Abstract:The location and preference of adult Asian citrus psyllid, Diaphorina citri Kuwayama, a vector of the citrus huanglongbing (greening disease) Liberobacter asiaticum, on two host plants, Murraya exotica L. and Citrus depressa Hayata, were investigated in Okinawa Prefecture, Japan. While the adults of D. citri were found on all parts of the C. depressa tree and on the M. exotica tree, all of the D. citri eggs and most of the nymphs and adults were found on young shoots and young leaves. We suggest that it is possible to save labor in the investigation and control of the psyllid by attentively checking the young shoots of M. exotica. Investigation on the distribution of D. citri adults on M. exotica plantlets hung upside down in a container showed that although no difference was found between frequencies of males on young leaves and mature leaves, significantly more females were found on the apical buds, suggesting that females have a preference for this part of the tree.