O-09 Evaluation of the Insecticidal Activity of Jamaican Myristica fragrans Houtt. Essential Oil against Aedes Aegypti Mosquitoes

Methods: The hydro-distilled essential oil of Myristica fragrans was bioassayed against the eggs, L1–L4 larvae, pupae, and adults of the Aedes aegypti laboratory Rockefeller strain and L3 and pupae of a local field strain. Mortality was assessed at 72 hours (eggs), 24 hours (larvae/pupae) and 14 days (adults) using modified established protocols. GraphPad Prism 9 was used to conduct one-way analysis of variance followed by Tukey’s post hoc test for the immature stages (eggs, larvae and pupae) and survival curves were constructed for the adults and compared using the log-rank (Mantel-Cox) test.

Results: Our investigations revealed that the oil had minimal activity against the egg stage but displayed potentactivity against the L1 (LC50 not determined), L2 (LC50 of 26.57 ppm, 95% CI: 25.39 to 27.83), L3 (LC50 of 7.179 ppm, 95% CI: 6.644 to 7.764) and L4 (LC50 of 246.1 ppm, 95% CI: 233.7 to 259.2). As expected, the LC50 value for the non-feeding pupal stage was higher at 1090 ppm (95% CI: 1061 to 1118). The oil also displayed excellent activity against a local field strain with LC50 values of 15.82 ppm (95% CI:14.35 to 17.42) and 965.9 ppm (95% CI: 941.7 to 990.0) for L3 and pupae respectively. At concentrations of 100 and 1000 ppm, the survival rate of adult Rockefeller mosquitoes decreased from 100% to 68.3% and 53.3%, respectively. These results clearly highlight the promising insecticidal activity of the Myristica fragrans essential oil against Aedes aegypti mosquitoes.

Conclusion: The extraordinary potency of the Myristica fragrans essential oil, particularly against the larvae and adult of Aedes aegypti mosquitoes, suggests that it may be suitable for development as a mosquito insecticide, subject to further testing