Correction: Estimation of the dispersal distances of an aphid-borne virus in a patchy landscape.

[This corrects the article DOI: 10.1371/journal.pcbi.

Multi-scale spatial genetic structure of the vector-borne pathogen 'Candidatus Phytoplasma prunorum' in orchards and in wild habitats.

Inferring the dispersal processes of vector-borne plant pathogens is a great challenge because the plausible epidemiological scenarios often involve complex spread patterns at multiple scales. The spatial genetic structure of 'Candidatus Phytoplasma prunorum', responsible for European stone fruit yellows disease, was investigated by the application of a combination of statistical approaches to genotype data of the pathogen sampled from cultivated and wild compartments in three French Prunus-growing regions. This work revealed that the prevalence of the different genotypes is highly uneven both between regions and compartments.

Estimation of the dispersal distances of an aphid-borne virus in a patchy landscape.

Characterising the spatio-temporal dynamics of pathogens in natura is key to ensuring their efficient prevention and control. However, it is notoriously difficult to estimate dispersal parameters at scales that are relevant to real epidemics. Epidemiological surveys can provide informative data, but parameter estimation can be hampered when the timing of the epidemiological events is uncertain, and in the presence of interactions between disease spread, surveillance, and control.

Molecular test to assign individuals within the Cacopsylla pruni complex.

Crop protection requires the accurate identification of disease vectors, a task that can be made difficult when these vectors encompass cryptic species. Here we developed a rapid molecular diagnostic test to identify individuals of Cacopsyllapruni (Scopoli, 1763) (Hemiptera: Psyllidae), the main vector of the European stone fruit yellows phytoplasma. This psyllid encompasses two highly divergent genetic groups that are morphologically similar and that are characterized by genotyping several microsatellite markers, a costly and time-consuming protocol.

Mediterranean and central-eastern European countries host viruses of two different clades of plum pox virus strain M.

The genetic diversity of plum pox virus strain M (PPV-M) was assessed by analyzing 28 isolates collected in 8 European countries. Two genomic fragments spanning the (Cter)P3-6K1-(Nter)CI coding region as well as the full coat protein coding region were sequenced directly from PCR products. Phylogenetic analysis showed that the geographical origin of the collected isolates was clearly associated with two different PPV-M clades.

Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and supports the existence of inter-species recombination.

The genetic diversity of three temperate fruit tree phytoplasmas 'Candidatus Phytoplasma prunorum', 'Ca. P. mali' and 'Ca.

Nine polymorphic microsatellite loci from the psyllid Cacopsylla pruni (Scopoli), the vector of European stone fruit yellows.

Cacopsylla pruni is the vector of European stone fruit yellows, a quarantine disease of Prunus trees. Nine polymorphic microsatellite markers were developed from enriched DNA libraries. Allelic variability was assessed in a collection of 149 females obtained from five localities covering a large geographical area in France.

Specific detection and quantification of the phytopathogenic agent 'Candidatus Phytoplasma prunorum'.

'Candidatus Phytoplasma prunorum' is a wall-less bacterium associated with European stone fruit yellows (ESFY), a severe disease of Prunus spp. (mainly apricot and Japanese plum trees). It can be spread by one insect vector, Cacopsylla pruni, and by the trade of infected material.

Efficient transmission of 'Candidatus phytoplasma prunorum' Is delayed by eight months due to a long latency in its host-alternating vector.

Understanding at which spatiotemporal scale a disease causes significant secondary spread has both theoretical and practical implications. We investigated this issue in the case of European stone fruit yellows (ESFY), a quarantine vector-borne phytoplasma disease of Prunus trees. Our work was focused on the processes underlying disease spread: the interplay between the life cycles of the pathogen ('Candidatus Phytoplasma prunorum') and of the vector (Cacopsylla pruni).

Identifying risk factors for European stone fruit yellows from a survey.

ABSTRACT European stone fruit yellows (ESFY) is becoming a major economic problem for Prunus growers in Europe. The causal agent ("Candidatus Phytoplasma prunorum") and its vector (Cacopsylla pruni) have been identified, but the present knowledge of the risk factors for this disease relies, at best, on specific experiments. To assess the relative significance of several factors correlated with ESFY incidence in the field, an exhaustive survey was performed on apricot and Japanese plum orchards in the Crau plain (France).

Factors Affecting the Spread of Plum pox virus Strain M in Peach Orchards Subjected to Roguing in France.

ABSTRACT We evaluated the impact of roguing on the spread and persistence of the aggressive Plum pox virus strain M (PPV-M) in 19 peach orchard blocks in Southern France. During a 7- to 10-year period, orchards were visually inspected for PPV symptoms, and symptomatic trees were removed every year. Disease incidence was low in all orchards at disease discovery and was <1% in 16 of the 19 orchard blocks.

Spatial Pattern Analysis of Sharka Disease (Plum pox virus Strain M) in Peach Orchards of Southern France.

ABSTRACT The spatial pattern of Sharka disease, caused by Plum pox virus (PPV) strain M, was investigated in 18 peach plots located in two areas of southern France. PPV infections were monitored visually for each individual tree during one to three consecutive years. Point pattern and correlation-type approaches were undertaken using the binary data directly or after parsing them in contiguous quadrats of 4, 9, and 16 trees.

Investigating Disease Spread between Two Assessment Dates with Permutation Tests on a Lattice.

ABSTRACT Mapping and analyzing the disease status of individual plants within a study area at successive dates can give insight into the processes involved in the spread of a disease. We propose a permutation method to analyze such spatiotemporal maps of binary data (healthy or diseased plants) in regularly spaced plantings. It requires little prior information on the causes of disease spread and handles missing plants and censored data.

Distinct viral populations differentiate and evolve independently in a single perennial host plant.

The complex structure of virus populations has been the object of intensive study in bacteria, animals, and plants for over a decade. While it is clear that tremendous genetic diversity is rapidly generated during viral replication, the distribution of this diversity within a single host remains an obscure area in this field of science. Among animal viruses, only Human immunodeficiency virus and Hepatitis C virus populations have recently been thoroughly investigated at an intrahost level, where they are structured as metapopulations, demonstrating that the host cannot be considered simply as a "bag" containing a homogeneous or unstructured swarm of mutant viral genomes.

Geographically and temporally distant natural recombinant isolates of Plum pox virus (PPV) are genetically very similar and form a unique PPV subgroup.

Natural recombinant Plum pox virus (PPV) isolates were detected in Albania, Bulgaria, Czech Republic, Germany, Hungary and Slovakia. Despite different geographical origins and dates of isolation, all the recombinant isolates were closely related at the molecular level and shared the same recombination breakpoint as well as a typical signature in their N-terminal coat protein sequence, suggesting a common origin. Biological assays with four recombinant isolates demonstrated their capacity to be aphid-transmitted to various Prunus hosts.