Fitness of the fall armyworm Spodoptera frugiperda to a new host plant, banana (Musa nana Lour.)

Background: The fall armyworm Spodoptera frugiperda is a highly destructive agricultural pest that primarily damages maize in China. However, there were no reports of S. frugiperda damage to banana until it was observed on bananas in the wild. This suggested that banana crops may be potential hosts of the pest. To clarify the fitness and potential impact of S. frugiperda on banana, this study analysed the survival and development of S. frugiperda fed on bananas in the laboratory and constructed age-stage and two-sex life tables. Results: Larvae of S. frugiperda fed on bananas completed their life cycles and produced fertile offspring, but the larvae had eight instars and presented longer developmental duration, slower population growth, and lower body weight than maize-fed larvae. Furthermore, the banana-fed S. frugiperda had longer adult longevity and preoviposition periods than the maize-fed larvae, while the opposite tendency was observed for oviposition days and egg production. Based on age-stage and two-sex life tables, the survival probability at each stage of S. frugiperda fed on bananas was lower than that of maize-fed larvae, and banana-fed S. frugiperda showed lower reproductive capacity. Conclusions: Although banana is not an ideal host for the fall armyworm, it may be colonized by the species in situations in which the population density is high or the preferred host is scarce. Therefore, it is essential to prevent the pest from transferring to bananas and thereby increasing the number of sources of outbreaks.

Automated summary

This study found that the fall armyworm can survive and reproduce on bananas, although they prefer maize as their host. The larvae that fed on bananas had a longer developmental duration and slower population growth compared to those that fed on maize. The survival probability and reproductive capacity of the fall armyworm were lower when fed on bananas compared to maize.