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V. Shakeela , S. S. Hussaini

Abstract

Entomopathogenic nematodes are now well recognized as potential biological control agents against a wide range of insect pests. Although EPN inhabit the soil, their field application and success depends on soil texture and other abiotic characteristics. Information on the influence of soil variability on the efficacy of EPN is scanty and limited. In view of this, an in vitro study was carried out to examine the influence of soil types on the infectivity and persistence of Heterorhabditis indica and Steinernema carpocapsae with different foraging habits. The pathogenicity and persistence of S. carpocapsae and H. indica varied in different soil types. Virulence of S. carpocapsae PDBC EN 11 was maximum in sandy clay loam soils (I, II and III), clay, sandy clay and sandy soil (I) with 90-100% mortality of wax moth larvae, Galleria mellonella at 24h exposure whereas mortality due to H. indica PDBC EN 13.31 was maximum in soil types of sand, sandy clay, clay, silt and two types of sandy clay loam with absolute mortality within 36h post exposure. The virulence of S. carpocapsae was greater than H. indica in all soil types. Both the nematode species persisted longer in silt and silty clay soils compared to sandy and sandy clay loam soils. Soil type affected nematode infectivity and persistence differentially with lighter soil types favouring virulence and heavier soil types with higher silt fractions favouring persistence over time.

Keywords

Entomopathogenic Nematode, Soil Types, Infectivity and Persistence.

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S. S. Hussaini ¹, V. Shakeela ¹, M. H. Dar ¹

Affiliations
1 P. B. No. 2491, H. A. Farm Post, Bellary Road Hebbal, Bangalore, 560 024, Karnataka, IN

Abstract

Effect of different temperatures on infectivity and progeny production of indigenous entomopathogenic nematode isolates, Steinernema carpocapsae PDBC EN 6.11, S. abbasi PDBC EN 3.1, S.tami PDBC EN 2.1, and Heterorhabditis indica PDBC EN 6.71, PDBC EN 13.3 were studied under laboratory condition against Galleria mellonella (Linnaeus) and Agrotis ipsilon (Hufnagel) final instar larvae. All isolates caused absolute mortality of test insect larvae, and produced progeny at 25 and 32°C. Low rate of infection or no infection was observed at lower temperatures, 15 and 8°C, respectively. Time required to kill host insects by all isolates showed difference at 15, 25 and 32°C. Shortest time for mortality of A. ipsilon and G. mellonella larvae was observed at 32°C followed by 25°C. Absolute mortality of larvae was observed with all isolates after 48 and 72 hours at 25° and 32°C, whereas the same was not achieved at 15°C even after 96 hours post exposure. Progeny production of all isolates varied with reference to temperature. Irrespective of isolates, 25°C was found suitable for infection and development of nematode populations.

Keywords

Agratis ipsilon, Entomopalhogenic Nematodes, Galleria mellonella, Heterorhabditis indica, Steinernema abbasi, S. carpocapsae, S. tami, Temperature.

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M. Nagesh ¹, S. S. Hussaini ¹, H. R. Jagadish Kumar ¹, B. S. Chidananda Swamy ¹

Affiliations
1 Project Directorate of Biological Control (lCAR), Post Bag No. 2491. H. A. Farm Post. Bellary Road, Bangalore 560 024, Karnataka, IN

Abstract

Two native isolates each of Paecilomyces lilacinus (Thomson) Sams. (PDBC PL55 and PDBC PLS8) and Pochonia chlamydosporia Zare et al. (PDBC VC56 and PDBC VC57) were subjected to repeated sub-culturing for ten generations at 28 ± 1°C with intervening resting periods in refrigerated conditions to evaluate the effect on their spore viability and infeetivity. Significant decrease in spore viability was noticed from generation IX in case of P. lilacinus isolates (PDBC PLSS and 58), while, P. chlamydosporia (PDBC VCS6 and 57) isolates recorded significant reduction in spore viability from generation VII. The infeetivity of the P. lilacinus and P. chlamydosporia isolates under study were on par with each other in ail the generations, which recorded significant reduction in tenth generation. Between the spore viability and infectivity of the isolates under report, spore viability was more influenced by repeated sub-culturing than infeetivity.

Keywords

Infectivity, Meloidogyne incognita, Paecilomyces lilacinus, Pochonia chlamydosporia, Spore Viability, Sub-Culturing.

