My Mphil Power Point Presentation


Published on


Published in: Education, Technology
1 Like
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

My Mphil Power Point Presentation

  3. 3. INTRODUCTION Rice (Oryza sativa L.) is one of the most important crops of the world both in terms of area (152 mha) and production (585.6 mt) and major food crop for Asia. Rice is not only a major staple but also exports commodity since last ten years (Siddiq, 2002). Sixty percent of world population depends on paddy, the byproduct of rice milling rice husk and bran are used a cattle and poultry feed. Rice is main food source for more than 60 per cent population in the country. Chhattisgarh is famous as ‘Rice Bowl’ in India. Origin of Rice Archaeologists of India have found charred grains of rice in Mohenjodaro of ancient Indus civilization. Apart from it, rice grains dating back to 2000 B.C. has been found in excavations of Lothal and Rangpur in Gujarat. Rice grains were also obtained at archeological sites of Japan, China, Korea and Thailand indicating its culture in ancient era. However rice is not mentioned in Bible. Evidence indicates that it was cultivated in Nile Valley around AD 640. Alexander, the great Greek Conqueror brought rice from India during his invasions. His teacher and Philosopher, Aristotle called the rice as Oryzon and mentioned in his botanical records. Thus rice was introduced first in Europe by Alexander. Indicia rice’s were carried by seafaring traders to Malaya and Java and later to Sri Lanka in 543 B.C.
  4. 4. Table 1. Major pathogens of paddy Disease Causal organism Symptoms Country from which disease was first reported Fungal diseases Blast of paddy Pyricularia oryzae. Cavara Leaf spot, leaf blast, neck blast Italy Brown spot Drechslera oryzae / Helmininthosporium oryzae Seedling, bright brown, leaf spot, leaf blight, sesame spot pecky rice, black sheath rot Cosmopolitan Bunt Tilletia horridea Tak. Sticky spores, stunted appearance Japan False smut Green smut Claviceps oryzae sativa Ustilagenoidea virens Grains into large green mosses India Udbatta disease Ephelis oryzae Syd. Incense stick like panicles, black ring India Stack burn Trichococomis padwickii Stack burn, seedling blight, pnk kernel, leaf spot Louisiana and Texas Leaf smut Entyloma oryzae Leaden black coloured spots -
  5. 5. Bacterial disease Bacterial leaf blight of paddy Xanthomonas compestris. Closon pv. oryzae. Small water soaked lesions - Viral disease Tungro disease Rice tungro virus Syn. Interveinal chlorosis Mild. Mottling, yellowing, stunting - Nematodal diseases Ufra disease Ditylenchus angustus Buttler. Withering and death of seedlings, chlorosis. India White tip Aphelenchoides besseyi Infected seeds, nematodes lie in quiescent stage beneath half of the seeds -
  6. 6. Table 2. Details of paddy production in Karnataka YearYear Production (in million tonnes)Production (in million tonnes) 1990-911990-91 74.2974.29 1991-921991-92 74.6874.68 1992-931992-93 72.8672.86 1993-941993-94 80.380.3 1994-951994-95 81.8181.81 1995-961995-96 76.9876.98 1996-971996-97 81.7381.73 1997-981997-98 82.5482.54 1998-991998-99 86.0886.08 1999-20001999-2000 89.6889.68 2000-012000-01 84.9884.98 2001-022001-02 93.0893.08 Source : http: //
  7. 7. In Karnataka, paddy is grown in Shimoga, Chikmagalur, Chitradurga, Raichur, Mandya, Dakshina Kannada, Belgaum and Mysore which occupies 14.83 lakh hectares. Among that 10.71 lakh hectares of irrigated and 4.12 lakh hectares under rainfed condition. The annual production amount 38.47 lakh tonnes in the year 2000-01 accounts an average of 2520 kg/hectare. Karnataka stands 5th position in paddy production followed by Tamil Nadu, Andhra Pradesh, Maharashtra and overall India. Rainfall plays an important role in getting good yield and also in blast development. Heavy rainfall and relative humidity ≥ 90% influences blast at high rate (Kapoor, 2002). Shimoga district had an total geographic area of 8,47,784 hectares comprising 2,76, 855 hectares of forest, 1,01,605 hectares under non agricultural usage and remaining 4,69,324 hectares under cultivation of various crops. A total rainfall of 1703 mm is recorded between May to October months of 2006. The district paddy occupies 1,33,436 hectares comprising 28.43% of land under cultivation (Statistical Department, DC Office, Shimoga).
