Larvicidal activities of hydro-ethanolic extracts of three Cameroonian medicinal plants against Aedes albopictus

摘要

Objective: To investigate the larvicidal activity of Syzygium guineense (Myrtaceae) (S. guineense), Monodora myristica and Zanthoxylum heitzii (Rutaceae) (Z. heitzii) ex-tracts against Aedes albopictus (Ae. albopictus). Methods: The larvicidal activity of the hydro-ethanolic extracts from these plant species was assessed at three different concentrations (50, 100 and 200 mg/L) on first-instar of Ae. albopictus larvae in comparison with untreated controls. Mortality rate was recorded daily for a period of 12 days. The values of LC50 and lethal time killing 50%of the tested individuals (LT50) were calculated using the log-probit analysis. Results: The root extract of S. guineense exhibited the best activity with 100%mortality after 8 days of treatment at 200 mg/L, followed by the fruit extract of Z. heitzii with 83.33%mortality at the same concentration. Nonetheless, larvae were most susceptible to the fruit extract of Z. heitzii both in terms of LC50 (39.89 mg/L) and LT50 (145.68 h). A statistically significant difference between the control and the group treated at 200 mg/L was noticed in all the extracts. Conclusions: The present study shows that the hydro-ethanolic extracts of S. guineense, Monodora myristica and Z. heitzii tested have significant larvicidal activity. These pre-liminary results are of great interest and some of these plant species can be proposed for the formulation of new bioinsecticides to control Ae. albopictus populations.