For three consecutive years, surveys were conducted in 24 olive orchards located in the demarcated Xylella-infected area of Apulia (southern Italy), with the aim of identifying xylem-feeder species serving as vector of Xylella fastidiosa in olives. Surveys were carried out periodically from spring to late autumn and insects were collected by sweeping net using constant sampling units from olive canopies, ground vegetation and border plants when present. All insects were subjected to qPCR for the detection of X. fastidiosa (individually or in groups of 5), as well as to the morphological identification. Besides the two spittlebug vectors (Philaenus spumarius and Neophilaenus campestris), more than 3,000 specimens belonging to 37 different species (27 Cicadomorpha and 10 Fulgoromorpha) of 34 genera and 10 families were collected. The detection of the bacterium in spittlebugs, xylem-feeders and on some of the most abundant phloem-limited species, showed that: (i) for the two known vectors occurring in the area, a higher incidence of positive specimens was detected for P. spumarius (up to 50%) with the occurrence of Xylella-positive insects for a prolonged period, compared with N. campestris (10% of positive specimens, detected to a limited extent in late spring), and (ii) for both species the incidence of positive specimens was consistently higher when they were collected from olive canopies compared with ground vegetation or border plants; (iii) amongst the xylem-feeders, none of the specimens collected and tested for Cicada orni, Cercopis sanguinolenta and Lepyronia coleoptrata were found positive; (iv) conversely, few positive specimens were recovered for the following leafhoppers and planthoppers: Thamnotettix zelleri (8.33% in olives and 3.7% in weeds); Latilica tunetana (1.77% in olives, 2.2% in weeds) and for Euscellis lineolatus (none in olives, 0.06% in weeds). Regarding the possible role as vector of X. fastidiosa for these planthopper/leafhopper species, transmission tests have already excluded the capability of the L. tunetana to retain and transmit the bacterium, whereas experimental tests are ongoing for T. zelleri.
Surveys for vectors and candidate vectors of Xylella fastidiosa in olive orchards in Apulia
Cavalieri V;
2019
Abstract
For three consecutive years, surveys were conducted in 24 olive orchards located in the demarcated Xylella-infected area of Apulia (southern Italy), with the aim of identifying xylem-feeder species serving as vector of Xylella fastidiosa in olives. Surveys were carried out periodically from spring to late autumn and insects were collected by sweeping net using constant sampling units from olive canopies, ground vegetation and border plants when present. All insects were subjected to qPCR for the detection of X. fastidiosa (individually or in groups of 5), as well as to the morphological identification. Besides the two spittlebug vectors (Philaenus spumarius and Neophilaenus campestris), more than 3,000 specimens belonging to 37 different species (27 Cicadomorpha and 10 Fulgoromorpha) of 34 genera and 10 families were collected. The detection of the bacterium in spittlebugs, xylem-feeders and on some of the most abundant phloem-limited species, showed that: (i) for the two known vectors occurring in the area, a higher incidence of positive specimens was detected for P. spumarius (up to 50%) with the occurrence of Xylella-positive insects for a prolonged period, compared with N. campestris (10% of positive specimens, detected to a limited extent in late spring), and (ii) for both species the incidence of positive specimens was consistently higher when they were collected from olive canopies compared with ground vegetation or border plants; (iii) amongst the xylem-feeders, none of the specimens collected and tested for Cicada orni, Cercopis sanguinolenta and Lepyronia coleoptrata were found positive; (iv) conversely, few positive specimens were recovered for the following leafhoppers and planthoppers: Thamnotettix zelleri (8.33% in olives and 3.7% in weeds); Latilica tunetana (1.77% in olives, 2.2% in weeds) and for Euscellis lineolatus (none in olives, 0.06% in weeds). Regarding the possible role as vector of X. fastidiosa for these planthopper/leafhopper species, transmission tests have already excluded the capability of the L. tunetana to retain and transmit the bacterium, whereas experimental tests are ongoing for T. zelleri.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
