My Mphil Power Point Presentation

KUVEMPU UNIVERSITY DEPARTMENT OF P. G. STUDIES AND RESEARCH IN

APPLIED BOTANY Jnana Sahyadri, SHANKARAGHATTA – 577 451

A Dissertation Entitled

DIVERSITY OF PYRICULARIA ORYZAE CAVARA. ON PADDY CROPS IN SHIMOGA

DISTRICT

Presented by

Mr. CHANDRASHEKAR, D.G.

Guided by

Prof. M. KRISHNAPPA

CONTENTS

1. INTRODUCTION

2. REVIEW OF LITERATURE

3. AIMS AND OBJECTIVES

4. CONTROL AND MANAGEMENT OF BLAST

5. MATERIALS AND METHODS

6. RESULTS AND DISCUSSION

7. CONCLUSION

REFERENCES

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.

Table 1. Major pathogens of paddy

Disease Causal organism SymptomsCountry 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

-

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

-

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: //raitamitra.kar.nic.in.statistics.html

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).

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%.

Fig. 1. Disease cycle of rice blast disease

Fig. 2. Mode of infection

A - Attachment of Conidia to the plant surfaceB - 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 appresoriumD - Melanin layer forms in the appressorial cellwall during the maturation of infectious stageE - Driven by turgor pressure peg is forced through the plant cuticle to infect leafF - Formation of intracellular ‘Bulbous’ hyphaeG - Spread of the infection followed by conidiation

Map 1. Study area Shimoga district

Map 2. Shimoga district forest map

Map 3. Shimoga district Land use / Land cover

map

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.

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.

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 54C for 30 min. with 6 h spore soaking was tried against naturally infected seeds.

MATERIALS AND METHODS

Methods1. Survey and Collection of Paddy Blast Materiala. Surveyi. 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.

ii. TopographyThe 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).

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

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 40C for 5 to 7 days.

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.

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 (in Forest (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

Total Total 2,29,7332,29,733 1,52,2631,52,263 2,76,8552,76,855

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 Relative Humidity Humidity (RH) (%)(RH) (%)MinimumMinimum MaximuMaximu

mm

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

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 : http://www.shimoga.nic.in.

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 2364

2323

2.50

1473

2145

3.00

3549

5323

3.25

Hosnagar 10886

8646

6.00

961012

5887

7.00

111098

9687

7.50

Sagar 9786

4675

5.50

8579

6485

5.75

8745

8656

6.25

Shikaripur 2425

3421

2.50

3521

3245

3.50

4312

1645

4.00

Shimoga 6435

6412

3.25

8653

6423

3.75

7532

1647

4.50

Soraba 2453

1322

2

8243

4531

3.25

3416

6432

3.75

Thirthalli 7465

6534

4.50

5896

10832

5.75

9131011

8493

6.00

Table 8. Colony characters of the isolates of P. oryzae

Taluks Isolate

Colony Characters

Type Zonation Shape ColourDiameter

(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

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 WhiteColony appearance: ++ Less feathery, +++More feathery , ++++MaximumfeatheryBranching pattern: Right angle / Acute angle Shape of conidia: Obclavate / Pyriform

Field showing blast symptoms at Hosanagar

Infected blades Infected sheaths Injured blades

PLATE - I

A close view of blast lesion

An enlarged view of blast lesion

PLATE - II

Brown spots Tillers showing brown spots

Sheath with reddish brown

spots

Early stage symptoms showing leaf blade

yellow

PLATE - III

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

RESULTS AND DISCUSSIONPaddy (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.

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 34C 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.

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.

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.

CONCLUSIONRice 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 54C 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.

REFERENCESAgarwal, 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.

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.

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.