Insecticidal and acetylcholinesterase inhibitory activities of Lamiaceae plant essential oils and their major components against Drosophila suzukii (Diptera: Drosophilidae)

• Fumigant and contact toxicities of 12 Lamiaceae plant essential oils (EOs) and their components were assessed against Drosophila suzukii adults.
• EOs of Mentha piperita and Perilla frutescens showed effective fumigant activity.
• EOs of Satureja montana and Thymus zygis showed effective contact toxicity.
• Menthol and perilla aldehyde were effective for fumigant activity, and thymol and carvacrol were for contact toxicity.
• Perilla aldehyde was most active in AChE inhibitory activity of both sexes of D. suzukii.

Drosophila suzukii is recognized as an economically important pest in North America and Europe as well as Asia. Assessments were made of fumigant and contact toxicities of 12 Lamiaceae plant essential oils (EOs) and their components. The possible mode of action of the major components of the active EOs was pursued by evaluating their activities against acetylcholinesterase (AChE) of D. suzukii. Among the EOs tested, effective fumigant activity was observed with EOs of Mentha piperita and Perilla frutescens. Menthone and menthol, and perilla aldehyde were identified as major components of M. piperita and P. frutescens, respectively. LD50 (mg/L) values of M. piperita, P. frutescens, menthone, menthol and perilla aldehyde was 3.87, 2.44, 5.76, 1.88, and 0.99 against males and 4.10, 3.31, 5.13, 1.94, and 1.15 against females, respectively. EOs of Satureja montana and Thymus zygis showed effective contact toxicity. Thymol, carvacrol, and p-cymene were the most major components of these two EOs. LD50 (μg/fly) values for contact toxicity of S. montana, T. zygis, thymol, and carvacrol were 2.95, 2.93, 1.63, and 1.30 for male, and 4.59, 5.09, 2.68 and 2.60 for female, respectively. p-Cymene was not effective in contact toxicity. Fumigant and contact toxicities of the effective EOs and their major compounds were compared with those of two commercial insecticides. Among the 6 major components which showed fumigant and contact toxicity, perilla aldehyde showed most active inhibition against AChE of both sexes of SWD. Our result indicated that Lamiaceae plant EOs and their components can be used as alternatives to conventional insecticides.