R. Rangeshwaran ¹, N. V. Vajid ¹, B. Ramanujam ¹, S. Sriram ¹, T. V. Bhaskaran ¹, Satendar Kumar ¹

Affiliations
1 National Bureau of Agriculturally Important Insects, Post Bag No. 2491, H. A. Farm Post, Hebbal, Bellary Road, Bangalore 560 024, Karnataka, IN

Abstract

Studies were carried out to evaluate the effect of adding nutrient additives to talc based formulations on the shelf life of bacteria stored under room temperature. Two organisms namely, Pseudomonas fluorescens (PDBCAB2) and Bacillus sp. (MTCC6534 - chickpea endophyte), a spore forming bacterium, were tested. A gradual increase in P. fluorescens population up to 90 days was observed in almost all the treatments that were amended with nutrients. At 90 days highest population of log 10.38 cfu g⁻¹ was noticed in talc amended with 2 per cent tryptone and glycerol. Decline in the population was observed from 90 days onwards and was rapid from 150 days onwards. At 240 days highest count of log 1 x 10^4.2 cfu g⁻¹ was obtained with formulations amended with 2% tryptone and 2% glycerol and the results indicated that 2% peptone or 2% tryptone supplemented with 2% glycerol helped P. fluorescens in its better survival. The spore forming Bacillus sp. survived well throughout the study period. At 240 days all talc formulations amended with nutrient sources showed a population of log 9.0 cfu g⁻¹ or above and the population declined to below log 7.0 cfu g⁻¹ only in non amended treatments. Slow decline started from 240 days but high cfu of log 9.30 to 9.38 g⁻¹ were noticed in yeast extract or tryptone treated treatments. Hence talc formulations that had yeast extract or tryptone supplemented with glycerol enhanced shelf life of Bacillus spp.

Keywords

Pseudomonas fluorescens, Bacillus sp, Powder Based Formulation, Talc, Shelf Life, Gram Positive, Gram Negative.

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Chandish R. Ballal ¹, Sunil Joshi ², T. V. Bhaskaran ², L. Lakshmi ¹

Affiliations
1 ICAR - National Bureau of Agricultural Insect Resources, H. A. Farm Post, Bellary Road, Bangalore 560 024, IN
2 Division of Food Processing, ICAR-Central Institute of Fisheries Technology Central Institute of Fisheries Technology, CIFT Junction, Willingdon Island Matsyapuri P.O., Cochin-682 029, Kerala, IN

Abstract

The rearing of ichneumonid parasitoids is a great challenge mainly due to the preponderance of male progeny in the continuously lab reared cultures. The issues faced in the continuous rearing of an indigenous ichneumonid parasitoid Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) were recorded and attempts were made to tackle these challenges by manipulating the rearing processes. Some of the problems could be considerably alleviated by rearing the parasitoids in larger cages measuring 0.52 × 0.52 × 0.76 m (with 5 to 8 parasitoid pairs per cage) and by placing these cages in walk-in chambers set at 26±2°C and 70±2% RH. It is a general observation that the culture deteriorates after some generations in the laboratory, but the need was felt to verify the biological parameters which are affected most due to continuous laboratory rearing. The reproductive rate and intrinsic rate of increase were significantly higher in the field collected parasitoids compared to the continuously lab reared ones indicating that bio-deterioration occurs due to continuous rearing. The study also indicated that it would be ideal to bring in wild culture after five generations in the laboratory and rejuvenation is essential after nine generations. Based on the information generated through basic studies, we aim to provide a simple protocol (including cage design) which can be adopted by insectaries or researchers interested in initiating and maintaining the culture of C. chlorideae. Measurable biological parameters are also suggested, which can be used to monitor the quality and scale of production.

Keywords

Campoletis chlorideae, Spodoptera Litura, Rearing Protocol.

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