Publisher Correction: Control of laser plasma accelerated electrons for light sources.

The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read 'A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-ß) x ß: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, ß should be bold as well.' The correct version is 'A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.'This has been corrected in both the PDF and HTML versions of the Article.

Control of laser plasma accelerated electrons for light sources.

With gigaelectron-volts per centimetre energy gains and femtosecond electron beams, laser wakefield acceleration (LWFA) is a promising candidate for applications, such as ultrafast electron diffraction, multistaged colliders and radiation sources (betatron, compton, undulator, free electron laser). However, for some of these applications, the beam performance, for example, energy spread, divergence and shot-to-shot fluctuations, need a drastic improvement. Here, we show that, using a dedicated transport line, we can mitigate these initial weaknesses. We demonstrate that we can manipulate the beam longitudinal and transverse phase-space of the presently available LWFA beams. Indeed, we separately correct orbit mis-steerings and minimise dispersion thanks to specially designed variable strength quadrupoles, and select the useful energy range passing through a slit in a magnetic chicane. Therefore, this matched electron beam leads to the successful observation of undulator synchrotron radiation after an 8 m transport path. These results pave the way to applications demanding in terms of beam quality.

Molecular characterization of two distinct strains of blueberry scorch virus (BlScV) in northern Italy.

During blueberry scorch virus (BlScV) surveys of highbush blueberries in Italy between 2005 and 2010, we initially discovered infected orchards only in Piedmont. Since 2009, however, three infected orchards have also been found in Trentino, where a new host species, Vaccinium ashei, was found to be infected by BlScV. Molecular characterization of isolates during the study period suggests that two very distinct epidemics are now present in Italy: the Piedmont isolates belong to a new BlScV strain, whereas the Trentino isolates are almost identical to the Washington State strain.

Epidemiology of flavescence dorée in vineyards in northwestern Italy.

ABSTRACT A serious outbreak of flavescence dorée (FD) was reported in Piemonte, northwestern Italy, in 1998, and since then, the disease has compromised the economy of this traditional wine-growing area, even following the application of compulsory insecticide treatments to control Scaphoideus titanus, the vector of the causal phytoplasma. Affected vines show severe symptoms, varying according to the cultivar, and are rogued to reduce disease spread. Following winter and pruning, a previously affected vine may appear symptomless and free of phytoplasmas in its aerial as well as its root system, even by nested-polymerase chain reaction assays. Such plants are considered to be "recovered". Since 1998 homogenous data on the incidence of newly infected, healthy, or recovered plants productivity, presence of vectors, and treatment schedules have been collected in seven severely affected vineyards of southern Piemonte for 5 years (1999 to 2003). Infectivity and recovery rates were also calculated each year. From 1999 to 2003, the average number of healthy plants decreased and the numbers of recovered plants and those with symptoms increased. Productivity of recovered vines, although lower than that of healthy ones, was always higher than that of vines with symptoms and was not influenced by the time elapsed from date of recovery. The relationships between the ln-transformed number of vectors trapped in the vineyards the previous year and the infection and the recovery rates were fitted by an exponential (R(2) = 0.95) and an asymptotic (R(2) = 0.93) model, respectively.

Occurrence of Lily mottle virus in Escarole.

Lily mottle virus (LMoV), genus Potyvirus, an important virus of lily that also causes flower-breaking in tulip (1), is considered to have a natural host range restricted to the family Liliaceae. In 1996, escarole (Cichorium endivia L. var. latifolium LAM) plants growing in fields close to Torino, Italy, and showing mosaic and necrotic spots on outer leaves were infected by a potyvirus related to LMoV. The virus was identified by immunoelectron microscopy (IEM) done on experimentally infected Nicotiana benthamiana and Chenopodium quinoa. The virus isolated from escarole (LMoV-E) had an experimental host range similar to that of lily isolates of LMoV, although species within the Liliaceae were not tested. LMoV-E systemically infected all nine escarole cultivars and six of seven endive cultivars (C. endivia L. var. crispum LAM) but did not infect any of six lettuce and two chicory cultivars (C. intybus L. var. foliosum HEGI). Symptoms ranged from mild to severe mosaic and were generally more severe on escarole than on endive. Some of the same escarole, endive, and lettuce cultivars were inoculated with a typical LMoV isolate from lily (Le97/49, from A. F. L. M. Derks, the Netherlands), which induced mild systemic infections in only one escarole and one endive cultivar. Both cultivars were also susceptible to LMoV-E. LMoV-E was purified from N. benthamiana, and an antiserum was prepared. IEM decoration titer experiments were done with LMoV-E and four other LMoV isolates from Liliaceae and their homologous antisera. Heterologous titers ranging from identity to serological differentiation index values of 2 to 4 were obtained, confirming the identity of the escarole isolate as a LMoV strain and indicating considerable serological variability among LMoV isolates. In a field survey of endive and escarole crops in 1998, in the area where LMoV-E was first identified, the virus was again detected by enzyme-linked immunosorbent assay in 4 of 80 escarole plants tested. LMoV-E appears to be a LMoV strain particularly adapted to escarole. To our knowledge, this is the first report of LMoV identified in a naturally infected host outside monocotyledonous plants. Reference: (1) E. L. Dekker et al. J. Gen. Virol. 74:881, 1993.

Additional Ornamental Species as Hosts of Impatiens Necrotic Spot Tospovirus in Italy.

Impatiens necrotic spot (INSV) and tomato spotted wilt (TSWV) tospoviruses are among the most important viral pathogens of glasshouse ornamental plants worldwide (1). Tospovirus infections drastically reduce the market value of plants and create certification problems for international traders. As with TSWV, the number of natural host species recorded for INSV is steadily increasing (2). In 1998, severe INSV infections were found on different ornamental plants in glasshouses in the Piedmont Region of northwestern Italy, together with heavy infestations of the thrips Frankliniella occidentalis. A high proportion of plants were infected with INSV, as shown by enzyme-linked immunosorbent assay (ELISA) with polyclonal antisera and monoclonal antibodies against its nucleocapsid protein. Results were confirmed by sap-inoculation to indicator hosts. Some species were already known to be susceptible to INSV, but others are apparently new hosts (2): Ageratum houstonianum (Asteraceae), showing small necrotic rings and leaf malformation; Cordyline terminalis (Agavaceae), showing chlorotic-necrotic ringspots and leaf malformation; Dianthus chinensis (Caryophyllaceae), showing stunting, mosaic, and leaf malformation (some plants had symptomless infections); Episcia capreata (Gesneriaceae), showing necrotic spots on stems and leaves; Godetia grandiflora (Onagraceae), showing necrotic rings; Maranta leuconeura (Marantaceae), showing chlorotic-necrotic spots and apical malformation; Peperomia obtusifolia (Piperaceae), showing necrotic ringspots and leaf malformations; Scindapsus aureus (Araceae), showing necrotic spots and rings; Torenia fournieri (Scrophulariaceae), showing necrosis on stems and apexes. Thrips feeding damage was high on some species, particularly those showing necrotic ringspot symptoms. It often was difficult to distinguish between true systemic symptoms and local INSV infection at thrips feeding sites. Capsicum sp., Coleus blumei, and Dahlia sp., which also were infected in our study, are species known to be infrequent hosts of INSV (2). References: (1) M. L. Daughtrey et al. Plant Dis. 81:1220, 1997. (2) D. Peters. 1998. Pages 107-110 in: Abstr. 4th Int. Symp. Tospovirus Thrips Floral Vegetable Crops. University of Wageningen, The Netherlands.