Nanoencapsulation enhances the contact toxicity of Eucalyptus globulus Labill and Zataria multiflora Boiss essential oils against the third instar larvae of Ephestia kuehniella (Lepidoptera: Pyralidae)

Abstract

The contact insecticidal activity of in natura and maltodextrin/Angum gum nanoencapsulated essential oils of Eucalyptus globulus Labill and Zataria multiflora Bioss was evaluated against the third instar larvae of Ephestia kuehniella (Lepidoptera: Pyralidae). The essential oil from E. globulus exhibited an average yield of 1.19%, and presented 1,8-cineol (59.08%) as the major component, while Z. multiflora essential oil, with an average yield of 1.5%, was characterized by thymol (26.12%) and carvacrol (25.31%) as the main components. The encapsulated particles presented spherical morphology with regular and homogeneous external surfaces, ranging from 60 to 130 nm in diameter. Laboratory bioassays estimated the contact LC₅₀ of in natura and encapsulated essential oils as 13.07 and 1.34 µL L⁻¹ for E. globulus and 1.47 and 5.87 µL L⁻¹ for Z. multiflora, respectively. The results presented here, which are probably the first to be reported, suggested that essential oil nanoencapsulation represents an efficient method for enhancing both insecticidal activity and the durability of the active ingredients for sustainable pest management.

Keywords:

• Essential oil
• nanocapsule
• Ephestia kuehniella
• bioassay
• stored product pests

Acknowledgments

The authors acknowledge the support of the Islamic Azad University of Tehran. We also would like to thank the research insectarium of the Iranian Research Organization for Science and Technology for providing Ephestia kuehniella eggs.

Disclosure statement

The authors report no conflict of interest.