Heterorhabditis indica Isolate as a Potential Biocontrol Agent Against Cabbage Lepidopteran Pests: Integrating Morphometric, Molecular and Bio‐Efficacy Evidence

Cabbage ( Brassica oleracea var. capitata ) is an economically important vegetable crop and its productivity is severely constrained by lepidopteran pests, particularly Plutella xylostella , Pieris brassicae and Trichoplusia ni . Excessive dependence on chemical insecticides has led to resistance development and environmental problems, necessitating sustainable alternatives. This study investigated the occurrence, identification and biocontrol potential of native entomopathogenic nematodes (EPNs) from Meerut region of western Uttar Pradesh, India. Thirty composite soil samples collected from different habitats were baited with Galleria mellonella larvae to isolate EPNs. The recovered isolate was characterised by morphological, morphometric and molecular analyses, and its pathogenicity was evaluated against major cabbage lepidopteran pests under laboratory conditions. The overall occurrence of EPNs was 10%, with all isolates were recovered from orchard soils. Morphological and morphometric characterisation identified the isolate SVPUAT MO3 as Heterorhabditis indica , while principal component analysis revealed moderate morphometric differentiation with close affinity to known H. indica isolates. Molecular characterisation based on the D2–D3 expansion segments of the 28S rRNA gene revealed 99.87% similarity with H. indica strain MEX‐5, and phylogenetic analysis clustered the isolate within the H. indica clade (GenBank accession: PX062264). Results revealed high susceptibility of P. xylostella and T. ni larvae to H. indica SVPUAT MO3, with maximum mortalities of 100% at 72 h, whereas P. brassicae exhibited moderate susceptibility, with a maximum mortality of 66.67%. These findings highlight the potential of this native H. indica isolate as a promising biological control agent for inclusion into integrated pest management programmes for sustainable cabbage production.