Electrophysiological response of Pentastiridius leporinus (Hemiptera: Cixiidae) to plant volatiles and the ultrastructure of its antennal sensilla

The planthopper Pentastiridius leporinus transmits the phytoplasma 'Candidatus Phytoplasma solani' and the bacterium 'Candidatus Arsenophonus phytopathogenicus' to various agricultural crops and vegetables, mainly in Germany and neighbouring countries. We collected headspace volatiles from the wild potato species Solanum bulbocastanum and tested antennal responses of P. leporinus using gas-chromatography-electroantennographic detection (GC-EAD). Two identified compounds, nonanal and decanal, were then tested on female antennae using electroantennography (EAG). Both compounds elicited significant dose-dependent EAG responses. Scanning electron microscopy revealed three sensillum types on the pedicel (chaetica, campaniform-like, plate-organs) of both female and male specimens. Transmission electron microscopy showed two coeloconic sensilla inside the Bourgoin organ in ultrathin antennal sections of a female. This is the first report of electrophysiologically active plant volatiles and antennal ultrastructure for this vector.