ABSTRACT Siamese orange (Citrus nobilis Lour) is a horticultural plant having the main pest, the fruit fly Bactrocera sp. The solution is eviromentally friendly control is the use of trap combined with the attractant of lemongrass (Cymbopogon nardus L.). The purpose of this study is to get the dosage of lemongrass oil which is ablest to trap most fruit fly on citrus plants. This research was c…