Vetiver grass(Vetiveria zizanioides L.)was previously found to effectively attract female adults of Chilo suppressalis(Walker),an important pest of rice.To determine the volatile compounds involved in this attraction,electroantennography(EAG)responses to seven synthetic volatiles released from vetiver plants were examined.Our results indicated that the responses of C.suppressalis adult antennae to the different compounds varied widely.The compounds elicited strong EAG responses in female antennae were subsequently selected for further EAG response tests,namely,caryophyllene,β-ocimene,linalool andα-pinene.EAG responses to a combination of these four compounds did not differ significantly from the individual compounds.However,pair combination tests indicated that 0.01μgμL~(–1) linalool and 50μgμL~(–1)α-pinene,50μgμL~(–1) caryophyllene and 0.01μgμL~(–1) linalool,0.01μgμL~(–1)β-ocimene and 0.01μgμL~(–1) linalool,and 0.01μgμL~(–1)β-ocimene and 50μgμL~(–1) caryophyllene elicited significantly greater EAG responses in 3-day female moths compared to the 1-day female.These compound combinations and the corresponding ratios are probably playing an important role in attracting female adults of C.suppressalis to the vetiver grass. Vetiver grass (Vetiveria zizanioides L.) was previously found to be effective attract female adults of Chilo suppressalis (Walker), an important pest of rice. To determine the volatile compounds involved in this attraction, electroantennography (EAG) responses to seven synthetic volatiles released from vetiver plants were examined. Our results indicate that the responses of C.suppressalis adult antennae to the different compounds varied widely. These compounds elicited strong EAG responses in female antennae were selected for further EAG response tests, namely, caryophyllene, β-ocimene, linalool and [alpha] -pinene. EAG responses to a combination of not differ significantly from the individual compounds. If the combination of these four compounds did not differ significantly from the individual compounds, (-1) cinalophyllene and 0.01μgμL ~ (-1) linalool, 0.01μgμL -1 β-ocimene and 0.01μgμL -1inalool, and 0.01μgμL -1 β-ocimene and 50μgμL ~ (-1 ) caryophyllene elicited significantly greater EAG responses in 3-day female moths compared to the 1-day female. These compound combinations and the corresponding ratios are likely playing an important role in attracting female adults of C.suppressalis to the vetiver grass.