Exploring insecticidal properties and acetylcholinesterase inhibition by three plant essential oils against the cheese skipper Piophila casei (Diptera: Piophilidae)

Abstract

Piophila casei is a highly problematic pest in the food industry, specifically ham processing. However, given the specific requirements of the food industry, there is an urgent requirement for environmentally friendly, more efficient and safer approaches to manage the P. casei. This study aimed to assess the fumigant and contact toxicity of three plant essential oils (EOs) against P. casei by examining their impact on P. casei acetylcholinesterase (AChE) activity and investigating the potential mode of action of their primary constituents using molecular docking and molecular dynamics simulations. The results indicate that Mentha canadensis EO exhibited substantial contact toxicity against P. casei, with the LC50 of 2.98 μL/cm2 after 48-h contact with second instar larvae and an IC50 of 4.99 μL/cm2 for inhibiting pupation in third instar larvae over a 5-day period. Moreover, M. canadensis and Jasminum sambac EOs demonstrated their significant fumigant toxicity, with LT50 of 7.06 and 17.55 h, respectively, at an air concentration of 0.5 mL/L. Among the three EOs, M. canadensis EO displayed the most effective inhibition of P. casei AChE activity, while the other two EOs also exhibited certain levels of activity inhibition, shedding light on the insecticidal mechanisms of EOs against P. casei. Additionally, the molecular docking and molecular dynamics simulations were employed to investigate the mechanisms of action and binding capacity of menthol and limonene, the major constituents of M. canadensis EO. The experimental validation verified the efficacy of menthol. Overall, the results demonstrate that M. canadensis EO and its components exhibit remarkable insecticidal properties and high safety profiles, rendering them suitable for insecticide deployment in pest management within the food industry.