Feeding and survival of citrus sharpshooters (Hemiptera : Cicadellidae) on host plants
The liquid excretion and survival of the sharpshooters Dilobopterus costalimai Young and Oncometopia facialis (Signoret), vectors of Xylella fastidiosa in citrus, were measured on various host plants as an indirect approach to assess their feeding and performance on these hosts and determine suitable plants for laboratory rearing. Adult females of D. costalimai showed the highest excretion rate on Vernonia condensata (Asteraceae). O. facialis excreted larger volumes on three species of Vernonia and on Lantana camara (Verbenaceae). On average, single D. costalimai females excreted a liquid volume equivalent to 292 times its body volume per day when feeding on V condensata, whereas O. facialis females excreted 430 times their body volume on the same host. In contrast, the excretion rates of D. costalimai and O. facialis females on Citrus sinensis did not exceed 248 and 140 times their body volume per day, respectively. The mortality of adults after 96 h was lower on hosts upon which higher liquid volumes were excreted; therefore, there is a positive relationship between the excretion rate by the sharpshooters and their nutritional adequacy to hosts. V condensata is a suitable host to maintain adult populations of both sharpshooters in the laboratory.