Insecticidal and oviposition deterrent effects of essential oils and their constituents against the invasive pest Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)

• Plant oils and monoterpene oil constituents were tested for their ability to control Drosophila suzukii.
• Significant contact and fumigation toxicity was observed.
• Oils of Lavandula latifolia and avocado were the most effective whole oils tested.
• Linalool and 1,8-cineole were the most effective individual terpenes tested.
• Linalool and 1,8-cineole are the main active constituents in Lavandula latifolia oil.

Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is an important new invasive pest of stone and berry fruits in North America and current control methods require frequent application of synthetic pesticides. This has created a need for new and environmentally friendly biopesticides for the control of SWD. This paper investigated the potential of nine essential oils from avocado (Persea americana Mill.), neem (Azadirachta indica A. Juss), kukui nut (Aleurites moluccana L.), macadamia nut (Macadamia integrifolia Maiden & Betche), spike lavender (Lavandula latifolia Vill.), Grosso lavandin leaf and flower (Lavandula × intermedia cv ‘Grosso’), and Provence lavandin leaf and flower (Lavandula × intermedia cv ‘Provence’) as well as three major monoterpene constituents of lavender essential oils: 1,8-cineole, 3-carene and linalool for their ability to control SWD through fumigation and contact toxicity assays as well as oviposition deterrent activity. Linalool was found to be the most effective monoterpene in fumigation assays (EC50 1.85 μL/L air) and spike lavender floral essential oil was found to be the most effective whole oil (EC50 3.79 μL oil/L air). In contact toxicity assays 1,8-cineole (EC50 0.67%) was the most effective monoterpene while avocado (EC50 0.54%) and spike lavender (EC50 0.69%) oils were the most effective whole oils. No significant oviposition deterrent activity was observed. This report indicates that L. latifolia essential oil and commercially available avocado oil are strong lead candidates for management of SWD. Furthermore the activity of L. latifolia essential oil is likely due to the high content of 1,8-cineole and linalool. This is the first report of significant insecticidal activity by these oils and compounds against SWD.