Fumigant and contact toxicity of 22 wooden essential oils and their major components against Drosophila suzukii (Diptera: Drosophilidae)

- Fumigant and contact toxicities of 22 wooden EOs and their components were assessed against Drosophila suzukii adults.
- EOs of Gaultheria fragrantissima, Croton anisatum and Illicium verum showed effective fumigant activity.
- EOs of Cinnamomum cassia and Santalum album showed effective contact toxicity.
- Methyl salicylate and trans-anethole were effective for fumigant activity.
- trans-Cinnamaldehyde and α-santalol were efective for contact toxicity.

Fumigant and contact toxicities of 22 plant essential oils (EOs) from 14 families and their constituents against the adult spotted wing drosophila (SWD), Drosophila suzukii were examined. Analyses by GC, GC-MS, and NMR led to the identification of 2, 16, 13, 4, 6, 9, and 10 compounds from Gaultheria fragrantissima, Croton anistatum, Illicium verum, Liquidamabar orientalis, Cinnamomum cassia, Rosa damasena, and Santalum album, respectively. In fumigant toxicity test, G. fragrantissima, C. anistatum, and I. verum exhibited 100, 93.8, and 95.8, and 100, 70.0, and 80.0% mortalities against the adult male and female SWD at 4.41 mg/L air, respectively. LC50 values (mg/L air) of G. fragrantissima, C. anistatum, and I. verum were 3.46, 3.67, and 3.16 against male, and 3.48, 4.31, and 4.01 against female SWD. LC50 values (mg/L air) of methyl salicylate and trans-anethole were 2.17 and 1.75 against male and 2.65 and 3.00 against female SWD, respectively. In contact toxicity tests, L. orientalis, C. cassia, R. damasena, and S. album showed insecticidal activity with LD50 values (μg/fly) of 2.64, 1.84, 3.40 and 2.18 against male SWD and of 3.74, 2.24, 8.91 and 5.61 against female SWD, respectively. 2-Phehy-1-ethanol, 3-phenyl-1-propanol, trans-cinnamaldehyde, trans-cinnamyl alcohol, and α-santalol also exhibited insecticidal activity with LD50 values of 9.79, 5.52, 2.39, 3.02 and 2.37 against male SWD and of 11.77, 7.04, 2.94, 3.32, and 3.99 against female SWD, respectively. trans-Cinnamaldehyde exhibited the highest AChE inhibition but its inhibition is likely due to a non-specific chemical inhibition. Our results indicate that wooden EOs and their components can be used as fumigants or spray-type control agents against SWD