  8. 8. Origin of Pyricularia oryzae Pyricularia oryzae causal organism of leaf spot, leaf blast and neck blast symptoms and is first reported from Italy (Cavara, 1891 and Gangopadhyay, 1983). Rice blast occurs in 80 rice growing countries causing considerable yield reduction. The disease is believed to have occurred in Japan as early as 1704. The causal organism was however identified almost 200 years later in Italy in 1891. In India the disease was first reported in Tanjavore district in 1918. Nearly 30 fungal diseases affect rice in India of these blast is one of the most significant diseases since crop damage can be as high as 70-80%.
  9. 9. Fig. 1. Disease cycle of rice blast disease
  10. 10. Fig. 2. Mode of infection A - Attachment of Conidia to the plant surface B - Germination of conidium by sending out a short germ tube. The apical end of the germ tube extends and form a ‘Hook’ C - Formation of nascent appresorium D - Melanin layer forms in the appressorial cellwall during the maturation of infectious stage E - Driven by turgor pressure peg is forced through the plant cuticle to infect leaf F - Formation of intracellular ‘Bulbous’ hyphae G - Spread of the infection followed by conidiation
  11. 11. Map 1. Study area Shimoga district
  12. 12. Map 2. Shimoga district forest map
  13. 13. Map 3. Shimoga district Land use / Land cover map
  14. 14. REVIEW OF LITERATURE Vijaya and Balasubramaniyan (2002) reported the significant difference among the dates of sowing in both the years (1996 and 1997) of experimentation for PDI (percent disease incidence) and grain yield maximum reduction in diseases incidence was observed, when the crop was transplanted on 27th July from the nurseries of early on 30th June followed by the nursery sow on 15th July. Maximum grain yield was obtained from the crop grown with the nursery sown on 30th June. Kapoor et al. (2002) have analyzed 13 years (1984-1996) weather data revealed that the number of days with RH of ≥ 90% (47 and 27 days) during July to September, number of rainy days in a week and cloudiness was most critical factor in the development of rice blast epidemics during blast years of 1984 and 1992. Misra et al. (1997) have found the essential oil of Callistemon lanceolatus recorded, inhibitory activity against the germination of Magnoporthe grisea at 3000 ppm. The mycelial growth was however completely inhibited by only at 8000 ppm, nevertheless, 8000 ppm registered complete inhibition for specifically to stored grain pathogens of rice.
  15. 15. AIMS AND OBJECTIVES  Survey and collection of paddy blast diseased material.  Cultural characteristics and conidial diversity of Pyricularia oryzae Cavara. in Shimoga district.  Pathogenicity study of Pyricularia oryzae on host plants.
  16. 16. CONTROL AND MANAGEMENT OF BLAST In the present day fungicides play an important role in disease management, most of the early fungicides with low biochemical specificity. The fungicides are usually inorganic chemical constituents like copper oxychloride, aretan, ceresan, hinosan, kasumin, deuter, brestanol, organomercuric and organo sulphuric derivatives were least effective in control of the blast. Gangawane (1997) found Kitazin-P is effective fungicide for P. oryzae. Dubey (1997) found Tricyclazole efficacy against blast was superior over the control of neck and node infection. Vidyasekaran et al. (1997) developed powder formulation of Pseudomonas fluorescence for control of blast. In test a seed treatment and foliar spray in four field trials is effectively control the disease and increased grain yield. Chakraborty and Rao (1990) eliminated seed borne pathogens including P. oryzae by mandatory quarantine hot water treatment of 54°C for 30 min. with 6 h spore soaking was tried against naturally infected seeds.
  17. 17. MATERIALS AND METHODS Methods 1. Survey and Collection of Paddy Blast Material a. Survey i. Geography Shimoga is one of the twenty seven revenue district of Karnataka state in India. It is situated in the midsouth western part of the state. The district is situated between 13° 27" and 14° 39" N latitude and between 74° 38" and 76° 4" E longitude. The geographical area of the district as per survey of India 8439.3 sq.kms. Shimoga district divided into seven revenue administrative bodies called taluks, viz., Bhadravathi, Hosnagar, Sagar, Sorab, Shikaripur, Shimoga and Thirthahalli.
