The percentage of feeding damage area on leek (Allium porrum L.) leaf discs and the adult survival was assessed after 24 h. Onion thrips were significantly deterred by the essential oils of marjoram (Origanum majorana L.), lavender (Lavandula angustifolia L.) and mint (Mentha arvensis L.) at several concentrations, and by the oil of rosemary (Rosmarinus officinalis L.) at 1% concentration