COLLECTION, ISOLATION AND MORPHO-MOLECULAR CHARACTERIZATION OF ENTOMOPATHOGENIC FUNGI, METARHIZIUM RILEYI (FARL.) INFECTING FALL ARMYWORM, SPODOPTERA FRUGIPERDA (LEPIDOPTERA: NOCTUIDAE)

Abstract

The present study focuses on collection, isolation and identification of entomopathogenic fungi infecting fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) from various agroclimatic zones of Karnataka. A total of six fungal isolates belonging to the genus Metarhizium were collected and isolated from dead fall armyworm larva showing mycosis. Macroscopics features revealed whitish colony, with colony diameter ranging from 2.11 – 5.23 cm, with rough colony texture raised at the centre. Microscopic features revealed ovoid, aseptate, 2 x 3 µm (2–4 x 2–3 µm) conidia arranged in parallel chains and forming dry divergent clusters. Further, molecular confirmation of the fungi using Internal Transcribed Spacer (ITS5 and ITS4) confirmed that they belong to M. rileyi species with similarity or identity indexes of 99 %, and which was further confirmed, inferring the phylogenetic tree obtained using MEGA software with bootstraps values up to 97 % to the reference strains from the NCBI. Further, the pairwise distance matrix revealed little or no genetic divergence among the collected isolates. These identified entomopathogenic fungi (EPF) can be further used for eco-friendly management of the invasive pest fall armyworm.