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M. Nagesh ¹, S. S. Hussaini ¹, S. P. Singh ¹, S. R. Biswas ¹

Affiliations
1 Project Directorate of Biological Control (ICAR) P.B. No. 2491, H.A. Farm P.O., Bellary Road Bangalore 560024, Karnataka, IN

Abstract

Talc and pesta granule formulations of P. lilacinus spores, obtained from solid and liquid media, at 12, 10, 8 and 6 per cent moisture levels were evaluated for their spore viability and tbeir field efficacy, singly and in combination with neem cake against ischolar_main-knot nematode, Meloidogyne incognita in the farmer's field. The preparation of P. lilacinus used in the field consisted mainly of spores. The fungus was cultured under two sets of defined conditions to produce aerial spores, i. e., cultured on sorghum grains, and submerged spores, grown in a liquid medium. Aerial spores were more robust (96, 87, 80 and 60% viability at 6, 8, 10 and 12% moisture levels, respectively, in talc formulation from sorghum grains), compared to submerged spores (83, 72,64 and 54% viability at 6, 8, 10 and 12% moisture levels, respectively, in talc formulation from liquid broth), over a period of 60 days after formulation. Talc and pesta granules of P. lilacinus, applied at 2 doses, 10 and 15 kg/ha to the ischolar_main-knot nematode infested chrysanthemum field correspondingly reduced ischolar_main gall index to 1.4-2.7, nematode multiplication rate to 1.4-2.12, and enhanced floral yield by 12 per cent depending on the dose of formulation. Further, combined use of these formulations with neem cake enhanced fungal propagules in rhizosphere to 700-1070, fungal infectivity to 32- 52 per cent and chrysanthemum flower yield (by 23-28 %) depending on the dose of formulation.

Keywords

Chrysanthemum, Field Evaluation, Formulations, Meloidogyne incognita, Moisture Levels, Paecilomyces lilacinus.

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C. Sankaranarayanan ¹, S. S. Hussaini ¹, P. SreeramaFumar ¹, R. Rangeshwaran ¹

Affiliations
1 Project Directorate of Biological Control Post Box No. 249 I, H. A. Farm Post, Bellary Road Hebbal, Bangalore 560024, Karnataka, IN

Abstract

The efficacy of Verticillium chlamydosporium Goddard cultured on different substrates such as sorghum grain, rice grain, broken wheat, maize grain and wheat bran, was tested against meloidogyne incognita (Kofoid and White 1919) Chitwood 1949 with tomato cv. Pusa Ruby under potted condition. All the substrates favoured the multiplication of V. chlamydosporium and enabled the fungus to suppress the galls, egg masses and nematode population. The degree of suppression of nematode by V. chlamydosporium varied with the substrates used and the per cent parasitization of egg masses and eggs of M. incognita ranged between 39 to 70 and 51 to 89, respectively. Verticillium chlamydosporium cultured on sorghum grain applied @10glplant as well as Sglplant was found to be superior to other substrates in terms of parasitization of egg masses (70 and 89.3 %) and eggs (63 and 69 %), respectively. A significant increase in growth of tomato plants was observed with V. chlamydosporium treated plants.

Keywords

Biological Control, Meloidogyne incognita, Tomato, Verticillium chlamydosporium.

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C. Sankaranarayanan ¹, S. S. Hussaini ¹, P. Sreerama Kumar ¹, R. D. Prasad ¹

Affiliations
1 Project Directorate of Biological Control, Post Bag No. 2491, H. A. Farm Post, Bangalore 560024, Karnataka, IN

Abstract

In vitro experiment was conducted to study the effect of different fungal filtrates against Meloidogyne incognita (Kofoid and White) Chitwood, and M. javanica (Treub) Chitwood. Significant nematode mortality was observed in all the culture filtrates and as the exposure time increased there was an increase in mortality of nematodes recorded. The culture filtrates of Trichoderma harzianum Rifai (PDBCTH 2) and T. koningii Oudem recorded 100 per cent mortality within 24 h of exposure in both the nematode species. Culture filtrates of different fungi under study, except T. harzianum (PDBCTH 7 and PDBCTH 8) against M. incognita and PDBCTH 8 against M. javanica, recorded 100 per cent nematode mortality at 96 h of exposure.

Keywords

Culture Filtrate, Gliocladium spp., Meloidogyne incognita, M. javanica, Trichoderma spp.

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