Enhance the physicochemical properties of the citronella oil -SLNPs to improve the insecticidal activity against Spodoptera littoralis (Boisd) (Lep. Nactuidae).

The Nano-formulation of citronella essential oil (Cymbopogon nardus (L.) and their mixtures of three adjuvants (Provecta®, Top film®, and PEG600-dioleate) were studied to enhance physico-chemical properties of the Nano-formulation and improve the insecticidal effect against Spodoptera littoralis (Boisd). Characterisation of physicochemical properties of Nano-formulation was studied by calculating droplet size, polydispersity index (PDI), and Zeta-potential parameters. The results showed that the Solid Lipid Nanoparticles (SLNs) mixtures of three adjuvant mixtures had more toxic activity and stability than the Nano-formulation alone. Before storage the acidity, alkalinity (pH), and viscosity exhibited an acidic pH value in the range (4.11-5.34), whereas after three months of storage was recorded high pH, a shift in the pH on storage can indicate the instability of active substances or product under semi field-laboratory conditions. Nano-formulation of the citronella oil mixed with the three adjuvants increased the mortality percentage of S. littoralis larvae.

Enzyme inhibitory potency of nano formulation of some plant oils on the red palm weevil Rhynchophorus ferrugineus olivier.

Inhibitory effect of the tested plant oils and their nanoformulation against trypsin and chymotrypsin enzyme extracted from Rhynchophorus ferrugineus, was studies in in vivo and in vitro. In vivo inhibition, the reduction in the trypsin specific activity caused by the bulk oils was greater than that of chymotrypsin enzyme. Compared to control nanoformulation caused significant reduction in the specific activity of trypsin enzyme; however, there were no inhibition effect observed on chymotrypsin enzyme. In vitro bulk oils showed very low inhibitory effect against trypsin enzyme, while they showed strong inhibition activity against chymotrypsin with recording for ginger nanoformulation (half-maximal inhibitory concentration (IC50) =6.83 µg/ml), purple nutsedge (7.632 µg/ml), garden cress (11.52 µg/ml) and castor (16.82 µg/ml), nanoformulation of these oils showed uncompetitive type of inhibition as the Vmax and Km values changed compared to control. In conclusion, nanoformulation of the tested plant oils could be used in the integrated pest management (IPM) programs of the red palm weevil (RPW).