Quantitative comparison of stylet penetration behaviors of glassy-winged sharpshooter on selected hosts
New Zealand is threatened by invasion of the glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), an important vector of Xylella fastidiosa, it gram-negative bacterium that causes Pierce's disease ill grape (Vitis spp,) and scorch diseases ill many other horticultural crops. Therefore, all understanding of the host acceptability, feeding behavior, and potential vector efficiency of glassy-winged sharpshooter oil New Zealand crops is important. We tested]lost plant acceptance and feeding behaviors of glassy-winged sharpshooter oil three common horticultural crops, grown in New Zealand (apple [Malus spp. ] grape, and citrus [Citrus SPI]), and a native plant (Metrosideros excelsa [ =tomentosa ] Richard, pohutukawa). using the electrical penetration graph (EPG) technique. Probing (stylet penetration) behaviors varied among the host plants, primarily due to differences in waveform eveut durations. Apple and grape were the most accepted host plants. oil which glassy-winged Sharpshooter spent the majority of its time oil the plant probing and readily located and accepted a xylem cell for ingestion. This resulted in long durations of sustained xylem fluid ingestion. In contrast, pohutukawa was the least accepted host. Oil this plant, glassy-winged sharpshooter spent less time probing and engaged in longer and more frequent testing/searching and xylem-testing activities, rejected xylem cells frequently, and spent less time with stylets resting, before accepting a xylem cell all ultimately performing the same amount Of sustained ingestion. Citrus plants contaminated with sublethal insecticide residues were intermediate between these extremes, with some acceptance of xylem, but less ingestion, probably (due to presumed partial paralysis of the cibarial muscles. Implications' of the results in terms of host plant acceptance and file development of a stylet penetration index are discussed.