Video and AC EPG waveform correlations of Homalodisca coagulata stylet activity during probing
P. Houston Joost, firstname.lastname@example.org, USDA-ARS, EIDP, 9611 Riverbend Ave, Parlier, CA and Elaine Backus, email@example.com, USDA-ARS PWA, San Joaquin Valley Agric. Sci. Ctr., Exotic & Invasive Diseases & Pests Research, 9611 So. Riverbend Ave, Parlier, CA.
Glassy winged sharpshooter (GWSS), Homalodisca coagulate (Say), is the main vector of Xylella fastidiosa in grapevine. A detailed understanding of GWSS probing behavior is important because X. fastidiosa is acquired and transmitted when GWSS probes. To further eluicidate GWSS probing behavior we used AC electrical penetration graph technique (AC EPG) and video to corelate GWSS probing behaviors to EPG waveform patterns in artifical diets. Three previously described waveforms, A1, B1 and B2, were correlated with GWSS stylet activity. Fasicle protraction, alternating mandible retraction and maxillae fluttering were correlated to specific parts of the A1 waveform. Salvia sheath formation was also observed in A1. Waveform B1 was correalated to maxillae fluttering within the salvary sheath. Termination of the B1 waveform and maxillae fluttering occurred once the stylets exited the salviary sheath. Waveform B2 was assocaited with stylet path branching within the salviary sheath. During B2, GWSS would “saw” a new stylet branch in the salvairy sheath by rapidly retracting and protacting its stylet fascicle in an askewed direction from the original branch. Termination of B2 occurred when the stylets “sawed” through the salvariy sheath.