The Use of Plant Extract for Attractant of Predators and Parasitoids of Cotton LeafhopperCotton production is restricted by pest attack. The key pest of cotton is cotton leafhopper, Amrasca biguttula. Aerial spray to control of this pest caused the increase of bollworm population. Therefore, the use of parasitoids and predators could be a proper method to control the leafhoppers. The use of attractant to in-crease predator and parasitoid population on cotton field would also increase the role of those natural enemies as an effective biotic mortality factor. Plant extracts, especially in the form of essential oils, have been used as attractants for the natural enemies; however attractant for natural enemies of cotton leafhopper has not been intensively developed. Therefore, this research aims were to evaluate some plant extracts that may function as an attractant for egg parasitoid and predators of cotton leafhopper in laboratory tests using olfactometry method, and also to test the effectiveness of the attractant in increasing population of parasi-toids and predators in cotton fields. The plant extracts were of leafhopper-infested-cotton leaves, maize stalks and leaves, and Melalaeuca brachteata leaves, using organic solvents. Results showed that the essential oils of leafhopper-infested-cotton leaves and black-tea tree leaves could be used as an attractant for the hopper egg parasitoids. The parasitoids showed positive response to the essential oils of leafhopper-infested-cotton leaves and black-tea tree leaves in olfactometry tests. The use of those attractants in cotton fields increased parasitoid population by 179% compared to the control. Essential oils of the tested pants did not have any effect on predators, such as ladybird beetles, staphylinid beetles, mirid bugs, as well as lacewings.