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Rebijith K.B.,Indian Institute of Horticultural Research | Asokan R.,Indian Institute of Horticultural Research | Krishna V.,Kuvempu University | Kumar N.K.K.,National Bureau of Agriculturally Important Insects NBAII | Ramamurthy V.V.,Indian Agricultural Research Institute
Florida Entomologist | Year: 2012

Aphids are one of the major challenges in the agricultural pest management programmes. A reliable, quick, accurate and life stage-independent method of identification of vectors such as Aphis gossypii Glover and Myzus persicae (Sulzer) is important with respect to virus transmission, insecticide resistance and biological control. The complex life cycles, significant polymorphism, immature taxonomy and absence of trained manpower make the identification of these pests difficult. On the other hand, molecular identification is not limited by the above factors and can be easily executed by a non-specialist with a little training. Since the mitochondrial cytochrome oxidase-1 (COI) exhibits maternal inherited characteristics and reliable inter-specific variation as compared to other molecular markers, species-specific markers have been developed using existing nucleotide differences in the COI partial sequences of both A. gossypii and M. persicae. These species-specific markers have proved to be adequate for the molecular identification of these species, and to corroborate their morphological identification. Molecular diversity analyses using both mitochondrial and nuclear markers showed that neither A. gossypii nor M. persicae has as much genetic variability as expected. An outcome of this investigation is the development of a technique that is useful for the quick identification of A. gossypii and M. persicae, a critical factor in understanding the epidemiology and management of the potyviruses, and also in facilitating quarantines of these 2 pests. Source


Rebijith K.B.,Indian Institute of Horticultural Research | Asokan R.,Indian Institute of Horticultural Research | Kumar N.K.K.,National Bureau of Agriculturally Important Insects NBAII | Krishna V.,Kuvempu University | And 2 more authors.
Bulletin of Entomological Research | Year: 2013

Rapid, precise and timely identification of invasive pest insects such as aphids is important and a challenge worldwide due to their complex life cycles, parthenogenetic reproduction, sex and colour morphs. In this respect, DNA barcoding employing a 658 bp fragment of 5′ region of the mitochondrial cytochrome oxidase I (CO-I) gene is an effective tool in addressing the above. In the present study, we employed CO-I for discriminating 142 individuals representing 32 species of aphids from India. Sequence analyses revealed that the intraspecific and interspecific distances ranged from zero to 3.8% and 2.31 to 18.9%, respectively. In addition, the study also showed for the first time the prevalence of three cryptic species, namely Brevicoryne brassicae (Linnaeus), Hyperomyzus carduellinus (Theobald) and Brachycaudus helichrysi (Kaltenbach) from India. Our work has clearly demonstrated that DNA barcoding is an efficient and accurate method for identification of aphid species (including cryptic species), an approach that potentially could play an important role in formulating viable pest management strategies, more especially biocontrol. © Cambridge University Press 2013. Source


Asokan R.,Indian Institute of Horticultural Research | Rebijith K.B.,Indian Institute of Horticultural Research | Kumar N.K.K.,National Bureau of Agriculturally Important Insects NBAII | Srikumar K.K.,Directorate of Cashew Research DCR | Bhat P.S.,Directorate of Cashew Research DCR
Entomological News | Year: 2012

Some species of mirids are major pests of cashew damaging tender shoots, inflorescence, immature nuts, and apples at various stages of development. In India, crop loss is often more than 40% in cashew alone, and the genus Helopeltis closely resembles the genus Pachypeltis. Using molecular biology tools, morphological identification is further strengthened by DNA barcoding (using COX-1) and development of species-specific markers, which helps a non-specialist to identify a species. The molecular identification of Helopeltis and Pachypeltis spp. has been corroborated with morphological identification. The investigation results help in quick, accurate, and timely identification of Helopeltis antonii and Pachypeltis maesarum, a critical factor in understanding the epidemiology of the crop losses in cashew, their management and also in quarantine. Source


Rebijith K.B.,Indian Institute of Horticultural Research | Asokan R.,Indian Institute of Horticultural Research | Kumar N.K.K.,National Bureau of Agriculturally Important Insects NBAII | Srikumar K.K.,Directorate of Cashew Besearch DCR | And 2 more authors.
Environmental Entomology | Year: 2012

Rapid, accurate, and timely identification of insects as a group is important and challenging worldwide, as they outnumber all other animals in number and diversity. DNA barcoding is a method for the identification of species in a wide range of animal taxa, which uses the 5′ region of the mitochondrial cytochrome c oxidase-I (CO-I). Yet another easy, accurate, and economical method of species discrimination is by developing species-specific markers, which produce specific amplicon for the species in question. The method is handy because it is not limited by life stages, sex, polymorphism, and other factors. Herein, we measured the usefulness of CO-I for the species discrimination of mirids in India viz. Helopeltis antonii Signoret, H. thievora Waterhouse, H. bradyi Waterhouse, and Pachypeltis maesarum Kirkaldy in their various life stages. Furthermore, our study showed the utility of species-specific markers in differentiating H. antonii (295) and H. bradyi (514) regardless of their life stages. Analysis of CO-I gene revealed <1% intraspecific divergence for all four species examined, whereas the interspecific distances ranged from 7 to 13%. This study showed that the DNA barcode and species-specific markers will aid the identification of mirids in India and will stand as a decisive tool in formulating integrated pest management (IPM) strategy, quick identification of invasive and cryptic species, haplotypes, biotypes, and other factors, if any. © 2012 Entomological Society of America. Source


Guruprasad N.M.,National Bureau of Agriculturally Important Insects NBAII | Jalali S.K.,National Bureau of Agriculturally Important Insects NBAII | Puttaraju H.P.,Bangalore University
Asian Pacific Journal of Tropical Disease | Year: 2014

Mosquitoes act as vectors for a wide range of viral and parasitic infectious diseases such as malaria, dengue, Chickungunya, lymphatic filariasis, Japanese encephalitis and West Nile virus in humans as well as in animals. Although a wide range of insecticides are used to control mosquitoes, it has only resulted in development of resistance to such insecticides. The evolution of insecticide resistance and lack of vaccines for many mosquito-borne diseases have made these arthropods highly harmful vectors. Recently, a novel approach to control mosquitoes by transinfection of life shortening maternally transmitted endo-symbiont Wolbachia wMelPop strain from fruitfly Drosophila into mosquito population has been developed by researchers. The wMelPop strain up-regulated the immune gene expression in mosquitoes thereby reducing the dengue and Chickungunya viral replication in Aedes aegypti, and also it significantly reduced the Plasmodium level in Anopheles gambiae. Here, we discuss the strategy of using Wolbachia in control of vector-borne diseases of mosquitoes. © 2014 Asian Pacific Tropical Medicine Press. Source

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