Phenolic Extract from Olive Leaves as a Promising Endotherapeutic Treatment against Xylella fastidiosa in Naturally Infected Olea europaea (var. europaea) Trees.

(1) Background: Since 2013, the pathogenic bacterium Xylella fastidiosa has been severely affecting olive production in Apulia, Italy, with consequences for the economy, local culture, landscape and biodiversity. The production of a phenolic extract from fresh olive leaves was employed for endotherapeutic injection into naturally infected olive trees by Xylella fastidiosa in Apulia region, Italy. (2) Methods: The effectiveness of the extract was tested in vitro and in planta in comparison with analogous treatments based on garlic powder and potassium phosphite. (3) Results: The uptake of phenolic compounds from olive leaves through a trunk injection system device resulted in a statistically significant increase in leaf area index and leaf area density, as well as in the growth of newly formed healthy shoots. Plant growth-promoting effects were also observed for potassium phosphite. Moreover, the bacteriostatic activities of the phenolic extract and of the garlic-powder-based solution have been demonstrated in in vitro tests. (4) Conclusions: The results obtained and the contained costs of extraction make the endotherapeutic treatment with phenolic compounds a promising strategy for controlling X fastidiosa to be tested on a larger scale, although the experiments conducted in this study proved not to be suitable for centenary trees.

Testing the Single and Combined Effect of Kaolin and Spinosad against Bactrocera oleae and Its Natural Antagonist Insects in an Organic Olive Grove.

The presence and infestation level of Bactrocera oleae was monitored in an organic olive orchard divided into differently treated parcels with kaolin (K), spinosad (S) and with kaolin and spinosad (K + S) in alternate rows. The treatments did not seem to affect olive fruit fly population dynamics, while statistically significant protective effects were recorded against total and harmful infestation, but not against the active one. Eventually, neither kaolin nor spinosad were shown to have a particular detrimental effect against naturally occurring B. oleae parasitoids.

Preliminary Molecular Survey of the Possible Presence of Xylella fastidiosa in the Upper Ionian Coasts of Calabria, Italy, through the Capture and Analysis of Its Main Vector Insects.

Xylella fastidiosa subsp. pauca, strain CoDiRO is the bacterium responsible for the onset of the disease known as the olive quick decline syndrome, which has been causing a phytosanitary and economic emergency in the Apulia region since 2013. To date, three insect species have been identified as pathogenic carriers of X. fastidiosa. With the advancement of the infection front, and the possibility of pathogenic insects being "hitchhiked" over long distances, the monitoring of the vectors of X. fastidiosa in the Italian regions bordering Apulia is an increasingly contingent issue for the rapid containment of the bacterium and the protection of the olive-growing heritage. Accordingly, the present research concerned the capture and recognition of the vector insects of X. fastidiosa in the upper Ionian coasts of Calabria (Italy) to evaluate the possible presence of the bacterium through molecular diagnostic techniques. The sampling allowed us to ascertain the presence of Philaenus spumarius and Neophilaenus campestris and their preferential distribution in olive groves and meadows, whereas all the 563 individuals tested negative for the pathogen.