We examined the substrate-borne vibrational signals used in communication between the sexes in Diaphorina citri Kuwayama (Hemiptera: Psyllidae), a vector of huanglongbing (an economically devastating disease of citrus), in an anechoic chamber and an olfactometer. Males and females both primarily produced simple, low-amplitude vibrational signals at multiples of 170-250 Hz, ranging in duration from 140 to 700 ms. The vibrational frequencies of males and females were negatively correlated with mass, but the correlation was statistically significant only for males. Females replied to male calls within an interval of 0.3-1.2 s. Such signals are within the ranges of signals observed for other psyllids. Female-female interactions were occasionally observed. Intervals between male calls were not significantly different whether or not females replied. In an olfactometer, calling rate did not differ between virgin males exposed to odors from virgin females on citrus versus those exposed only to clean air. However, the latent period for initialization of calling was significantly shorter for males exposed to clean air, suggesting that in the absence of olfactory cues psyllids might be more inclined to use acoustic signals to communicate with conspecifics. Moreover, calling rate and latency to initialization of calling were positively and negatively correlated, respectively, with male age, suggesting that males are more likely to call the longer they remain unmated.