Chemical Composition and Larvicidal Activity of Lavandula angustifolia Subsp. angustifolia and Lavandula dentata Spp. dentata Essential Oils against Culex pipiens Larvae, Vector of West Nile Virus

Abstract

The Culex pipiens mosquito (Diptera: Culicidae) is highly suspected to be the vector responsible for the spread of several parasitic and viral diseases. The use of synthetic insecticides is generally the preferred method of controlling these mosquitoes’ proliferation. However, it has led to resistance problems in target mosquitoes and environmental damage. Hence, diverse plant extracts could be considered as an alternative and potential source as mosquito control agents. In this study, essential oils of Lavandula angustifolia subsp. angustifolia and Lavandula dentata spp. dentata that are growing in Morocco were examined for their insecticidal effects on Culex pipiens larvae. The bioassay was performed according to a methodology inspired by the standard protocol of the World Health Organization. The mortality rate was determined after 24 hours of exposure, and probit regression analysis was used to calculate LC50 and LC90. The chemical analysis revealed that the principal compounds of L. angustifolia subsp. essential oils include linalool, linalyl acetate, geraniol, lavandulyl acetate, camphor, β-caryophyllene, terpinen-4-ol, β-myrcene, and 1,8-cineole, while the essential oil of L. dentata spp. was mainly composed of 1,8-cineole, camphor, α-pinene, trans-pinocarveol, linalool, and borneol. These volatile compounds have shown a toxic effect against Culex pipiens larvae, with lethal concentrations LC50 and LC90 being, respectively, 140 µg/ml and 450 µg/ml, for the L. angustifolia subsp. essential oil. Meanwhile, they were estimated at 2670 µg/ml and 7400 µg/ml, respectively, for the L. dentata spp. essential oil. These results suggest using essential oils of two species of Lavandula to control the Culex pipiens mosquito. It could be useful for the study of new natural larvicidal compounds.

Larvicidal and adulticidal activity of essential oils from plants of the Lamiaceae family against the West Nile virus vector, Culex pipiens (Diptera: Culicidae)

“…These effects were expected owing to the active constituents of these oils. The major components present in lavender essential oil are as determined by GC–MS in this study corresponded with the findings of previous studies ( El-Akhal et al, 2021 , Karamaouna et al, 2013 ), as did the components present in the peppermint essential oil ( Ebadollahi et al, 2017 , Mackled et al, 2019 , Samarasekera et al, 2008 ) and the rosemary essential oil ( Jafari-sales and Pashazadeh, 2020 , Zeghib et al, 2020 ). Generally, the tested three essential oils recorded chemical constituents and their insecticidal activities in accordance with the methods of several previous studies reviewed by Ebadollahi et al (2020) .…”

“…quinquefasciatus , revealing the potent larvicidal effect of peppermint oil ( Manimaran et al, 2012 ). El-Akhal et al (2021) showed that lavender oil at 800 ppm resulted in 100% larval mortality with an LC 50 of 140 ppm against Cx. pipiens larvae.…”

Larvicidal Efficacy of Fifteen Plant Essential Oils against Culex pipiens L. Mosquitoes in Egypt

“…pipiensin Egypt [7]. Some of the applied EOs in current study had insecticidal effect against some other dipteran flies;T. foenum and B. compestris [49] and M. chamomilla, P. anisum, R. officinalis [9] were effective agianst Lucilia sericata.A. sativum [11] and L. angustifolia, Cinnamomum camphora, and Allium cepa [10] inducedlarvicidal effect against the oestrid fly, Cephalopina titillator (Clark).…”

Synergistic Effect of Bioactive Monoterpenes against the Mosquito, Culex pipiens (Diptera: Culicidae)

“…The four monoterpenes evaluated through the binary mixtures in our study constitute the major constituents in many EOs, such as Rosmarinus officinalis, Mentha pulegium, and Lavandula [30][31][32]. Indeed, 1,8-cineol (a monoterpene ether) has been reported to be toxic to many insect species, including C. pipiens [21].…”