Cinnamon essential oil loaded β-cyclodextrin/gum Arabic nanoparticles affecting life table parameters of potato tuber moth, Phthorimaea operculella (Zeller)

Abstract

Plant essential oils are considered potential natural alternatives to chemical insecticides. However, increased degradation and evaporation of essential oils on exposure to environmental conditions may affect the bioavailability of their phytocompounds and reduce their activity as bio-insecticides. Therefore, this study aimed to formulate nanocapsules of cinnamon essential oil (CEO) by lyophilization technique using mixtures of β-cyclodextrin and gum Arabic (βCD + GA) inclusion as coating materials. By measuring life table parameters, the dry nano-formulations of CEO-βCD/GA were tested for insecticidal activity against the potato tuber moth Phthorimaea operculella (Zeller). Gas Chromatography–Mass Spectrometry analysis of CEO identified cinnamaldehyde as the major volatile, followed by benzyl alcohol with eugenol and nerol detected as minor constituents. CEO-βCD/GA particle sizes were 164.43 ± 1.27 nm and 151.36 ± 1.24 nm, with PDI values of 0.11 ± 0.00 and 0.25 ± 0.00 for 5.0 and 2.5% concentration, respectively. High percentage of encapsulation efficiency was obtained, reaching 81.53 ± 0.39 and 87.39 ± 0.31 for CEO-βCD/GA at concentrations of 2.5 and 5.0%, respectively. Higher mortality rates occurred in larvae treated with 2.5 and 5.0% CEO-βCD/GA (80, 85%, respectively) compared with 45% and 65% mortality rates recorded for 2.5 and 5.0% pure CEO, respectively. When compared to pure CEO, CEO-βCD/GA had a significant negative impact on tested population parameters of life table. Our findings revealed that nanoencapsulation of CEO by loading with βCD + GA inclusion increased its insecticidal efficacy. CEO-βCD/GA nanocapsules could be effective in P. operculella integrated pest management program.