Parasitic competence of Telenomus remus: Response to age-structured and scale-protected eggs of Spodopterafrugiperda

Telenomus remus Nixon (Hymenoptera: Scelionidae) is an important egg parasitoid of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Understanding the influence of host egg age and physical barriers on parasitism by T. remus is essential for optimizing its mass rearing and augmentative biological control program against this invasive pest. The aim of study was to know whether and to what extent age and presence of scales on host eggs influence the parasitism by T. remus. We investigated the parasitism potential of T. remus on 24- and 48-h-old eggs (with and without scales) of S. frugiperda. Significant differences were observed in daily and total parasitism when eggs of S. frugiperda with varying age were offered to parasitoid females. The parasitism was comparatively more on 24-h-old as compared to 48-h-old eggs. However, presence or absence of scales on the eggs had no significant impact on these parameters. There were no significant differences in adult emergence and proportion of the females in progeny (sex-ratio) from 24- and 48-h-old eggs offered to the parasitoid for parasitism. Further, the adult emergence was also not influenced by presence of scales on eggs. The present findings will help in mass rearing of this parasitoid and developing augmentative biological control programme under field conditions for this invasive pest.