Sustainable Management of Plant Quarantine Pests: The Case of Olive Quick Decline Syndrome

Luvisi, Andrea; Nicolì, Francesca; Bellis, Luigi De

doi:10.3390/su9040659

Cited by 37 publications

(18 citation statements)

References 85 publications

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“…Recently, X . fastidiosa was reported under field conditions in Italy (Apulia region), associated with severe cases of Olive Quick Decline Syndrome (OQDS) 10,11 ; although the primary role of the bacterium in occlusions formation has been observed 12 , the pathogenesis and symptom formation in olive trees represent research challenges 13 and mechanisms as vessel embolism induced by the pathogen have never been investigated in this host-pathogen association. The main objective of this work was to evaluate constitutive cavitation susceptibility and activation of refilling mechanisms to restore hydraulic conductivity in olive plants subjected to Xylella fastidiosa infection; the comparison between Cellina di Nardò and Leccino, respectively susceptible and resistant olive cultivars 13,14 , aimed to know if cavitation could play a role in determining the severity of symptoms caused by X .…”

Section: Introductionmentioning

confidence: 99%

Xylem cavitation susceptibility and refilling mechanisms in olive trees infected by Xylella fastidiosa

Sabella

Aprile

Genga

et al. 2019

Sci Rep

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In olive trees, Xylella fastidiosa colonizes xylem vessels and compromises water transport causing the olive quick decline syndrome (OQDS). The loss of hydraulic conductivity could be attributed to vessel occlusions induced both by the bacteria biofilm and by plant responses (tyloses, gums, etc.) that could trigger embolism. The ability of the infected plants to detect embolism and to respond, by activating mechanisms to restore the hydraulic conductivity, can influence the severity of the disease symptomatology. In order to investigate these mechanisms in the X . fastidiosa -resistant olive cultivar Leccino and in the susceptible Cellina di Nardò, sections of healthy olive stems were analysed by laser scanning microscope to calculate the cavitation vulnerability index. Findings indicated that the cultivar Leccino seems to be constitutively less susceptible to cavitation than the susceptible one. Among the vascular refilling mechanisms, starch hydrolysis is a well-known strategy to refill xylem vessels that suffered cavitation and it is characterized by a dense accumulation of starch grains in the xylem parenchima; SEM-EDX analysis of stem cross-sections of infected plants revealed an aggregation of starch grains in the Leccino xylem vessels. These observations could indicate that this cultivar, as well as being anatomically less susceptible to cavitation, it also could be able to activate more efficient refilling mechanisms, restoring vessel’s hydraulic conductivity. In order to verify this hypothesis, we analysed the expression levels of some genes belonging to families involved in embolism sensing and refilling mechanisms: aquaporins, sucrose transporters, carbohydrate metabolism and enzymes related to starch breakdown, alpha and beta-amylase. The obtained genes expression patterns suggested that the infected plants of the cultivar Leccino strongly modulates the genes involved in embolism sensing and refilling.

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Section: Introductionmentioning

confidence: 99%

Xylem cavitation susceptibility and refilling mechanisms in olive trees infected by Xylella fastidiosa

Sabella

Aprile

Genga

et al. 2019

Sci Rep

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“…To prevent exotic forest pathogens from entering a country a range of tools have been developed and applied. Pathway models (Douma et al, 2016 and references therein) are used in pest risk assessment enabling monitoring and quarantine actions (Burgess & Wingfield, 2002;Luvisi, Nicolì, & Bellis, 2017;Rimbaud et al, 2015) to target the highest risk pathways of entry. Such methods do not guarantee that no infected trees are imported and enter the trade-network.…”

Section: Discussionmentioning

confidence: 99%

Variability in commercial demand for tree saplings affects the probability of introducing exotic forest diseases

