Application of a nanoformulation based on essential oil against Ephestia kuehniella larvae: Characterization and bioactivity

This study aimed to produce and characterize solid lipid nanoparticles containing the essential oil (SLN-EO) of Ziziphora clinopodioides Lam. The preparation was carried out using the high shear homogenization and ultrasound method. The biological activities of the prepared nanoformulation were evaluated against Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) larvae under laboratory conditions. The particle size of SLN-EO was estimated to be under 150 nm (polydispersity index, PDI < 0.2) and zeta potential was negative. Morphology of nanoparticles was in globular form as demonstrated by transmission electron microscopy analysis. The loaded essential oil (EO) in SLN was calculated as 92% using the filtration-centrifugation method. The fumigant toxicity of EO as SLN formulation against E. kuehniella larvae was three times greater than that of pure EO. Similar results, but to a lesser extent, were obtained from comparing their contact toxicities. The fumigant durability of EO was enhanced by nanoformulation for up to two weeks. The nutritional indices of larvae, including relative growth rate (RGR), relative consumption rate (RCR), and feeding deterrence (FDI), were influenced considerably by SLN-EO compared to pure EO. The findings suggested the solid lipid nanoparticles as a suitable nanocarrier for EO in sustainable control management of Mediterranean flour moth.