  18. 18. ii. Topography The Shimoga district clearly divided into two equal parts depending upon physiographic factors. The eastern part of the district comprises of Bhadravathi, Shimoga and part of Shikaripur taluk. This region generally known as Maidan(plane land) and absence of rich forest. The western part of the district having Thirthahalli, Sagar, Sorab, Hosanagar and part of Shikaripur taluk known as malnad (hilly tract), this region lies in the part of Western Ghats of this region having moist, ever green forest belt. The district slopes from west to east. The general elevation is 529 to 640 MSL. 2.Isolation of P. oryzae from Diseased Material Before isolating a fungal pathogen from diseased material, the tissue should be examined for fruiting bodies and mycelium. Most of fungal pathogens attacking aerial parts of the plant body readily sporulate on the host, if kept moist at a suitable temperature, making isolation of pathogen easier. If spores are present on the diseased surface, a few spores may be shaken loose over a Petri plate containing wet blotter (Aneja, 2007).
  19. 19. Standard Blotter Method The blotter method is used widely, since it is simple and inexpensive means of detecting pathogens of leaves for fungi, which readily form mycelial growth on leaves. This method provides optimum conditions for a number of fungi. The disease infected rice leaf discs were plated on two layers of moist blotter discs kept in 9 cm plastic petridishes at equidistant, that each plate contains 5 to 8 discs, these plates were incubated for 5 days under 12h/12h under normal lab conditions. The occurrence of associated mycoflora with P. oryzae were identified on fifth day using stereo-binocular microscope (Agarwal and Sinclair, 1993). Preparation of potato dextrose agar
  20. 20. Method of inoculation For this purpose, following procedures are adopted, Agar plant culture of the pathogen is selected out and take freshly sterilized culture medium, in which culture is to be inoculated. To the sterilized media a pinch of antibiotic was added to avoid the bacterial contamination and it was poured into the sterilized glass petriplates. After solidifying of the media, the P. oryzae culture present on the incubated leaf material was taken in a needle and it was inoculated into the centre of the petriplate near the flame. All these procedures are done in aseptic condition in the laminar air flow chamber. Inoculated petriplates were incubated in a incubation chamber at 20 to 40°C for 5 to 7 days.
  21. 21. 3. Pathogenicity Study of P. oryzae on Host Plant Phylloplane is a natural habitat on leaf surface which supports heterogenous population comprising both pathogens and non pathogens. There are two methods viz., 1. Serial dilution plate method and 2. Leaf impression method Here serial dilution plate method was conducted to confirm the pathogenicity test.
  22. 22. FINDINGS Table 3. Land use pattern of the study area during Kharif season (June to October), 2007 TalukTaluk Area of cultivationArea of cultivation PaddyPaddy Forest (inForest (in hectares)hectares) BhadravathiBhadravathi 42,55142,551 20,97220,972 18,23918,239 HosnagarHosnagar 17,87317,873 12,24612,246 35,02735,027 SagarSagar 26,26126,261 16,54816,548 66,12566,125 ShikaripurShikaripur 49,97249,972 31,15331,153 40,17340,173 ShimogaShimoga 45,33845,338 23,83423,834 42,89242,892 SorabaSoraba 44,69944,699 30,68430,684 26,66726,667 ThirthalliThirthalli 25,67225,672 16,82616,826 47,73747,737 TotalTotal 2,29,7332,29,733 1,52,2631,52,263 2,76,8552,76,855
  23. 23. Table 4. Temperature (in centigrade) and relative humidity (%) of the study area during kharif season (June to October), 2007 MonthsMonths Temperature (Temperature (°°C)C) Relative HumidityRelative Humidity (RH) (%)(RH) (%) MinimumMinimum MaximumMaximum JuneJune 18.0018.00 34.2534.25 94.0094.00 JulyJuly 17.0017.00 32.5032.50 93.5093.50 AugustAugust 16.2516.25 31.7531.75 90.0090.00 SeptemberSeptember 17.5017.50 33.5033.50 92.0092.00 OctoberOctober 17.2517.25 34.5034.50 92.0092.00 NovemberNovember 18.5018.50 30.0030.00 91.5091.50
  24. 24. Table 5. Area of paddy cultivated under irrigated and rainfed conditions during Kharif season (June to October), 2007 TalukTaluk Rain fedRain fed IrrigatedIrrigated BhadarvathiBhadarvathi 3,9523,952 17,02017,020 HosnagarHosnagar 6,2666,266 5,9805,980 SagarSagar 12,80212,802 13,45913,459 ShikaripurShikaripur 11,86611,866 19,28719,287 ShimogaShimoga 7,3917,391 16,44316,443 SorabaSoraba 8,9608,960 21,72421,724 ThitrthalliThitrthalli 3,5883,588 13,23813,238 Source :
