Acoustic signals function as a critical prereproductive isolation factor among singing insects and can serve as a valuable tool in insect systematics. Acoustic recognition of psylloids is crucial in establishing duets. However, research focused on acoustic divergence and specific recognition of closely related psylloid species is scarce. Moreover, active adult psylloids may exhibit acoustic behavior on nonhost plants in natural conditions even though the majority of species is highly host specific. Acoustic signals transmitted among different host plants with various structural properties may be affected and thereafter influence the mating behavior of psylloids. We studied the acoustic behavior of two sympatric and closely related species of Trioza Foerster (Triozidae), each of whose host plant is a different species of Neolitsea (Benth. & Hook.) Merr. (Lauraceae), to examine their acoustic recognition and the host versus nonhost plant effects on acoustic signals and behavior. We found that the chirp duration varied significantly between the two selected species of Trioza. These two species exhibited features of prereproductive isolation through acoustic recognition, as demonstrated by infrequent duets and mating between interspecific pairs. Both species of Trioza, especially males, exhibited a shorter chirp duration on nonhost plants compared with the chirp duration on host plants. However, the dominant frequency of the two species of Trioza was less influenced by plant effects. Lastly, acoustic characteristics along with morphological and biological characteristics provided clear evidence that one of the two species of Trioza is novel. A description of this new species is provided.