<b>Background and Objective:</b> In recent years, nanoemulsions have been used to target pest toxicity due to the dangers of chemical pesticides. The current study investigated the insecticidal activity of the mandarin crust oil (<i>Citrus reticulata</i>) and marigold extract (<i>Calendula officinalis </i>L.) in the form of nanoemulsions formulations and plant oil against 2nd instars larvae of <i>Spodoptera littoralis</i>. (Boisduval). <b>Materials and Methods:</b> To assess the toxicity of treatments to 2nd instar larvae, the leaf-dipping technique was used. The toxicity was recorded after one, three, five and seven days post-treatment and LC<sub>50</sub> values were calculated. <b>Results:</b> The results indicated that nanoemulsion of plant oil extracts has the highest insecticidal activity against <i>S. littoralis</i>, followed by plant oil extracts. The major constituents identified by GC-MS analysis in marigold extract and mandarin crust oil were, 6-epi-shyobunol (Longiborneol) and D-Limonene, respectively. Furthermore, at LC<sub>50</sub>, all treatments decreased AST/GOT and ALT/GPT activity, showing a significant reduction in creatinine activity when compared to control. <b>Conclusion:</b> According to the current study, the use of the nanoemulsion formulation could be useful in integrated pest management programs.
Keywords: Spodoptera littoralis; cotton leaf worm; greenhouse crop; mandarin crust oil; marigold extract; nanoemulsion formulations; pest management.