FEEDING SITES AND FOOD INTAKE OF Bucephalogonia xanthophis (BERG) (HEMIPTERA: CICADELLIDAE), A SHARPSHOOTER VECTOR OF Xylella fastidiosa, ON CITRUS PLANTS
The sharpshooter Bucephalogonia xanthophis (Berg) (Hemiptera: Cicadellidae) is an important vector of Xylella fastidiosa. a bacterium that causes citrus variegated chlorosis. This study aimed to identify the preferred feeding sites and periods Of this vector on citrus, in order to improve Our understanding of the feeding behavior related to the transmission of this pathogen. The feeding sites were determined in a choice experiment, in which 30 adults were released inside observation chambers (n = 10) containing a sweet orange seedling [Citrus sinensis (L.) Osbeck]. One, fifteen, twenty-one, twenty-five, thirty-nine, forty-five, and forty-nine hours after the release. the number of insects on the upper (stem with sprouts) and bottom (primary stern, Lip to 40 cm above soil) parts of the plant was recorded. To determine the feeding periods, 20 males and 20 females of B. xanthophis were individually confined on the sterns of sweet orange seedlings, and the honeydew excretion (indirect measure of ingestion) was quantified for 48 hours, during periods of day and night. Most B. xanthophis individuals (91 %) were observed on the upper part of the plant, mainly on the stems of the young shoots (62%). A larger Volume of excretion and higher proportion of excreting individuals were observed during the photophase for both males and females, indicating that daytime is the preferred feeding period for this vector. Therefore, in transmission studies of X. fastidiosa one should consider the preference of B. xanthophis for stems of young shoots and its higher feeding activity during the photophase.