Influence of Citrus Plants Infected withXylella fastidiosaon Stylet Penetration Activities ofBucephalogonia xanthophis(Hemiptera: Cicadellidae)

Abstract

AbstractXylem colonization by Xylello fastidiosa promotes physiological, biochemical, and morphological alterations in citrus plants causing citrus variegated chlorosis (CVC) disease, which might influence the feeding behavior of vectors of this bacterial pathogen and its spread in citrus groves. By using the electrical penetration graph technique, we compared the numbers and durations of stylet penetration activities by adults of the sharpshooter vector Bucephalogonia xanthophis (Berg) (Hemiptera: Cicadellidae) on healthy and X. fastidiosa-infected sweet orange seedlings (Citrus sinensis (L.) Osbeck, cv. Pera). Infected plants were either symptomatic, exhibiting the typical CVC, symptoms or totally asymptomatic. The mean time needed to contact xylem and start xylem sap ingestion after the onset of the first probe was similar among treatments. However, the average time elapsed between the onset of the first probe and the beginning of sustained xylem ingestion (>5 min) was longer on plants with CVC symptoms than on infected asymptomatic or healthy plants. In addition, the length of time spent in ingestion activities was much shorter on symptomatic plants. Our results showed that CVC symptomatic citrus plants were a less acceptable host than uninfected or asymptomatic X. fastidiosa-infected plants. Furthermore, our results support the hypothesis that symptomless infected citrus trees may be more important as sources for CVC spread than severely diseased ones.