Ascogaster quadridentata (AQ) is an important parasitoid ofthe codling moth (CM), Cydia pomonella, the key pest of apples worldwide.Use of the AQ sex pheromone could assist apple growers in estimating AQnumbers in target orchards, indicating whether existing parasitoid populationsare sufficient to keep CM below economic. Also, identification and deploymentof kairomones mediating host location could augment AQ management in targetorchards, increasing immigration while decreasing emigration of the parasitoid.Female AQ-produced volatiles captured on Porapak Q and bioassayed in Y-tubeolfactometers attracted male but not female AQ. GC-EAD analysis of thePorapak Q volatile extract revealed 3 compounds that elicit responses bymale AQ antennae. GC-MS indicated, and assays of standards confirmed, thatthese compounds were Z9,Z12-octadecadienal, Z9-hexadecadienal and 3,7,11-trimethyl6,10 dodecadienal. In olfactometer bioassays Z9,Z12-octadecadienalsingly was highly attractive to male AQ. Host location by AQ is mediatedby kairomones released from the CM host. Porapak Q-captured volatilesfrom CM wing scales and CM eggs, as well as CM sex pheromone componentswere tested for their attractiveness to both male and female AQ, and identificationof kairomones is underway.