Xylella fastidiosa and the olive quick decline syndrome in Southern Italy

Abstract EN

The olive quick decline syndrome (OQDS) is a devastating disease that occurs in the Salento peninsula of Apulia (south-east Italy).

In autumn 2103 the xylem-limited Gram-negative bacterium Xylella fastidiosa was detected by laboratory assays in symptomatic plants, and studies for determining its epidemiology and involvement in the OQDS genesis were intiated.

The bacterium was found in all diseased olive trees sampled in different and geographically separated infection foci, and culturing of over 50 isolates, each from a distinct OQDS focus, was accomplished.

A representative bacterial isolate from a pure culture, identified by multilocus sequence typing (MLST) as belonging to sequence type 53 (ST53) of X.

fastidiosa subsp.

pauca, was used for needle-inoculation of pot-grown olive and other hosts, reproducing the field symptomatology.

The spittlebug Philaenus spumarious was experimentally proven to be the vector of the olive-infecting bacterial strain.

There is no cure for Xylella infections and effective methods for inoculum reduction in the field are few.

Thus, combating X.

fastidiosa-induced diseases relies primarily on the identification and use of resistant germplasm, as well as surveillance for restraining disease spreading through extensive field monitoring, uprooting infected and neighbouring healthy plants in newly detected foci, and vector control.

The latter is being attempted in Apulia through mechanical weeding in late winter-early spring to kill juveniles that thrive on weeds, followed by chemical treatments of olive trees in late spring-early summer to control the adults.