Isolation, identification and biocontrol potential of entomopathogenic nematodes occurring in Purvanchal and Bundelkhand regions of Uttar Pradesh, India

Abstract Entomopathogenic nematodes (EPNs) are being used for the management of insect pests occurring in both agricultural and horticultural crops. But native EPNs are reasonably more efficacious in controlling insect pests than introduced EPNs species because they are adapted to local environmental conditions and insect pests. Therefore, in the present study, a survey was conducted to isolate EPNs at 4 districts of Purvanchal Region and 1 district of Bundelkhand Region of Uttar Pradesh, India, between 2016 and 2017 years. Out of 130 soil samples, EPNs were recovered from 3 soil samples (2.3%). Morphological characters examination and ITS-rDNA region revealed that the 3 EPNs such as Steinernema sp. (IIVR JNC01 strain) Steinernema sp. (IIVR JNC02 strain), and Steinernema sp. (IIVR EPN03 strain) are belonging to Steinernema siamkayai. Further pathogenicity of all these strains was tested on Galleria mellonella Linnaeus and the most effective strain was used to determine the biocontrol potential against lepidopteran and coleopteran pests of major vegetable crops in comparison to commercially available Heterorhabditis indica (NBAIIH38 strain). Results revealed that S. siamkayai (IIVR JNC01 strain) caused 100, 100, and 85%, mortality of 3rd instar larvae of Spodoptera litura Fabricius, Spilosoma obliqua Walker, and Spoladea recurvalis Fabricius, respectively. Similarly, S. siamkayai (IIVR JNC01 strain) caused 92.5% mortality of 2nd instar grubs of Myllocerus subfaciatus Gurein under laboratory conditions. The present study revealed that EPNs commonly present at Purvanchal and Bundelkhand regions of Uttar Pradesh and S. siamkayai (IIVR JNC01 strain) isolated from the Bundelkhand Region showed a good biocontrol potential against major insect pests of vegetable crops.