Evaluation of Some Plants for their Insecticidal Properties Against Important Lepidopterous Pests

Singh, Kamaldeep (2015) Evaluation of Some Plants for their Insecticidal Properties Against Important Lepidopterous Pests. PhD thesis thesis, CSKHPKV Palampur.

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KAMALDEEP SINGH PhD 2015 Entomology.pdf

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Abstract

Four different plants viz., Acorus calamus L., Vitex negundo L., Adhatoda vaisca L. and Dioscorea deltoidea Wall. were evaluated for their biological activities against Plutella xylostella (L.) and Helicoverpa armigera (Hub). Four different solvents viz., methanol, hexane, ethyl acetate and aqueous extracts were used for extraction. LC50 values for methanol, ethyl acetate, hexane extract of A. calamus, methanol extract of V. negundo and ethyl acetate extract of A. vasica were 2.0203, 2.2938, 2.8474, 3.4600 and 4.1709 per cent for IInd instar larvae of P. xylostella, respectively. For H. armigera, LC50 values were 1.7495, 2.3296, 3.0859, 3.7773 and 4.0296 per cent for methanol, ethyl acetate, hexane extract of A. calamus, methanol extract of A. vaisca and ethyl acetate extract of V. negundo for IInd instar larvae of H. armigera. Different plant extracts also exhibited ovicidal asctivity against P. xylostella and H. armigera and resulted in 12.62 to 79.39 and 12.74 to 53.61 per cent reduction in egg hatching, respectively. Plant extracts from polar solevents were found to be more effective in reducing the hatchability as compared to non-polar. Maximum antifeedant activity (74.63 and 80.95% feeding inhibition) was observed in hexane and methanol extract of A. calamus for P. xylostella and H. armigera, respectively. Repellent effects showed that maximum repellency was observed in methanol extract of A. calamus (51.33%) and ethyl acetate extract of V. negundo (56.89%) for P. xylostella and H. armigera, respectively. Influences of the exposure of immature stages of P. xylostella and H. armigera to sub-lethal concentartion of different plant extracts resulted in increased duration of total developmental period of P. xylostella and H. armigera as compred to untreated check. However, per cent survival upto adult formation was decreased considerably. Morphogentic abnormalities in different developmental stages such as lack of melanization in larval and pupal stages, pupal-adult intermediate, folded wing or wing less adults were also observed. Lower values for Total growth index (TGI) for P. xylostella were observed, which varied from 1.74 to 6.39 as compared to 7.16 to 13.42 in untreated check. Similar results indicating low TGI were obtained in H. armigera. Adults emerging from treated larvae in both test insects reflected reduction in fecundity as compared to those emerging from untreated larvae. However, there was non-significant effect on the fertility of the test insects. In free choice test for recording oviposition deterrent activity against P. xylostella and H. armigera, low to moderate level of deterrence was evident (13.00 to 38.22%) and (13.67 to 36.29%), respectively. Field efficacy of different plant extracts revealed that hexane extract of A. calamus was most effective against H. armigera and methanol extract of A. calamus against P. xylostella and resulted in 48.91 and 55.51 per cent reduction in population after second round of spray, respectively

Item Type: Thesis (PhD thesis)
Subjects: 500 Natural Sciences and Mathematics > 595 Arthropoda > 595.7 Insecta (Insects)
Divisions: CSKHPKV Palampur > Department of Entomology and Apiculture
Depositing User: CSKHPKV Palampur
Date Deposited: 12 May 2016 08:02
Last Modified: 18 Jul 2016 07:50
URI: http://hillagricrepository.co.in/id/eprint/1090

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