  25. 25. Table 7. Leaf spot observation in the field Taluk August 2007 September 2007 October 2007 No of spot/ leaf Lesion length Avg. (mm) No of spot /leaf Lesion length Avg. (mm) No of spot /leaf Lesion length Avg. (mm) Bhadravathi 2 3 6 4 2 3 2 3 2.50 1 4 7 3 2 1 4 5 3.00 3 5 4 9 5 3 2 3 3.25 Hosnagar 10 8 8 6 8 6 4 6 6.00 9 6 10 12 5 8 8 7 7.00 11 10 9 8 9 6 8 7 7.50 Sagar 9 7 8 6 4 6 7 5 5.50 8 5 7 9 6 4 8 5 5.75 8 7 4 5 8 6 5 6 6.25 Shikaripur 2 4 2 5 3 4 2 1 2.50 3 5 2 1 3 2 4 5 3.50 4 3 1 2 1 6 4 5 4.00 Shimoga 6 4 3 5 6 4 1 2 3.25 8 6 5 3 6 4 2 3 3.75 7 5 3 2 1 6 4 7 4.50 Soraba 2 4 5 3 1 3 2 2 2 8 2 4 3 4 5 3 1 3.25 3 4 1 6 6 4 3 2 3.75 Thirthalli 7 4 6 5 6 5 3 4 4.50 5 8 9 6 10 8 3 2 5.75 9 13 10 11 8 4 9 3 6.00
  26. 26. Table 8. Colony characters of the isolates of P. oryzae Taluks Isolate Colony Characters Type Zonation Shape Colour Diameter (mm) Dry weight (mg) Bhadravathi Po1 Subaerial Indistinct Irregular Grey 23 59 Po2 Subaerial Indistinct Irregular Grey 31 86 Hosnagar Po3 Aerial Distinct Circular Dull white 52 140 Po4 Aerial Distinct Circular Dull white 58 152 Sagar Po5 Aerial Distinct Circular Dull white 48 96 Po6 Aerial Distinct Circular Dull white 50 136 Shikaripur Po7 Subaerial Indistinct Irregular Blackish 22 55 Po8 Subaerial Indistinct Irregular Blackish 28 82 Shimoga Po9 Subaerial Distinct Circular Grey 30 85 Po10 Subaerial Distinct Circular Grey 24 62 Soraba Po11 Subaerial Indistinct Irregular Dull white 26 78 Po12 Subaerial Indistinct Irregular Dull white 22 57 Thirthalli Po13 Aerial Distinct Circular Grey 46 92 Po14 Aerial Distinct Circular Grey 42 88
  27. 27. Table 9. Cultural characters of fourteen isolates of P. oryzae collected from different geographical regions (Taluks) of Shimoga Characters P. oryzae isolate Taluks Bhadravathi Hosnagar Sagar Shikaripur Shimoga Soraba Thirthalli Colour of Colony (reverse) Black Black Black Black Black Black Black Colony colour Greyish black Greyish white Greyish white Greyish black Greyish white Greyish white Greyish white Colony appearance ++ ++++ ++++ ++ +++ ++ +++ Branching pattern (Angle) Left Left and Right Left and Right Left Right Left Left and Right Formation of septum in the branch near origin Indistinct Distinct Distinct Indistinct Distinct Distinct Distinct Shape of conidia Obclavate Pyriform Pyriform Obclavate Pyriform Obclavate Pyriform Colour of colony (reverse): Black /White Colony colour: Blackish grey / Dull White Colony appearance: ++ Less feathery, +++More feathery , ++++Maximumfeathery Branching pattern: Right angle / Acute angle Shape of conidia: Obclavate / Pyriform
  28. 28. Field showing blast symptoms at Hosanagar Infected blades Infected sheaths Injured blades PLATE - I
  29. 29. A close view of blast lesion An enlarged view of blast lesion PLATE - II
  30. 30. Brown spots Tillers showing brown spots Sheath with reddish brown spots Early stage symptoms showing leaf blade yellow PLATE - III
  31. 31. Appresorium formation in P. oryzae Characteristic conidia of P. oryzae PDA culture of P. oryzae Neck blast : Lesions on panicles Spots on rice stalks PLATE - IV
  32. 32. RESULTS AND DISCUSSION Paddy (Oryza sativa L.) is the major food crop in the world today. It is the major agricultural crop growing in 14.82 lakh hectares in Karnataka with an output of 37.34 million tonnes and also a major export commodity fetch a foreign exchange of 3,174.15 crores. South Africa is the major buyer of Indian rice. India ranks second among major rice growing countries followed by China (Singhal, 2003). Blast disease is caused by P. oryzae is the most destructive cause serious losses in yield due to epyphytotics of the disease have been recorded in different regions. Hosanagar, Sagar and Thirthahalli has an severe incidence. It has been found to take a heavy toll, bringing about almost 30 to 50% loss of the crop. It is due to low night temperatures, hilly malnad climate and heavy rainfall. Blast made its impact more on kharif paddy than the rabi paddy. The loss caused due to blast is negligible in rabi. Early records shows heavy incidence of blast in Shikaripur and Bhadravathi taluks. Now it was over to malnad part of the district comprising Thirthahalli, Sagar and Hosanagar taluks. It is rarely occur on panicles resulting in infertile chaffy grains leading heavy loss to mankind.
