Transmission of Xylella fastidiosa by naturally infected Philaenus spumarius (Hemiptera, Aphrophoridae) to different host plants.

© 2016 The Authors. Journal of Applied Entomology Published by Blackwell Verlag GmbH. The recent establishment of Xylella fastidiosa subspecies pauca in the southern Italian region of Apulia threatens agricultural crops and the environment. Olive is an important and widespread ancient crop in Italy and, so far, the most impacted host. The meadow spittlebug Philaenus spumarius (Hemiptera, Aphrophoridae) has been identified as a vector of X. fastidiosa in southern Italy; this species is one of the most common potential vectors in Europe. To generate disease management strategies, data on X. fastidiosa transmission by P. spumarius are necessary. Therefore, we carried out transmission experiments by using field-collected spittlebugs in 2014 and 2015 (5 and 11 collection dates, respectively), and transferring groups of insects immediately on to recipient plants. Various host plant species were tested: olive, oleander, sweet orange, grapevine and the stone fruit rootstock GF677 (Prunus persica × Prunus amygdalus). Xylella fastidiosa was detected in all the host plants after insect plant access except for grapevine; infections to sweet orange and stone fruit were not systemic. In 2015, estimates of insect X. fastidiosa infectivity were obtained; the number of PCR-positive P. spumarius on each plant was positively correlated with the plant infection status. The proportion of P. spumarius infected with X. fastidiosa ranged from 25% to 71% during the entire survey period. The number of X. fastidiosa cells detected in P. spumarius heads ranged from 3.5 × 10 to 4.0 × 102(CFU equivalents), which is lower than that reported for leafhopper vectors in the Americas. These data show that field-collected P. spumarius have high rates of X. fastidiosa infection and are competent vectors

First Report of Pseudomonas Grapevine Bunch Rot Caused by Pseudomonas syringae pv. syringae .

Pseudomonas syringae pv. syringae, a Gammaproteobacterium belonging to genomospecies 2 within the P. syringae complex, is distributed worldwide, and it is responsible for bacterial canker on >100 different hosts, including the grapevine. P. syringae pv. syringae induces necrotic lesions in the leaf blades, veins, petioles, shoots, rachis, and tendrils on grapevine cultivars in different areas. P. syringae pv. syringae has been associated with severe economic losses in different grape cultivars in Australia, where it causes inflorescence rot. In midsummer to late summer 2017, symptoms of berry rots differing from those caused by the common berry rots agents were observed in different cultivar Red Globe vineyards of Apulia (southern Italy). As proven by fulfillment of Koch's postulates, these symptoms were caused by a bacterium that, according to the results of biochemical, physiological, nutritional, antimicrobial activity, and pathogenicity tests and sequencing of 16S ribosomal DNA, gyrB, rpoB, and rpoD genes, was identified as P. syringae pv. syringae. This is the first report of Pseudomonas grapevine bunch rot

Thermo-hydraulic modeling of the ITER radial neutron camera

The ITER Radial Neutron Camera (RNC) is a diagnostic system designed as a multichannel detection system to measure the uncollided neutron flux from the plasma, generated in the tokamak vacuum vessel, providing information on neutron emissivity profile. The RNC consists of array of cylindrical collimators located in two diagnostic structures: the ex-port system and the in-port system. The in-port system, contains the diamond detectors which need a temperature protection. Feasibility study of the efficiency of the cooling system for the In-port Detector Modules of the RNC during baking process was the main goal of thermo-hydraulic numerical modeling. The paper presents the concept of the cooling system layout and the original way of integration of numerical thermo-hydraulic analyses of the in-port detector cassette. Due to the large extent of the detector cassette it is impossible to include all relevant thermal and hydraulic effects in one global model with sufficient level of details. Thus the modelling strategy is based on the concept of three stage modelling from details to global model. The presented paper includes results of numerical calculations made with ANSYS Fluent software in order to provide the final answer, including calculation of heat loads in the detector cassette from adjacent walls during baking and normal operation conditions

Isolation and pathogenicity of Xylella fastidiosa associated to the olive quick decline syndrome in southern Italy

In autumn 2013, the presence of Xylella fastidiosa, a xylem-limited Gram-negative bacterium, was detected in olive stands of an area of the Ionian coast of the Salento peninsula (Apulia, southern Italy), that were severely affected by a disease denoted olive quick decline syndrome (OQDS). Studies were carried out for determining the involvement of this bacterium in the genesis of OQDS and of the leaf scorching shown by a number of naturally infected plants other than olive. Isolation in axenic culture was attempted and assays were carried out for determining its pathogenicity to olive, oleander and myrtle-leaf milkwort. The bacterium was readily detected by quantitative polymerase chain reaction (qPCR) in all diseased olive trees sampled in different and geographically separated infection foci, and culturing of 51 isolates, each from a distinct OQDS focus, was accomplished. Needle-inoculation experiments under different environmental conditions proved that the Salentinian isolate De Donno belonging to the subspecies pauca is able to multiply and systemically invade artificially inoculated hosts, reproducing symptoms observed in the field. Bacterial colonization occurred in prick-inoculated olives of all tested cultivars. However, the severity of and timing of symptoms appearance differed with the cultivar, confirming their differential reaction