Abstract Post-harvest losses caused by insect pests pose a significant challenge to global food security and the economic sustainability of stored grains. This study aims to improve the effectiveness of Lawsonia inermis (henna) essential oil as a renewable and eco-friendly alternative to synthetic insecticides for controlling Rhyzopertha dominica. The essential oil was extracted by hydrodistillation and analyzed using gas chromatography–mass spectrometry (GC–MS), which identified major constituents such as 2-Hydroxy-1,4-naphthoquinone (lawsone), limonene, 1,8-cineole, 1,2,3-benzenetriol, linalool, and α-pinene. Three nanoemulsion formulations with surfactant-to-oil ratios (SORs) of 2:1, 2.5:1, and 3:1 were prepared and assessed for insecticidal activity and physical stability. The formulation with SOR 2.5:1 exhibited the highest toxicity and stability; under optimal sonication (20 min), it had a mean droplet size of 118.2 nm, polydispersity index (PDI) of 0.19, and zeta potential of −27.1 mV. The nanoemulsion significantly enhanced insecticidal activity compared to the bulk oil and pirimiphos-methyl, achieving a fumigant LC₅₀ of 48.8 μl l −1 air (bulk oil: 90.5 μl l −1 air; pirimiphos-methyl: 108.6 μl l −1 air) and a contact LC₅₀ of 0.30 μl cm −2 (bulk oil: 1.30 μl cm −2 ; pirimiphos-methyl: 0.85 μl cm −2 ). It also achieved 100% repellency at a concentration of 0.3 μl cm −2 . These findings demonstrate that L. inermis essential oil nanoemulsion is a potent and sustainable alternative for controlling R. dominica.
Azam et al. (Thu,) studied this question.