Chávez

Gilligan

Bosch

2018

Journal of Applied Ecology

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Several devastating forest pathogens are suspected or known to have entered the UK through imported planting material. The nursery industry is a key business of the tree trade network. Variability in demand for trees makes it difficult for nursery owners to predict how many trees to produce in their nursery. When in any given year, the demand for trees is larger than the production, nursery owners buy trees from foreign sources to match market demand. These imports may introduce exotic diseases.We have developed a model of the dynamics of plant production linked to an economic model. We have used this to quantify the effect of demand variability on the risk of introducing an exotic disease.We find that: (a) When the cost of producing a tree in a UK nursery is considerably smaller than the cost of importing a tree (in the example presented, less than half the importing cost), the risk of introducing an exotic disease is hardly affected by an increase in demand variability. (b) When the cost of producing a tree in the nursery is smaller than, but not very different from the cost of importing a tree, the risk of importing exotic diseases increases with increasing demand variability. Synthesis and applications. Our model and results demonstrate how a balanced management of demand variability and costs can reduce the risk of importing an exotic forest disease according to the management strategy adopted. For example, a management strategy that can reduce the demand variability, the ratio of production to import cost or both, optimizes the nursery gross margin when mainly own‐produced trees are commercialized. This can also translate into a reduction of the risk of introducing exotic forest diseases due to the small number of imported trees for sale.

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“…The pathogen threat involves the reduction of crop yield, causing the wilting and death of olive trees (olive quick decline syndrome), but the side effects related to the management of the disease are not irrelevant, causing a significant alteration of the agroecosystems [36]. In particular, X. fastidiosa in Salento is directly impacting the environment (i.e., increment of chemical distributions for insect control or fertilization practices, uprooting of diseased plants with relevant impact on production patterns), while the indirect impacts may involve tourism, which is a significant part of the Italian gross domestic product (GDP) (i.e., due to changes in landscape) [38]. Further issues due to X. fastidiosa spread are related to social implications, due to the long historical and cultural connection of olive trees with the area, generating public resistance to uprooting diseased plants [38].…”

Section: Study Areamentioning

confidence: 99%

GIS Analysis of Land-Use Change in Threatened Landscapes by Xylella fastidiosa

Maggiore¹,

Semeraro

Aretano

et al. 2019

Sustainability

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Land-use/land-cover analysis using Geographic Information System (GIS) application can describe and quantify the transformation of the landscape, evaluating the effectiveness of municipal planning in driving urban expansion. This approach was applied in the municipality of Spongano (Salento, South Italy) in order to evaluate the spatial heterogeneity and the transformations of the land use/land cover from 1988 to 2016. This approach was also used to examine the spread of Xylella fastidiosa, which is a plant pathogen of global importance that is reshaping the Salento landscape. The land-use maps are based on the CORINE Land Cover project classification, while the topological consistency was verified through field surveys. A change detection analysis was carried out using the land-use maps of 1988 and 2016. The most extensive land-use class is olive groves (34–36%), followed by non-irrigated arable lands and shrub and/or herbaceous vegetation associations. The main transition of land involved non-irrigated arable lands, which lost 76 ha and 23 ha to shrub and olive areas, respectively. Meanwhile, the artificial surfaces class doubled its extension, which involved mainly the transition from shrub and heterogeneous agricultural areas. However, the olive groves class is threatened by the dramatic phytosanitary condition of the area, indicating a compromised agroecosystem, which is causing a de facto transition into unproductive areas. The results highlight the inconsistency between what was planned by the urban plan in the past and how the landscape of Spongano has been changed over time. This evidence suggests that it is necessary to develop a plan based on learning by doing, in order to shape and adapt the processes of territorial transformation to the unpredictability of the ecologic, social, and economic systems, as well as ensure that these processes are always focused on environmental issues.

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Sustainable Management of Plant Quarantine Pests: The Case of Olive Quick Decline Syndrome

Cited by 37 publications

References 85 publications

Xylem cavitation susceptibility and refilling mechanisms in olive trees infected by Xylella fastidiosa

Xylem cavitation susceptibility and refilling mechanisms in olive trees infected by Xylella fastidiosa

Variability in commercial demand for tree saplings affects the probability of introducing exotic forest diseases

GIS Analysis of Land-Use Change in Threatened Landscapes by Xylella fastidiosa

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