The chemical composition and biological activities of plant essential oils against Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a highly destructive insect pest that negatively affects various agricultural crops. For environmentally safe means of its control, we evaluated the effectiveness of four plant essential oils: mint, Mentha piperita, citrus lime, Citrus sinensis, lemongrass, Cymbopogon citratus, and eucalyptus, Eucalyptus camaldulensis, against S. frugiperda larvae in terms of mortality rate and their antifeedant activity. A total of 78, 73, 52 and 26 compounds were detected in EOs of C. citratus, E. camaldulensis, C. sinensis and M. piperita, respectively. A high variation in the major compounds and percentages of these compounds was: C. citratus (3,8-nonadien-2-one, 4,8 dimethyl, 23.66%), E. camaldulensis (eucalyptol, 42.21%), C. sinensis (apiol, 5.59%) and M. piperita (cubenol, 8.43%). Three different concentrations (1.0%, 3.0% and 5.0%) of each essential oil were tested against 3rd larval instar. All essential oils caused mortality, but M. piperita and E. camaldulensis were the most effective at higher concentration. At concentration of 5.0%, M. piperita caused 93.3% larval mortality after 72 h of application. Similarly, E. camaldulensis oil caused 83.3% larval mortality after 72 h with 5.0% concentration. Furthermore, at 5.0% concentration, M. piperita oil had an antifeedant activity of 80.4%, and E. camaldulensis oil showed 71.3%. The findings indicate the potential use of M. piperita and E. camaldulensis oils to control S. frugiperda. The utilization of these oils offers an environment friendly approach, which can effectively address the issue of insecticide resistance in S. frugiperda.