Morphological and microstructural properties of silica (SiO 2 ) are essential factors that need to be considered during the experimental applications. In this report, SiO 2 nanoparticles (NPs) have been prepared at different concentrations from SiO 2 powder derived from olive stones and corncobs by an alkali leaching extraction method. Thermal treatment has been used to modify the morphological and microstructural properties of the extracted SiO 2 . X-ray diffraction (XRD) shows that the extracted amorphous SiO 2 has been transformed into a crystalline phase after the thermal treatment. Nitrogen adsorption-desorption measurements revealed signi cant reduction in both the speci c surface area (SABET) and the total pores volume (Vtotal) of the derived SiO 2 samples after the thermal treatment. The acquired thermal treatment properties of SiO 2 found to have high impacts on the in uence of the SiO 2 NPs on the survival and development of larvae and pupae of P. opercullela. SiO 2 NPs prepared from the crystalline silica samples exhibited less e ciency on suppressing potato tuber moth comparing to SiO 2 NPs of the amorphous silica powders. Varied effects on biological parameters including larvae mortality, pupae weight, larval and pupal development time, fecundity and fertility are also linked to the SiO 2 NPs source type and showed concentration depending manner effects. SiO 2 NPs are conditionally effective as an alternative pesticide against P. opercullela, based on their sources, mesoporous structures and concentrations.

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Morphological and microstructural properties of silica (SiO2) are essential factors that need to be considered during the experimental applications. In this report, SiO2 nanoparticles (NPs) have been prepared at different concentrations from SiO2 powder derived from olive stones and corncobs by an alkali leaching extraction method. Thermal treatment has been used to modify the morphological and microstructural properties of the extracted SiO2. X-ray diffraction (XRD) shows that the extracted amorphous SiO2 has been transformed into a crystalline phase after the thermal treatment. Nitrogen adsorption-desorption measurements revealed significant reduction in both the specific surface area (SABET) and the total pores volume (Vtotal) of the derived SiO2 samples after the thermal treatment. The acquired thermal treatment properties of SiO2 found to have high impacts on the influence of the SiO2 NPs on the survival and development of larvae and pupae of P. opercullela. SiO2 NPs prepared from the crystalline silica samples exhibited less efficiency on suppressing potato tuber moth comparing to SiO2 NPs of the amorphous silica powders. Varied effects on biological parameters including larvae mortality, pupae weight, larval and pupal development time, fecundity and fertility are also linked to the SiO2 NPs source type and showed concentration depending manner effects. SiO2 NPs are conditionally effective as an alternative pesticide against P. opercullela, based on their sources, mesoporous structures and concentrations.

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Summary The study examined the effect of nano-silica extracted from two different plant sources on the survival and development of the potato tuber moth, Phthorimaea opercullela. The silica powder was derived from two different agricultural byproducts, olive stones and corncobs. Characterization by X-ray diffraction revealed that the extracted powder has an amorphous silica phase. The nitrogen adsorption-desorption measurements revealed that both extracted and treated silica have mesoporous structure, with a specific surface area of around 300 m2/g and 270 m2/g for the silica derived from olive stones and corncobs, respectively. The silica nanoparticles (SiO2 NPs) prepared from the silica derived from olive stοnes showed higher larvae mortality, pupae weight, and larval and pupal developmental time, compared to the silica derived from corncombs. The results show that the nano-silica derived from agriculture byproducts can be as effective as the synthetic insecticide (deltamethrin) utilized in control of the potato tuber moth, with lower environmental impact in terms of preventing pesticide residue accumulation. In addition, the efficiency of SiO2 NPs applications depends on the source of the silica nanoparticles and the applied concentration to achieve the optimum results for the pest control.