IET 1444, IR20, TKM 6, MTU-3 & 5 and NLR 9672 & 9674, Co 47 , IR 20 , ADT 36, ADT 37 etc.,

22. CULTURAL METHOD Remove the alternate host. Split application of nitrogen.

23. CHEMICAL METHOD Treat the seeds with Captan or Thiram or Carbendazim or Carboxin or Tricyclazole at 2 g / kg . Spray nursery with C arbendazim 25 g . Main field with Edifenphos at 0.1% or C arbendazim at 0.1 % or T ricyclazole .

24. BIOLOGICAL METHOD Seed treatment with biocontrol agent Trichoderma viride at 4 g/ kg. Pseudomonas fluorescens at 10 g/ kg of seed .

25. REFERENCES Gupta, V.K., Paul, Y.S. and Sharma Sathish , K. 2012. Fungi and Plant D isease. Kalyani Publishers, New Delhi. https://www.biologydiscussion.com/plants/plants-diseases/ rice-blast/64332. https://www.apsnet.org/edcenter/intropp/lessons/fungi/ascomycetes/pages/rice -blast.aspx.