Molecular analysis of Spodoptera frugipedra from India using 28S nuclear genes markers

The fall army worm Spodoptera frugipedra (J E Smith), commonly called as fall armyworm (FAW) (Lepidoptera: Noctuidae) is a highly voracious insect pest which is native to the tropical and subtropical regions of America. It is one of the most serious pests of maize in India. In this study, we have collected mainly larvae of S. frugiperda from the maize fields of across India using 28S nuclear gene as markers. The larvae exhibited sexual dimorphism in their morphological characteristics. BLAST search on Indian specimens revealed 98-99% nucleotide sequence identity with S. FAW voucher specimens from France and Western South America of either maize or rice populations. The phylogenetic relationship was inferred using IQ Tree1.6.12 built with input data of 54 sequences with 867 nucleic acid sites and using the best model BIC: F81+F Model with ultrafast bootstrap (1000 replicates) support. Phylogeny tree generated from the Spodoptera frugipedra of 28S data from this study alone did not show any major clades or differences. The present study revealed that the Indian maize populations were clustered in clade one which had a high degree of geographical representation consisting of Guadeloupe (France), and Peru (Western South America) maize/rice populations. As this pest is reported to have remarkable dispersal capacity, high reproductive capacity, absence of diapause, and wide host range, it is likely to spread to the entire country and further, neighbouring countries.