Technical Abstract: Plant essential oils have a number of roles in insect pest management. For male Ceratitis capitata, these roles include male-targeted attractants for traps and aromatherapy exposure for increased mating success. Essential oils that affect C. capitata behavior may be from either host or non-host plants, and biological basis for these effects is unknown. As part of research to identify volatile chemicals responsible for these effects, laboratory behavioral tests were conducted in Florida with sterile males. Essential oils tested including angelica oil, cubeb oil, ginger root oil, manuka oil, orange oil and tea tree oil. Related substances tested were trimedlure and a-copaene. The role of substrate concentration on short-range attraction, as well as substrate toxicity will be presented.