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 significantlydeterred bythe essential oils of marjoram (Origanum majorana L.), lavender (Lavandula angustifolia L.) and mint (Mentha arvensis L.) at several concentrations, and bythe oil of rosemary (Rosmarinus officinalis L.) at 1% concentration