Essential oils are natural plant products that are very interesting, as they are important
sources of biologically active compounds. They comprise eco-friendly alternatives to mosquito
vector management, particularly essential oil nanoemulsion. Therefore, the aim of this study is
to evaluate the effectiveness of 16 selected essential oils (1500 ppm) in controlling mosquitoes by
investigating their larvicidal effects against the larvae and adults of the West Nile virus vector
Culex pipiens L. (Diptera: Culicidae); the best oils were turned into nanoemulsions and evaluated
under laboratory and field conditions. The results show that honeysuckle (Lonicera caprifolium) and
patchouli (Pogostemon cablin) essential oils were more effective in killing larvae than the other oils
(100% mortality) at 24 h post-treatment. The nanoemulsions of honeysuckle (LC50 = 88.30 ppm) and
patchouli (LC50 = 93.05 ppm) showed significantly higher larvicidal activity compared with bulk
honeysuckle (LC50 = 247.72 ppm) and patchouli (LC50 = 276.29 ppm) oils. L. caprifolium and P. cablin
(100% mortality), followed by Narcissus tazetta (97.78%), Rosmarinus officinalis (95.56%), and Lavandula
angustifolia (95.55%), were highly effective oils in killing female mosquitoes, and their relative efficacy
at LT50 was 5.5, 5.3, 5.8, 4.1, and 3.2 times greater, respectively, than Aloe vera. The results of the
field study show that the honeysuckle and patchouli oils and their nanoemulsions reduced densities
to 89.4, 86.5, 98.6, and 97.0% at 24 h post-treatment, respectively, with persistence for eight days
post-treatment in pools. Nano-honeysuckle (100% mortality) was more effective than honeysuckle
oils (98.0%). Our results show that honeysuckle and patchouli oils exhibited promising larvicidal and
adulticidal activity of C. pipiens. |
