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Central Agricultural University, College of Post Graduate Studies in Agricultural Sciences, Umiam

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  • ThesisItemOpen Access
    Biodiversity and molecular characterization of insect pests and natural enemies of potato ecosystem in mid hills of Meghalaya
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-10) Adhikari, Mounika; Thakur, N. S. Azad
    Potato is a principal food crop as its greater yield potential along with prominent nutritive significance, it is universally recognized as ‘The king of vegetables’. Major limiting factors for the production and productivity of potato crop include both biotic and abiotic factors. Among biotic factors, Insect pests majorly infest the crop from germination to till harvest. Besides insect pests, several natural enemies and visitors harbour in potato ecosystem. Correct identification of agricultural pests is a prerequisite for the effective control of insect pests. DNA barcoding, a significant device of DNA based taxonomy is used to identify known and unknown species based on the shape of nucleotide positioning in a piece of DNA from marked species. Therefore major work was framed to study the biodiversity and molecular characterization of insect pests and natural enemies of potato ecosystem in mid hills of Meghalaya. A total of 48 insect species and one non insect were recorded. The highest number of species were in the order Coleoptera followed by Hemiptera, Diptera, Lepidoptera, Hymenoptera and Araneae with 43, 31, 12, 10, 2, 2 percent, respectively. A total of 31 insect pests, 14 natural enemies and 4 visitors were recorded. Six major insect specimens viz., Pthorimaea operculella, Thysanoplusia orichalcea, Tuta absoluta, Macrosiphum euphorbiae, Henosepilachna vigintioctopunctata, Anomala sp., were recorded as major pests of potato ecosystem in this region. The remaining 25 insect species were categorized as minor pests which belonged to 3 orders and 11 families. A total of 14 natural enemies of potato crop belonged to 5 orders and 4 families. While the common natural enemies were Chelonus sp., Coccinella septempunctata, Oenopia kirbyi and Micraspis sp. The collected insects were identified based on established taxonomic keys and on molecular basis. DNA was successfully extracted from multiple specimens of 28 insect species and molecular assays were also undertaken for presence of Wolbachia infection. The DNA barcodes were successfully developed for 26 species by sequencing partial Cytochrome oxidase I (COI) gene of mitochondrial DNA. The molecular identity of the insect species was established through NCBI BLAST. The species level identity was developed for 19 species and remaining 7 were identified up to genus level due to absence of matching molecular data at NCBI. All the analyzed sequences were deposited to International Gene Bank (NCBI) with accession numbers MT516413 to MT516440 and MT541891.The comprehensive taxonomical and molecular database developed in this study for a total of 26 species observed in potato ecosystem could be used as diagnostic guide at both morphological and molecular level.