BIO EFFICACY OF NATIVE ENTOMOPATHOGENIC NEMATODES AGAINST MAJOR INSECT PESTS OF CRUCIFEROUS CROPS IN ASSAM

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dc.contributor.advisorBhagawati, Bhabesh
dc.contributor.authorBHARATH, AMURI
dc.date.accessioned2024-07-12T06:43:14Z
dc.date.available2024-07-12T06:43:14Z
dc.date.issued2023
dc.description.abstractA survey was conducted during the year 2020-2022 for isolation of entomopathogenic nematodes (EPNs) in cruciferous and vegetable growing areas of Jorhat district of Assam from 7 locations viz., Experimental Farm, Dept. of Horticulture, ICR Farm, AAU, Jorhat, Tea Plantations, AAU, Jorhat, Nemati Ghat, Moran Gaon, Titabor and 7 different isolates of EPN were recovered with 3.50 percent frequency of occurrence. Based on morphological and morphometric studies the isolates were identified to be Oscheius chongmingensis (EPN 1and 2), Heterorhabditis indica (EPN 3, 4and 5) and H. bacteriophora (EPN 6 and 7). Further, molecular characterization was done by amplification of ITS region of 5.8s mtDNA. The sequences of genus Heterorhabditis and Oscheius isolates were subjected to BLAST at NCBI and on the basis of aligned sequences, the isolates were identified to be Heterorhabditis indica, H. bacteriophora and Oscheius chongmingensis by using construction of phylogentic tree in MEGA 11.00. Efficacy of Oscheius chongmingensis, Heterorhabditis indica and H. bacteriophora were tested against Diamond backmoth (Plutella xylostella) and Cabbage butterfly (Pieris brassicae) under in-vitro conditions with six different concentrations of infective juveniles (IJs). With the increase in the concentration of IJs and with time of exposure, there was a corresponding increase in the mortality of the insect larvae. Heterorhabditis indica and H. bacteriophora showed 100 per cent mortality of P. xylostella and P. brassicae at 96 h of exposure with highest concentration of IJs/larva (i.e. 300 IJs/larva) as compared to O. chongmingensis (50.00 % mortality). The LD50 values of both the EPNs decreased when exposure period was increased. A pot experiment was also conducted to study the efficacy of two best EPNs viz. H. indica and H. bacteriophora against P. xylostella taking different doses viz. 200, 400 and 600 IJs/ pot with another treatment with water as control. H. indica exhibited maximum mortality at 600IJs after 72hrs of exposure and was found to be at par with the treatment with H. bacteriophora. The effective EPN species has to be further tested under filed conditions to identify the proper doses and method of delivery.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810211870
dc.language.isoEnglish
dc.subNematology
dc.themeBIO EFFICACY OF NATIVE ENTOMOPATHOGENIC NEMATODES AGAINST MAJOR INSECT PESTS OF CRUCIFEROUS CROPS IN ASSAM
dc.these.typePh.D
dc.titleBIO EFFICACY OF NATIVE ENTOMOPATHOGENIC NEMATODES AGAINST MAJOR INSECT PESTS OF CRUCIFEROUS CROPS IN ASSAM
dc.typeThesis
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