|Yokomi, Raymond - Ray|
|De Stradis, Angelo|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2014
Publication Date: 8/1/2014
Citation: Saponari, M., Loconsole, G., Cornara, D., Yokomi, R.K., De Stradis, A., Boscia, D., Bosco, D., Martelli, G., Krugner, R., Porcelli, F. 2014. Infectivity and transmission of Xylella fastidiosa Salento strain by Philaenus spumarius L. (Hemiptera: Aphrophoridae) in Apulia, Italy. Journal of Economic Entomology. 107(4):1316-1319. Interpretive Summary: In October 2010, olive trees with wilt symptoms of unknown etiology were observed dying in the Salento Peninsula (Southern Italy) with a condition described as “Olive quick decline syndrome"(OQDS). By 2013, the affected area had grown to ~10,000 ha. In September 2013, OQDS symptomatic olive trees were found to be positive for Xylella fastidiosa, a quarantined pathogen in the European Union. This finding prompted an immediate search for potential insect vectors of this xylem-limited bacterium. During an intensive 3-month survey in the infected area, the most common xylem-feeding insect collected was the meadow spittlebug, Philaenus spumarius. Sixty seven percent of individual spittlebugs (40/60) were found positive for the pathogen by PCR assay. Transmission tests of field-collected spittlebugs resulted in 2 of 5 periwinkle test plants becoming infected, however, zero of seven olive test plants became infected. Sequence of PCR products from infected periwinkle test plants was identical to X. fastidiosa from infected field trees. Although transmission to olive was not demonstrated, the ability of P. spumarius to transmit X. fastidiosa to recipient plants proves that this bacterial strain can be spread by an indigenous vector in Italy. These results are critical to establish appropriate methods to limit spread of this quarantined pathogen.
Technical Abstract: Discovery of X. fastidiosa from olive trees with “Olive quick decline syndrome" (OQDS) in October 2013 on the western coast of the Salento Peninsula prompted an immediate search for insect vectors of the bacterium. The dominant xylem-fluid feeding hemipteran collected in olive orchards was the meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Cercopidae) during a three-month survey. Adult P. spumarius collected from ground vegetation in X. fastidiosa-infected olives orchards were 67% (40 out of 60) positive for X. fastidiosa in November 2013 by PCR assays. Transmission tests with P. spumarius collected from the Salento area were conducted. After a 96-h inoculation access period with eight to 10 insects per plant and a 30-d incubation period, PCR results showed P. spumarius transmitted X. fastidiosa to two of five periwinkle plants but not to seven olive plants. Sequences of PCR products from infected periwinkle were identical to X. fastidiosa from field trees. These data identified P. spumarius as a vector of X. fastidiosa infecting olives trees in the Salento Pennisula, Italy. Research findings are critical for designing pathogen and vector survey methods, as well as management and/or eradication measures to limit spread of the pathogen to non-infected areas.