R. Rangeshwaran ¹, J. Raj ², P. Sreerama Kumar ¹

Affiliations
1 Biological Control (ICAR), H. A. Farm Post, Hebbal, Bellary Road, Bangalore, 560 024, Karnataka, IN
2 Department of Agricultural Microbiology, University of Agricultural Sciences, Bangalore, Karnataka, IN

Abstract

Five chickpea (Cicer arietinum) endophytic bacteria, identified as Erwinia herbicola, Enterobacter agglomeraus. Bacillus megaterium and Bacillus sp. and Bacillus circulans were tested for intrinsic antibiotic resistance in order to see if endophytes showed variation in resistance to antibiotics. The resistance pattern was compared with two rhizospheric bacteria viz. Psendomonas fluoresceus and B. subtilis in order to see if the susceptibility of endophytes differed with that of bacteria isolated from rhizosphere. The endophytes seemed to be less resistant to antibiotics. B. circulaus was susceptible to all antibiotics tested except amoxycillin (10μg). However B. megaterium and Bacillus sp, and E. agglomeraus showed some resistance, P. fluorescens and B. subtilis showed resistance to a wide range of antibiotics indicating that they could be better competitors in the rhizosphere. Preliminary screening was done to monitor B. megaterium and Bacillus sp. by using the observed antibiotic resistance. Out of the 25 ischolar_main/stem/leaf tissues tested, 10 tested positive for the presence of B. megaterium and 11 for Bacillus sp. However, they coutd not be reisolated from the stem tissue, 3 and 2 of the leaf samples showed presence of B. megaterium and Bacillus sp., respectively.

Keywords

Antibiotics, Endophytic Bacteria, Resistance Pattern.

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P. Sreerama Kumar ¹, Leena Singh ¹, Habeeba Tabassum ¹

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

Abstract

Polyethylene glycol (PEG 6000) at six different concentrations (1, 2, 3, 4, 5 and 6% w/v) in Sabouraud dextrose broth influenced both quality and quantity of the biomass of Hirsutella thompsonti (nonsynnematous) and H. thompsonti var. synnematosa (synnematous) in submerged culture. Whereas the number of colony-forming units (CFU), wet and dry weights of both nonsynnematous and synnematous strains increased, pellet number and size decreased with the increasing concentration of PEG in the medium. However, there was no significant effect of the chemical on conidial germination, although conidiation of biomass of both strains was slightly delayed. The intended aim of getting more of hyphal fragments and less of mycelial pellets with the chemical was achieved as reflected in the maximum CFU obtained with 6 per cent PEG in H. thompsonii (360.53 × 10³/ml) and H. thompsonti var. synnematosa (237 × 10³/ml). Compared with the respective controls, the highest level of PEG produced 6 and 2.8 times less number of fully-formed pellets in the nonsynnematous and synnematous strains, respectively.

Keywords

Biomass, Fungal Pathogen, Hirsutella thompsonii, H. thompsonii var. Synnematosa, Mass Production, Pellets, Polyethylene Glycol, Submerged Culture.

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P. Sreerama Kumar ¹, S. P. Singh ¹, C. P. Anuroop ¹

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

Abstract

The hyphomycetous fungus, Sporothrix fungorum de Hoog&de Vries was discovered affecting the coconut eriophyid mite, Aceria gllerreronis Keifer in Karnataka and Tamil Nadu in India during 1999-2000 in up to 15 per cent of coconut samples. At 2xlOs, 2xl0· and 2xl07 conidia per ml the fungus could bring' about 47.03, 92.75 and 98.29 per cent mortalities, respectively, 96h after inoculation. It was able to grow and conidiate profusely on potato dextrose agar (PDA) as well as Sabouraud dextrose agar (SDA). The diameter of the colony increased significantly between 10 and 21 days of inoculation in both the media, reaching up to 35.83 and 36.00 mm on PDA and SDA, respectively. Among three different liquid media, viz., potato dextrose broth (PDB), Sabouraud dextrose broth (SDB) and an enrichment medium (EM), EM was the best in terms of wet and dry weights (per 100 ml) as well as conidia production in both stationary (6450.3 mg, 1602.3 mg and 71.7 x 106 / ml) and shake cultures (13416.7 mg, 3402.7 mg and 83.0 x 107 / mI). The present report gives new details about S. fungorum as well as its association with the coconut mite.

Keywords

Aceria gllerrerollis, Biological Control, Coconut, Eriophyid Mite, Sporothrix fungorum.

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Sunil Joshi ¹, P. Sreerama Kumar ¹, S. P. Singh ¹

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

Abstract

Fusarium coccopllilum (Desm.) Wollenw.&Reinking was recorded as a fungal pathogen of the sugarcane whitefly, Aleuroiobus barodensis (Maskell) from Dhule and Pune areas of Maharashtra. The infection level during rainy season varied from 2.2 to 12.8 per cent. Its pathogenicity both to nymphs and pupae was confirmed. This is the first report of F. coccophiluln on sugarcane whitefly.

Keywords

Aleuroiobus barodellsis, Fungal Pathogen. Fusarium Coccopllilum. Sugarcane Whilefly

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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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