  33. 33. In the study area, occurrence of major pathogenic fungus shows variation in their incidence at different regions due to edaphic factors. Study area is divided into irrigated and rain fed conditions. This major pathogenic fungi is more prevalent in rain fed conditions than irrigated one. In kharif, 2007, the study area receives an 159 to 1243 mm rainfall, temperature was between 16 to 34°C and relative humidity 89 to 94 % recorded. The highest annual rainfall recorded in Hosanagar followed by Thirthahalli and Sagar with 4672, 3805 and 2684 mm respectively. The economy of the study area is mainly based on agriculture and 66.27% of the cultivable land under paddy cultivation. The paddy cultivation having two seasons viz., February to May (summer or rabi) and August to November (rainy or kharif). The paddy having two cultural practices i.e., under irrigated and rainfed conditions. The plain land of the study area (Shimoga, Bhadravathi and part of the Shikaripur taluk) under irrigation having two seasons.
  34. 34. In malnad region (Thirthahalli, Sagar, Sorab, Hosanagar and part of the Shikaripur taluk) under rainfed condition. Jyothi, Jaya and Diamond Sona, Ankur Sonum and Sonamasuri are the major cultivars in the study area. The yield was 2.2 to 2.5 tonnes per hectare. The leaf spot observation in field during the study period reveals the development of blast epidemics from August to October was most severe in October or a month before harvest. Since the disease always prefer to occur at tillering or grain setting stages resulting in heavy yield loss. 2 to 8 leaf spots per leaf of minimum 1 mm recorded in Bhadravathi and maximum 9 mm recorded in Hosanagar. The average size of brown spots between 2 to 7.5 mm. The blotter tests screening of pathogenic fungi during a month before harvesting showed its associated organisms like Penicillium notatum, Aspergillus niger, Fusarium moniliformae and Cercospora lunata were observed.
  35. 35. After 5 days of incubation on blotter and pathogenic colony of organism screened and inoculated on fresh PDA culture, for cultural characteristics. The cultural plates observed for cultural characteristics like colony colour (reverse), colony colour, colony appearance, branching pattern, formation of septum and shape of conidia among 14 isolates from 7 taluks of Shimoga district and they are tabulated for their diversity. Colony characters like types, zonation, shape, colour, diameter and dry weight’s are tabulated. Among 14 isolates of 7 taluks of Shimoga district and their diversity would be known. The spore suspensions of pure culture is injected to healthy leaf for disease symptoms reveal P. oryzae at 10-4 concentration show similar symptoms to naturally diseased material is determined. Therefore, pathogenic fungi grow robustly on 10-4 concentration spore suspension evidenced that P. oryzae is the causal organism of the paddy blast disease.
  36. 36. CONCLUSION Rice production not only boosts for our economy, but also provides food security to the nation. Our GDP is completely dependent on agricultural source. Rice is a crop, mainly affected by bacterial, fungal and viral diseases. But the extent of loss caused by fungal diseases are high and desirable. Earlier days, blast epidemic was severe in almost malnad regions. Now it is concentrated over hilly, high rainfall, humid conditions. Hosanagar, Sagar and Thirthahalli taluks recorded high blast occurrence, where plain (maidan) region recorded BLB followed by Udhbatta disease at high extent. Blast can be controlled by good cultural practices like early sowing to escape or to break life cycle of blast, proper forecasting methods, uneconomic alternate hosts (grass species) eliminated by weeding, chemically by the application of carbendazim and hinosan. By using resistant varieties, more application of FYM instead of urea, seed treatment with powder formulations of Pseudomonas fluorescence, hot water treatment at 54°C for 30 min. with 6 h spore soaking was tried against naturally infected seeds, by use of eco-friendly based neem based formulations and by using antifungal botanicals like Vinca rosea, Lantana camara, Ocimum tenuliform, Solanum melongina, Azadirachta indica, Polyalthia longifolia, Aegle marmelos and Datura metel.
