M. F. N. G. FARAG, A. A. DEWIDAR, MOHAMED G. SALAMA, HEND A. EL-NASHARTY, HEND MOHAMED ABD-ELMONEM, EMAN F. EBIAN, ASMAA M. A. EL-SAYD, EMAN M. GHAREEB AND MOGEDA M. ABDEL HAFEZ*
Plant Protection Research Institute, Agriculture Research Centre, Dokki, Giza 12619, Egypt *(e-mail: mogedamohammed@yahoo.com; Phone: 201128992127) ORCID: 0000-0002-1292-4548
(Received: May 12, 2025; Accepted: June 24, 2025)
ABSTRACT
Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and the glassy clover snail, Monacha cartusiana (O. F. Müller) (Gastropoda: Hygromiidae) are among the major damaging pests affecting global agriculture. The present study assessed the insecticidal potential of three plant-derived volatile oils: French lavender (Lavandula dentata), citronella (Cymbopogon nardus L.) and lemongrass (Cymbopogon citratus L.) against the fourth instars larvae of S. frugiperda and M. cartusiana adults under controlled laboratory conditions. The composition of the examined volatile oils was determined through gas chromatography (GC) analysis. The findings indicated that mortality rates of S. frugiperda and M. cartusiana increased with increasing concentrations of the tested volatile oils (2.25, 4.5 and 9%) and exposure time. Among the tested oils, 9% citronella exhibited the highest larval mortality of S. frugiperda (65%), followed by lemongrass (60%) and French lavender (55%) by day 5. Similarly, 9% citronella oil caused the highest mortality in M. cartusiana (40%) by day 21, compared to lemongrass (33.33%) and French lavender (26.67%). Based on the strong bioactivity of citronella oil, it was further selected for enzymatic bioassays, which revealed significant reductions in AST and ALT activity levels in both pests over the tested periods. 9% citronella oil caused the highest significant decrease, indicating metabolic disruption and tissue damage. By G C analysis, the major components identified in the tested oils were 1,8-cineole (44.15%) and linalool (24.79%) in French lavender oil, geranial (41.51%) and neral (29.76%) in lemongrass oil, and citronellal (34.67%) and geranial (27.09%) in citronella oil. Overall, citronella oil demonstrated the most potent insecticidal activity and may serve as an eco-friendly, plant-based alternative within Integrated Pest Management (IPM) programs targeting S. frugiperda and M. cartusiana.
Key words: Spodoptera frugiperda, Monacha cartusiana, volatile oils, enzymes