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Abstract Two plant products, i.e. neem (Azadirachta indica A. Juss) extract and peppermint (Mentha pipreta) oil were selected in this study to evaluate the efficiency of their three different formulations, i.e. bulk, nano-emulsion and loaded nano-emulsion against 2nd and 4th instar larvae of two lepidopterous insect pests, i.e. the cotton leafworm, Spodoptera littoralis (Boisd.) and the black cutworm, Agrotis ipsilon (Hufn.). The evaluation process included investigation the efficacy of the prepared nano formulations against the two larval instars of both species and the effect of the same formulations on some biochemical parameters in the treated insects, i.e. -amylase, invertase, trehalase, protease, alkaline phosphatase, phenoloxidae and chitinase. Also, the effects of such formulations on some bionomics were also studied. In addition, the toxic effect of neem nano formulations on albino mice as mammalian model was included in this work. At the beginning, the characterization of the obtained nano-formulations, i.e. nano-emulsion and loaded nano-emulsion using Transmission Electron Microscopy (TEM), UV spectrophotometric examination and Fourier Transforms Infrared (FTIR) showed that the nano-emulsion particles ranged between 20-90nm. The loading capacity percentages exhibited that distilled H2O was more suitable than ethanol in preparation of nano-emulsion particles. The bioassay study to measure the efficiency of the tested formulations showed that the 2nd instar larvae was always more susceptible than the 4th instar larvae against the tested formulations. For example, LC50s on 2nd instar larvae of S. littoralis for peppermint oil were 70.59, 12.23 and 21.72 ppm for bulk peppermint oil, peppermint nano-emulsion and loaded nano-emulsion, respectively. While on 4th instar these values were 80.47, 26.14 and 67.69 ppm, respectively. Toxicity index and relative potency proved that nano-emulsion was more effective than loaded nano-emulsion, while the bulk preparation was the least effective one. Results of enzymatic activities. |