Study of sexual behaviour and characterization of female sex pheromone of fall armyworm Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) collected from different locations of Tamil Nadu, India

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is considered a highly destructive pest of maize. It has its origin in the tropical and subtropical regions of America and has recently invaded many agricultural regions of India. One of the struggles in managing the pest is pheromone divergence between strains and pheromone blend variation between geographically different populations. The calling pattern, copulation behaviour and mating compatibility of different populations of S. frugiperda were investigated using behavioural methods. EAG and GC-EAD were used to analyze the chemical composition of the female gland extracts and GC-MS was used to identify the active compounds. In closed arena bioassays, the virgin males' behavioural responses to the GC-EAD compounds were further assessed. Three active compounds, Z9-14:OAc, Z11-16:OAc and Z7-12:OAc, were identified as major constituents of sex pheromone extracted from rice strain FAW which were found to be feeding on maize. All three compounds triggered intense male antennation. This study provides a deeper insight into the sexual behaviour of fall armyworm which will help in the development of more efficient lure-based pest management strategies.