The efficiency of Xylella fastidiosa transmission by sharpshooters on citrus plants is low and varies with the vector species. The feeding behavior of the sharpshooter vector related to X. fastidiosa acquisition and inoculation is one of the probable conditioning factors in transmission efficiency. The objective of this study was to assess the behavior of two sharpshooter species, Dilobopterus costalimai Young and Oncometopia facialis (Signoret), in selection of citrus nursery trees and feeding places and to ascertain the influence of sprouting on plant attractiveness to the vectors. Free choice tests were performed with the two species in observation chambers (63 x 63 x 120 cm), releasing 40 individuals per chamber. The number of dead insects were assessed as well as those that chose, or not, one of the treatments, at 3, 15, 21, 24, 39, 45 and 48h after the release. For D. costalimai the leaves were important at the start of host selection, and were substituted over time by the secondary branch. D. costalimai preferred to stay on the secondary leaf nervures followed by the secondary branch. O. facialis showed no difference in preference for staying on the leaves (central and secondary nervures) and secondary branch on citrus plants, and this varied with the time of day. The presence of sprouting in the nursery trees increased the attractiveness of the plant to the two sharpshooter species raising the chances of X. fastidiosa acquisition or inoculation. So, control measures should be adopted against these insects in periods of greater vegetation in orange orchards.
Citrus sinensis; citrus variegated chlorosis; sharpshooter vector; host selection
