Labiate essential oils affecting host selection and acceptance of Thrips tabaci lindeman

Essential oils from plants within the Lamiaceae family at several concentrations were evaluated for their repellent and deterrent properties against Thrips tabaci Lindeman (Thysanoptera: Thripidae), the onion thrips. Rosemary (Rosmarinus officinalis L.) essential oil repelled onion thrips females at 10% concentration in olfactometer bioassays. In leaf disc bioassays on leek (Allium porrum L.), 1% concentration of rosemary oil inhibited settling within a 4-h period. In dual-choice experiments marjoram (Origanum majorana L.) and mint (Mentha arvensis L.) oil both at 0.1% and 1% concentrations significantly deterred the egg-laying activity of thrips females on treated leaf discs. Lavender (Lavandifla angustifolia L.) oil at 1% and sage (Salvia officinalis L.) oil at 0.1% concentration affected oviposition. In no-choice assays, thrips oviposition rate was significantly reduced by about 45-60% compared to the untreated control after application of marjoram and lavender oil at 1% or 0.1% concentration. With mint oil, oviposition deterrence was found only at 1% concentration. Repellent and/or deterrent essential oils combined with other control measures against T tabaci may contribute to the enhancement of biological or integrated pest management strategies. (C) 2003 Elsevier Science Ltd. All rights reserved.