Etude de la prévalence des vecteurs potentiels naturellement infectés par Xylella fastidiosa subsp. Pauca dans les oliveraies du sud de l'Italie

Abstract

In 2013, the bacterium Xylella fastidiosa was detected for the first time in Europe in the Italian region of Puglia. This bacterial pathogen decimates the olive trees of the Salento peninsula with important economic consequences. The bacterium is transmitted by insects of the suborder Auchenorrhyncha feeding on xylem sap. The only European vector insect identified so far is Philaenus spumarius. The eradication measures of X.fastidiosa ordered by the European Commission do not seem to stop the spread of the bacterium in southern Italy. There are few studies on the potential European vectors of X.fastidiosa and knowledge about the vector P.spumarius in Europe is in its early stages. In order to understand the links between the bacterium and a new invasive model insect in Europe, a preliminary acquisition test on artificial diets was carried out on Halyomoprha halys in the GxABT laboratory. At this stage, the preliminary test did not understand the interactions between these two organisms. In order to enrich knowledge, studies on the prevalence of P.spumarius and the population dynamics of P.spumarius, N.campestris and other Auchenorrhyncha, whose potential vectors of X.fastidiosa, were carried out in two olive groves in the surroundings of Lecce within the framework of the Italian project "Ge.S.Oliv.". Despite the heterogeneity of the two olive groves, the current knowledge on Auchenorrhyncha dynamics in Salento olive groves in the spring seems to be confirmed by this study. However, the insect population studied appears to decrease in trees severely pruned in contrast to unpruned trees and increase in a grassland used as refuge after tillage of the plot. These observations could require thorough research in order to develop a push-pull strategy with cultural control of the vector. Moreover, the prevalence of P.spumarius infected by the bacterium in the studied olive groves is lower than that observed near the epicenter of the epidemic in the surroundings of Gallipoli. In order to feed knowledge of the potential vectors of X.fastidiosa, it would be interesting to taxonomically identify the Auchenorrhyncha species caught on the infected olive trees as well as to detect the presence of the bacterium in these and to be able to test their possible transmitting capacity.