  37. 37. REFERENCES Agarwal, V.K. and J.B. Sinclair. 1993. Principles of Seed Pathology, pp. 37. Agrios, G.N. 2005. Plant Pathology, 5th ed., Elsevier Academic Press, London, 463-466. Aneja, K.R. 2007. Experiments in Microbiology, Plant Pathology and Biotechnology, pp. 438. Anwar, A., G.N. Bhat, S.M. Bhat and F.A. Khan. 2007. Bio-inoculants and Herbal Effect in Management of Blast Disease, Magnaporthe grisea of Rice. Environment and Ecology, 25S(3) : 652-655. Debjani, M., M. Manasi and S.N. Tiwari. 1997. Toxic Effect of Volatiles from Callistemon lanceolatus on Six Fungal Pathogens of Rice. Indian Plant Pathology, 50(1) : 103-105. Gangawane, L.V. 1997. Management of Fungicide Resistance in Plant Pathogens. Indian Plant Pathology, 50(3) : 305-315. Gowda, S.S. and K.T.P. Gowda. 1985. Epidemiology of Blast Diseases of Rice. Indian Plant Pathology, 38 : 143-144. Lingam, R.A. 1966. Spore Dispersal in Pyricularia oryzae Cav. Indian Plant Pathology, 19 : 76-81. Mishra, A. and A. Bohra. 2005. Diseases of Cereals caused by Fungi, Plant Pathology. Agrobios., Jodhpur, 402-405.
  38. 38. Murulidharan, K. and G. Venkatarao. 1990. A Simple Method of Forecasting Outbreak of Rice Blast. Indian Plant Pathology, 33(4) : 560-564. Purohit, S.S. 2006. Microbiology, Fundamentals and Applications, pp. 969. Rajan, S.S. 2001. Practical Manual of Microbiology, pp. 50. Raju, R.A. 2000. Glimpses of Rice Technology. Agrobios. (India), Jodhpur, 1-7, 176-177. Ranjith, D.R.J. 2000. Project Lifescape. Four diseases of paddy. Resonance, 93-95. Rao, M.B.K. and M.J. Louis. 1988. Conidium Ontogeny in Pyricularia. Indian Journal of Mycology an Plant Pathology, 18(1) : 78-79. Rawte, C., A. Baghel and G.K. Awadhiya. 2007. Effect of Insect Feeding on Rice Grain Discolouration. 2nd Asian Congress of Mycology and Plant Pathology, Osmania University, Hyderabad, pp. 303 Saikia, U.N. 1991. Combating Rice Blast through Chemicals. Indian Plant Pathology, 44(1) : 40-44. Sharma, P.D. 1991. Microbiology, 24-25. Singh, S.K. and Srivastava Seema. 2006. Text Book of Plant Pathology. Campus Books International, New Delhi, 242-246. Sridhar, R. 1967. Production of Indole Acetic Acid by Pyricularia oryzae. Indian Phytopathology, 20, pp. 379.
  39. 39. Subramanian, C.V. 1989. Hyphomycetes, Taxonomy and Biology. Academic Press, London, Vol. 1 and 11, 22-23, 194-195, 218- 224. Sundarajan, S. 2001. Deuteromycetes Introduction to Fungi. Anmol Publications Pvt. Ltd., New Delhi, 151-153, 256-258. Tiwari, S.N. and M. Manasi. 1992. Toxicity of Polyalthia longifolia against Fungal Pathogens of Rice. Indian Plant Pathology, 45(1) : 59-61. Umetsu, N., J. Kaji and K. Tamari. 1973. An Enzyme Immunoassay for the Detection of Tenuazonic Acid, A Toxin from the Rice Fungal Pathogen Pyricularia oryzae. Agri. Biol. Chem., 37, pp. 451. Velazhahan, R., M.L. Jeeva, P. Narayanaswamy and P. Vidyasekaran. 1997. Development of Powder Formulation of Pseudomonas fluorescence for Control of Leaf Blast. Plant Pathology, 46 : 291- 297. Vijaya, M. and K.A. Balasubramaniyan. 2002. Influence of Time of Planting on Blast Disease Incidence. Journal of Mycology and Plant Pathology, 32(2) : 1-252. Yashoda, H.R. 2006. Biological Control of Blast. International Journal of Plant Sciences, 1(1) : 99-100.