Efficacy of Olive Stones and Corncobs Crystalline Silica Nanoparticles (SiO2, NPs) Treatments on Potato Tuber Moths (Phthorimaea Operculella)

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.

Automated summary

In this study, SiO2 nanoparticles were prepared from olive stones and corncobs using an alkali leaching extraction method, and their morphological and microstructural properties were modified through thermal treatment. XRD showed a transition from amorphous to crystalline phase after the thermal treatment. The specific surface area and total pores volume of the SiO2 samples decreased significantly after the thermal treatment. The thermal treatment properties of SiO2 had a significant impact on the survival and development of P. opercullela larvae and pupae. SiO2 NPs prepared from crystalline silica showed less efficiency in suppressing potato tuber moth compared to those from amorphous silica powders. The effects on biological parameters varied depending on the source and concentration of SiO2 NPs. SiO2 NPs have potential as an alternative pesticide against P. opercullela, depending on their source, mesoporous structure, and concentration.