Piper amalago essential oil: ovicidal activity and growth regulation effects on Aedes aegypti (Diptera: Culicidae) mosquito larvae

Abstract

The mosquito Aedes aegypti L. (Diptera: Culicidae) is the primary vector of arboviruses such as dengue, posing a significant global health challenge that is exacerbated by resistance to synthetic insecticides. This study evaluated the efficacy of Piper amalago L. (Piperaceae) essential oil as an eco-friendly, bio-rational control agent against A. aegypti. A total of 69 volatile compounds were identified, with (-)-spathulenol (10.08 %), (±)-trans-nerolidol (8.68 %), and cubebol (5.44 %) being the predominant constituents. The results demonstrated that the essential oil exhibits significant ovicidal activity, achieving 100 % inhibition at concentrations of 400 ppm and above. Additionally, the oil induced significant concentration- and time-dependent larval mortality. Exposure to 800 ppm resulted in 100 % cumulative mortality of second-instar larvae within 72 h. Probit analysis revealed a progressive decrease in the median lethal concentration (LC50) from 603.71 ppm at 24 h to 211.15 ppm by the end of the experiment. Surviving larvae showed significant relative growth inhibition and reduced adult emergence. These findings provide the first toxicological baseline for P. amalago, highlighting its ovicidal, larvicidal, and growth-regulating properties. This botanical resource represents an alternative for integrated mosquito control strategies.