Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 29, 2005
Publication Date: March 1, 2006
Citation: Joost, P.H., Backus, E.A., Yan, F. 2006. Correlation of stylet activities by the glassy-winged sharpshooter, Homalodisca coagulata (Say), with electrical penetration graph (EPG) waveforms. Journal of Insect Physiology. 52(3):327-337 Interpretive Summary: Glassy-winged sharpshooer (GWSS), Homalodisca coagulata (Say), is an efficient vector of Xylella fastidiosa (Xf), the causal bacterium of Pierce’s disease, and leaf scorch in almond and oleander. Acquisition and inoculation of Xf occur sometime during the process of stylet penetration into the plant. That process is most rigorously studied via electrical penetration graph (EPG) monitoring of insect feeding. This study provides part of the crucial biological meanings that define the waveforms of each new insect species recorded by EPG. By synchronizing AC EPG waveforms with high-magnification video of GWSS stylet penetration in artifical diet, we correlated GWSS stylet activities with three previously described EPG pathway waveforms, A1, B1 and B2, as well as one ingestion waveform, C. This detailed understanding of stylet penetration behaviors of GWSS is an important step toward identifying the instant of bacterial inoculation which, in turn, will be applied to studies of disease epidemiology and development of host plant resistance.