Abstract: In this study, behavioral responses of Hyalesthes obsoletus to six syntheticmixtures and nine single compounds, previously identified from the headspace of Vitexagnus-castus (chaste tree) and Urtica dioica (nettle), were investigated in Y-tube olfactometerbioassays. Choice tests revealed differences in the behavioral responses of males and femalesto the volatiles that they were exposed to. Results showed that males were attracted to a fivecompounds mixture containing volatiles identified from chaste tree. Females were attracted toa six compounds mixture of chaste tree volatiles, and to a five compounds mixture of volatilesidentified from nettle. Neither males nor females showed attractivity or repellency toward thesingly tested compounds.