Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2017
Publication Date: 10/1/2017
Citation: Cervantes, F.A., Backus, E.A. 2017. EPG waveforms of blue green sharpshooter: impedance and voltage level effects on stylet probing. Presented at Entomological Society of America Annual Meeting, Nov 5-8, 2017, Denver, CO.
Technical Abstract: Blue-green sharpshooter (BGSS), Graphocephala atropunctata, is a native California vector of Xylella fastidiosa (Xf) a foregut-borne bacterium that is the causal agent of Pierce’s disease in grapevines. A 3rd-generation, AC-DC electropenetrograph (EPG) was used to record probing behaviors of adult BGSS on healthy grapevines. This talk presents a waveform library for BGSS EPG waveforms as well as effects of different EPG monitor settings on performance of probing behaviors. AC applied signal was used with impedance of 10^7 or 10^9 Ohms at 50 or 200 mV. Waveforms presented are nearly identical to those of the glassy-winged sharpshooter, Homalodisca vitripennis, previously published. Thus, BGSS also produces an X-wave that is complex in structure and components. Previous evidence supports that the X wave represents the inoculation behavior of Xf, a combination of egestion and salivation. Numbers of X-waves were significantly higher at 10^9 Ohms, while durations were longer at 200 mV. X-wave components C1 (discharging egestion) and B1s (tasting and rinsing egestion) were longer at 200 mV, while B1w (representing salivation) was shorter at 10^9 Ohms. Results from this study will help determine monitor settings for future EPG studies of inoculation behaviors on Xf-resistant and -susceptible grapevine. The ultimate goal is to aid in development of grapevines resistant to Xf inoculation by the vector.