Insecticidal activities of essential oil from Hedychium coronarium rhizome and its mixture of compounds against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

The fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) is an insect pest that severely affects agricultural crops worldwide. This species can generally be controlled using synthetic insecticides, but these insecticides can cause several adverse effects. Therefore, many people prefer to utilize plant-based insecticides, especially plant essential oils, as alternatives for managing insect pests. The goal of this study was to examine the insecticidal effects of Hedychium coronarium rhizome essential oil (HCEO) and its major compounds against S. frugiperda. Gas chromatography–mass spectrometry analysis of HCEO identified 1,8-cineole (39.54 %), β-pinene (25.44 %), α-pinene (12.55 %) and limonene (4.68 %) as the major compounds. The assessed LD₅₀ value for HCEO on S. frugiperda larvae via topical application at 24 h was 8.25 μg/larva. Among the major compounds tested, 1,8-cineole demonstrated the highest toxicity, followed by limonene, β-pinene and α-pinene, with LD₅₀ values of 12.65, 14.17, 23.97 and 29.12 μg/larva, respectively. Furthermore, all combinations of the four major compounds (1,8-cineole, β-pinene, α-pinene and limonene) exhibited synergistic insecticidal effects on S. frugiperda larvae. Additionally, HCEO and its major compounds had deleterious effects on the growth and development of S. frugiperda. The egg-hatching rate was also reduced. Moreover, S. frugiperda larvae treated with HCEO and 1,8-cineole presented a significant decrease in acetylcholinesterase activity. In summary, our findings suggest that HCEO and its major compounds have effective insecticidal activity for the control of S. frugiperda.