Abstract: ObjectiveThe selective behavior of Encarsia guadeloupae Viggiani on different host plants of Alerodicus dispersus Russell was revealed to provide theoretical references for finding the best host plant for the parasitoid breeding.MethodThe selective differences of E. guadeloupae to A. dispersus on six kinds of host plants (guava, poinsettia, cas-sava, papaya, tomato, capsicum) were determined using randomly put host plants (free selection) and “Y” type olfac-tometer tests (directional selection). ResultThe parasitic ratios of E. guadeloupae on A. dispersus from different kinds of host plant were listed from high to low as follows: guava> poinsettia> capsicum> papaya> cassava> tomato. The “Y” type olfactometer tests of volatiles from different host plants indicated that E. guadeloupae had the highest taxis to poinsettia and second highest taxis to guava, and tomato and cassava had weak attractiveness to E. guadeloupae. ConclusionBoth poin-settia and guava have higher attractiveness to E. guadeloupae than other plants, which can be considered as the suitable host plants for breeding E. guadeloupae.