Informatics Publishing Limited

K. Srinivasa Murthy ¹, R. Rajeshwari ¹, T. Venkatesan ¹, G. Ashok Kumar ¹

Affiliations
1 National Bureau of Agriculturally Important Insects, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore 560024, Karnataka, IN

Abstract

The cytochrome oxidase gene (COI) was employed to assess the genetic variation in different populations of Cotesia flavipes. Partial sequences of the COI gene for the populations from Bangalore, Hyderabad, New Delhi and Shimla were analyzed to assess the homology and the usefulness of this genetic region for phylogenetic studies. PCR using COI-F and COI-R primers amplified a product of approximately 550 bp which was similar for all the four populations. Populations were by and large similar in the COI gene sequenced and there was no variation with our sequences and those of sequences worldwide. The multiple alignments were performed for four populations which revealed similarity of the partial COI gene sequences. Comparative analysis of partial sequences of COI gene produced a phylogenetic tree. Phylogenetic analysis revealed that all our populations were in a single clade with high boot strap value, suggesting highest similarity.

Keywords

Cotesia flavipes, Cytochrome Oxidase, Genetic Variation.

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G. Ashok Kumar ¹, S. K. Jalali ¹, M. Nagesh ¹, T. Venkatesan ¹, P. Niranjana ¹

Affiliations
1 National Bureau of Agriculturally Important Insects, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore 560024, Karnataka, IN

Abstract

Artificial selection is extensively used to develop pesticide resistance in natural enemies. RAPD markers were used to estimate genetic relatedness between the parent and artificially selected hybrids of the egg parasitoid Trichogramma chilonis Ishii resistant to multiple insecticides (700ppm of endosulfan, 540ppm of monocrotophos and 20ppm of fenvalerate) and high temperature (> 40°C). Highly polymorphic markers could be identified through the primers OPF-1 and OPJ-20. RAPD marker from 15 oligomers clearly outgrouped the susceptible parent from artificially selected pesticide-resistant strains. The first group comprised the susceptible strain. The second group comprised the two subclusters, the first subcluster including the strain resistant to endosulfan and fenvalerate, multiple-insecticide resistant strain (MIRS) and high temperature resistant (HTR) strain while the second subcluster consisted of monocrotophos and HTR strains. The discriminating property of RAPD markers allowed differentiation of the resistant strain from the parental susceptible strain. Artificially selected resistant strains shared relatively high similarity (61-66%) with susceptible parent strain as per Jaccard's index.

Keywords

Trichogramma chilonis, RAPD, Pesticide Resistance, High Temperature, Genetic Relatednes.

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T. Venkatesan ¹, J. Poorani ², K. S. Murthy ¹, S. K. Jalali ¹, G. Ashok Kumar ¹, Y. Lalitha ¹, R. Rajeshwari ¹

Affiliations
1 Biological Control, Post Bag No. 2491, Bellary Road, Hebbal, Bangalore - 560024, Karnataka, IN
2 Biological Control, Post Bag No. 2491, Bellary Road, Hebbal, Bangalore - 560024, Karnataka., IN

Abstract

The Chrysoperla species (carnea-group) widely used in India in augmentative biological control programmes was found to be Chrysoperla zastrowi arabica Henry et al. The acoustic profile of the mating song of this species was analyzed and found to match that of C. zastrowi arabica, the song species characterized earlier as 'Cc5 generator'. The correct taxonomic name for this species remains to be determined as it is morphologically identical to C. sillemi (Esben-Petersen), a species already known from India. Molecular characterization of the species was also done and the DNA sequence of the ITS-2 region was deposited in GenBank (Accession No. DQ 825504, as that of C. sillemi). The implications of this finding are discussed.

Keywords

Chrysopidae, Carnea-group, Chrysoperla zastrowi Arabica, C. sillemi, India, Molecular Characterization, Song Analysis.

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G. Ashok Kumar ¹, S. K. Jalali ², T. Venkatesan ¹, M. Nagesh ², Y. Lalitha ³

Affiliations
1 Biological Control, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore, 560024, Karnataka, IN
2 Biological Control, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore, 560024, Karnataka, IN
3 Biological Control, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore, 560024, Karnataka, IN

Abstract

A strain of Trichogramma chilonis Ishii, an effective parasitoid of lepidopteran pests was developed for tolerance to three major groups of insecticides, i. e., endosulfan (organochlorine), monocrotophos (organophosphate) and fenvalerate (synthetic pyrethroid) and to high temperature (32-38°C) through selection. After 81 generations of selection, there was an increase in parasitism from 35% to 90-95% and decrease in mortality from 100% to 57-70% after 6h of constant exposure to three insecticides and high temperature. Interestingly 46.8 and 2.9 fold increase in tolerance was observed in males compared to 18.5 and 1.3 fold increase in females of MITT (multiple-insecticide and temperature tolerant) strain when exposed to endosulfan and fenvalerate sprays, respectively, while in case of monocrotophos, females and males were 465-fold and 25-fold more tolerant, respectively, than susceptible strain. At higher temperatures of 40 and 45°C, the per cent mortality of tolerant adults was 0.0 and 9.2%, respectively, compared to 59.7 and 96.1% in susceptible population after 6h of exposure at these temperatures. At high variable temperature (32-38°C), per cent mortality in MITT was 57.1 compared to 98.5% in susceptible population after 24h of constant exposure. The mean per cent parasitism at 32°C, 36°C, 38°C and at variable temperature of 32-38°C was significantly higher in tolerant strain (46.7, 45.0, 18.3 and 63.3%) compared to susceptible strain (54.0, 6.7, 0.0 and 0.0%), respectively. These studies suggest that the improved strain of T. chilonis will provide effective control of the pest even at harsh climatic conditions and under high insecticide pressure in different economically important crops.

Keywords

Egg Parasitoid, Genetic Improvement, High Temperature Tolerance, Multiple Insecticide Tolerance, Trichogramma chilonis.

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G. Ashok Kumar ¹, C. D. Srinivas Naik ¹, Prashanth Mohanraj ¹, R. J. Rabindra ¹, S. K. Jalali ¹

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

Abstract

The woolly aphid, Ceratovacuua lanigera Zehntner (Homoptera:Aphididae), assumed an epidemic proportion in Maharashtra and Karnataka in the year 2002. Presently this pest is prevalent in India in major sugarcane growing areas and it is important to find out the population differences to assess their epidemic potential. Molecular markers such as internal transcribed spacer (ITS) play an important role to bring out the population differences at the molecular level. Hence, ITS 2 region of C. lanigera was sequenced using specific primers (product size 448 bp) and the sequence was submitted to GenBank (DQ 825651).

Keywords

Bangalore Population, Ceratovacuma lanigera, ITS-2, Sequencing.

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