Chemical ecology of the Asian citrus psyllid, Diaphorina citri (Kuwayama) and its parasitoid, Tamarixia radiata Waterston (Hymenoptera: Eulophidae)

Parasitoids use volatile chemicals emanating from their conspecifics and from their host or host habitat for foraging, host location and host recognition. Tamarixia radiata is an ectoparasitoid of several psyllid species including the Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama), which vectors the bacteria Liberobater asiaticum known to be responsible for the highly devastating citrus greening disease. Despite T. radiata’s role as an important biocontrol agent of ACP, information on the roles of chemical cues in mate and host location behaviors of this parasitoid and its ACP host is completely lacking. Using standard solvent extraction and solid phase microextraction (SPME) techniques, volatiles were trapped from adult male and female D. citri and its parasitoid, T. radiata under ambient laboratory conditions. Collected volatiles were analyzed using gas chromatography coupled with mass spectrometer (GC-MS). The putative pheromones of male and female T. radiata as well as the ACP were identified. The pheromones of each sex of T. radiata differ and are shared with certain components of the pheromone blend of their psyllid host. These results suggest that female T. radiata exploit certain pheromone components of its ACP host as kairomones for host finding. Further study to determine the roles of the identified pheromones in the behavioral ecology of T. radiata and ACP is onging. This study should enhance our understanding of mate and host finding by this parasitoid and its host and improve future management strategies of this important pest.