ISOLATION AND CHARACTERIZATION OF ENTOMOPATHOGENIC ...

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IV. EXPERIMENTAL RESULTS 4.1 EXPLORATION <strong>OF</strong> THE NATURAL OCCURRENCE <strong>OF</strong> INSECT MYCOPATHOGENS IN DIFFERENT ECOLOGICAL NICHES IN NORTHERN KARNATAKA Intensive and repeated survey for the occurrence of the insect mycopathogens in the northern districts of Karnataka covering different agro climate region of agricultural and forest eco-systems were made during the cropping season of 2000-01. The number of visits to each locality varied from one to five depending upon cropping system and host insect availability. The details of places, crops and periods of visits, mycopathogens and the average disease incidence of different fungi are presented in Table 5. The natural occurrence of different pathogens in Karnataka state has also been mapped in the first year (Fig. 1). Among them, Nomuraea rileyi was predominant organism followed by Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii, Cladosporium spp., Aspergillus candidus and Fusarium spp. The survey revealed the prevalence of disease caused by Nomuraea rileyi on Helicoverpa armigera, Spodoptera litura and Thysonoplusia orichalcea in different crop habitats at Dharwad, Hubli and Navalgund taluks of Dharwad district, Ron taluka of Gadag district, Belgaum, Gokak, Bailhongal and Saundatti taluks of Belgaum district. Incidence of N. rileyi on the Lepidoptera hosts to an extent of 88 per cent in soybean at Devalpur in Bailhongal taluka of Belgaum district were witnessed during August. Mycosis of S. litura to the tune of 36 per cent was recorded on blackgram grown on the bunds of paddy fields at Siraguppa during November 2000. On the same pest, ten per cent disease incidence was noticed in irrigated groundnut at Raichur during January and February. The prevalence of M. anisopliae was noticed on diamond backmoth at Hirebagewadi (Belgaum), coconut rhinoceros at Dharwad, brown plant hopper at Tungabhadra project area (Gangavati). The natural incidence of disease caused by M. anisopliae on this insect population was however meagre (0.5 to 3.5%). Verticillium lecanii prevailed only in Haveri and Uttara Kannada districts. The fungus had colonised jasmine aphid and teak skeletonizer. During the survey, the occurrence of B. bassiana was noticed on brown plant hopper in the Tungabadra project (TBP) area on ash weevil at Bailhongal, Belgaum district and red palm weevil at Bailhongal, Belgaum district and red palm weevil at Sirsi. The other mycopathogen of insect pests collected during survey were Cladosporium oxysporum on cotton, leafhopper in Dharwad and Bailhongal, Cladosporum cladosporides on castor leafhopper, teak skelitonizer and cotton whitefly, whereas 5-19 per cent incidence of C. sphaerospermum on Ligeid bug in Dharwad, Bailhongal and Bidar. Fusarium oxysporum was recorded only on homopterans in Raichur, Haveri and Uttar Kannada districts in paddy, cotton and forest ecosystem. The incidence was highest (12.39%) on A. gossypii followed by N. lugens (5.62%) and least (2.39%) on mealy bug. A small population of cotton aphids (3.89%) was mycosed by Aspergillus candidus in Dharwad district only. 4.1.1 Isolation The cadavers of insects collected during survey were brought to the laboratory and the fungi isolated on Sabouruds Maltose Agar Medium fortified with 1 per cent Yeast Extract (SMAY).
Fig. 1. Mycopathogens of insect pests collected during survey in Northern Karnataka
Page 1 and 2: ISOLATION AND CHARACTERIZATION OF E
Page 3 and 4: Chapter No. I INTRODUCTION C O N T
Page 5 and 6: Contd….. Table No. Title 14. Spor
Page 7 and 8: Contd….. Table No. Title 39. Per
Page 9 and 10: Plate No. LIST OF PLATES Title 1. M
Page 11 and 12: I.INTRODUCTION The increased use of
Page 13 and 14: II. REVIEW OF LITERATURE The variou
Page 15 and 16: The entomopathogenic fungi so far i
Page 17 and 18: Table 1. Contd….. Sl. No. Insect
Page 19 and 20: Milner et al. (2002) studied the ef
Page 21 and 22: 25°C for sporulation and biomass p
Page 23 and 24: Pathogencity of various strains/iso
Page 25 and 26: Gopalkrishnan and Mohan (2000) test
Page 27 and 28: necessary serial dilutions under ph
Page 29 and 30: Sl. No. Table 2. Details of differe
Page 31: 3.9 EVALUATION OF DIFFERENT FORMULA
Page 35 and 36: Table 5. Contd….. Month/s visited
Page 37 and 38: Table 5. Contd….. Month/s visited
Page 39 and 40: Table 5. Contd….. Mycosis noticed
Page 41 and 42: Totally eight isolates of N. rileyi
Page 43 and 44: Metarhizium anisopliae Vertucillium
Page 45 and 46: Ma 1 (Dharwad) Ma2 (Dharwad) Ma 3 (
Page 47 and 48: Table 8. Mortality caused by the is
Page 49 and 50: Helicoverpa armigera Dimond Black M
Page 51 and 52: Plate 5. The moratality of Hlelicov
Page 53 and 54: Table 11. Total biomass production
Page 55 and 56: Table 12. Total biomass production
Page 57 and 58: Table 14. Sporulation of Metarhiziu
Page 59 and 60: Mean spore yield x 10 8 /g 25 20 15
Page 61 and 62: Among the non-grain substrates, the
Page 63 and 64: Mean spore yield x 10 4 /g 35 30 25
Page 65 and 66: Sl. No. Table 19. Effect of fungici
Page 67 and 68: Per cent inhibition 100 90 80 70 60
Page 69 and 70: Sl. No. Table 21. Effect of insecti
Page 71 and 72: Out of nine insecticides, endosulfa
Page 73 and 74: Sl. No. Table 23. Effect of weedici
Page 75 and 76: Days after storage Table 25. Persis
Page 77 and 78: Table 26. Survival of Metarhizium a
Page 79 and 80: Table 28. Survival of Metarhizium a
Page 81 and 82: Sl. No. Table 29. Survival of Metar
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Sl. No. Table 30. Survival of Metar
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Per cent germination 90 80 70 60 50
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Sl. No. Table 33. Survival of Verti
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4.9 PATHOGENICITY OF Verticillium l
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Sl. No. Table 39. Per cent mortalit
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Culture grown on rice grains Harves
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Tr. No. Table 41. Per cent reductio
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Tr. No. Table 43. Per cent reductio
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The fungal spray at higher dosage (
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Table 46. Effect of wild types and
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The hyphal and conidial characters
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In an earlier experiment, bagasse w
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M. anisopliae exhibited rapid reduc
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higher mortality of aphids. The com
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14. Oil formulations proved better
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CHARNLEY, A.K. AND ST. LEGER, R.J.,
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IGNOFFO, C.M., MARSTON, N.L., HOSTE
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MULLER, E.J., 2000, Control of the
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ST LEGER, R.J., BUTT, T.M., STAPLES
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APPENDIX I Mean monthly weather dat
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Maharashtra Association for the Cul
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ISOLATION AND CHARACTERIZATION OF E
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