Search results for "Xylella fastidiosa"
showing 8 items of 8 documents
In-Field and Early Detection of Xylella fastidiosa Infections in Olive Using a Portable Instrument
2019
Xylella fastidiosa subsp. pauca (Xfp) is a gram-negative pathogenic bacteria responsible for serious diseases (Purcell, 2013) that inflicts considerable economic loss (Li et al., 2007; Luvisi et al., 2017). The pathogen has been linked to olive quick decline syndrome (OQDS). This devastating olive disease was first observed in Salento (Apulia, southeastern Italy) in 2009. Infected trees respond to Xfp infection with scattered desiccation of twigs and small branches in the upper crown, which extend to the rest of the canopy, showing the characteristic blight effect. The disease causes tree death within a few years from the onset of symptoms (Martelli, 2016). The primary agronomic procedure f…
Updated pest categorisation of Xylella fastidiosa
2018
Abstract Following a request from the European Commission, the EFSA Plant Health Panel updated its pest categorisation of Xylella fastidiosa, previously delivered as part of the pest risk assessment published in 2015. X. fastidiosa is a Gram‐negative bacterium, responsible for various plant diseases, including Pierce's disease, phony peach disease, citrus variegated chlorosis, olive quick decline syndrome, almond leaf scorch and various other leaf scorch diseases. The pathogen is endemic in the Americas and is present in Iran. In the EU, it is reported in southern Apulia in Italy, on the island of Corsica and in the Provence‐Alpes‐Côte d'Azur region in France, as well as in the Autonomous r…
Tracking the outbreak. An optimized delimiting survey strategy for Xylella fastidiosa
2020
SummaryCurrent legislation enforces the implementation of intensive surveillance programs for quarantine plant pathogens. After an outbreak, surveys are implemented to delimit the geographic extent of the pathogen and execute disease control. The feasibility of control programs is highly dependent on budget availability, thus it is necessary to target and optimize surveillance strategies.A sequential adaptive delimiting survey involving a three-phase and a two-phase design with increasing spatial resolution was developed and implemented for the Xylella fastidiosa outbreak in Alicante, Spain. Inspection and sampling intensities were optimized using simulation-based methods and results were v…
Barrier effects on the spatial distribution of Xylella fastidiosa in Alicante, Spain
2021
AbstractSpatial models often assume isotropy and stationarity, implying that spatial dependence is direction invariant and uniform throughout the study area. However, these assumptions are violated when dispersal barriers are present in the form of geographical features or disease control interventions. Despite this, the issue of non-stationarity has been little explored in the context of plant health. The objective of this study was to evaluate the influence of different barriers in the distribution of the quarantine plant pathogenic bacterium Xylella fastidiosa in the demarcated area in Alicante, Spain. Occurrence data from the official surveys in 2018 were analyzed with four spatial Baye…
Characterization and variation of bacterial and fungal communities from the sapwood of Apulian olive varieties with different susceptibility toXylell…
2020
AbstractEndophytes are symptomless fungal and/or bacterial microorganisms found in almost all living plant species. The symbiotic association with their host plants by colonizing the internal tissues has endowed them as a valuable tool to suppress diseases, to stimulate growth, and to promote stress resistance. In this context, the identification of cultivable endophytes residing the sapwood of Apulian olives might be a promising control strategy for xylem colonizing pathogens asXylella fatidiosa. To date, olive’s sapwood cultivable endophytes are still under exploration; therefore, this work pursues a study of diversity and occurrence variation of cultivable endophytes in the sapwood of di…
Apulian olive sapwood endophytes to cope with Xylella fastidiosa: community analysis, antagonists screening, colonization efficiency, and genes expre…
2021
This dissertation comprises a series of studies aimed at exploring the cultivable endophytic communities indigenous to the sapwood of Apulian olive cultivars, identifying potential antagonists against Xylella fastidiosa, pauca ST53, and demonstrating their colonization efficiency and associated effects on olive defence-related genes. This work starts with an extensive analysis of cultivable sapwood endophytes from resistant and susceptible cultivars distributed across phytosanitary zones in Apulia. After multiple isolation of endophyte colonies, the results were translated into quantitative indicators. It was found that the resistant cultivar 'Leccino' showed high stability and diversity of…
Spatial Bayesian Modeling Applied to the Surveys of Xylella fastidiosa in Alicante (Spain) and Apulia (Italy)
2020
The plant-pathogenic bacterium Xylella fastidiosa was first reported in Europe in 2013, in the province of Lecce, Italy, where extensive areas were affected by the olive quick decline syndrome, caused by the subsp. pauca. In Alicante, Spain, almond leaf scorch, caused by X. fastidiosa subsp. multiplex, was detected in 2017. The effects of climatic and spatial factors on the geographic distribution of X. fastidiosa in these two infested regions in Europe were studied. The presence/absence data of X. fastidiosa in the official surveys were analyzed using Bayesian hierarchical models through the integrated nested Laplace approximation (INLA) methodology. Climatic covariates were obtained from …
Modeling the Spatial Distribution of Xylella fastidiosa: A Nonstationary Approach with Dispersal Barriers
2022
Spatial species distribution models often assume isotropy and stationarity, implying that spatial dependence is direction-invariant and uniform throughout the study area. However, these assumptions are violated when dispersal barriers are present. Despite this, the issue of nonstationarity has been little explored in the context of plant health. The objective of this study was to evaluate the influence of barriers in the distribution of Xylella fastidiosa in the demarcated area in Alicante, Spain. Occurrence data from 2018 were analyzed through spatial Bayesian hierarchical models. The stationary model, illustrating a scenario without control interventions or geographical features, was com…