Search Results (64)

Sometimes, mandatory rules for eradicating pathogens specifically target crops that hold intrinsic economic value, cultural heritage, and are a lucrative tourist attraction as well as an appealing part of the landscape due to their historical presence in the region. An example of this is the introduction of Xylella fastidiosa subsp. pauca (Xfp), mainly vectored by Philaenus spumarius to olive groves in Apulia. Twelve years after the first official report on its presence and numerous studies, this review aims to reconsider some of the quarantine measures in place to prevent the spread of Xfp. Surveys carried out within the demarcated areas have shown a low incidence of Xfp over the years ranging from 0.06% to 0.70%. Furthermore, the bacterium is now present throughout the region, from the south to the north, potentially suggesting that the bacterium may be endemic in the region. Epidemiological models have indicated low or negligible infectivity for asymptomatic trees. Rigorous vector control, achieved through the mechanical removal of eggs and juvenile forms, coupled with the contemporary reduction in the Xfp load within the olive crown using bactericidal compounds, could effectively reduce the spread of Xfp in both infected and demarcated areas. These actions could also serve as preventive measures in current free areas. Once the prevalence of both vectors and Xfp is low, only olive trees in demarcated areas that test positive for the bacterium should be uprooted. Trees within a 50 m radius of an Xfp-positive olive tree should not be removed if they test negative for Xfp upon detection. Full article

Insects rely on a variety of sensory cues for orientation, with antennae playing a central role in receiving and transmitting information about the environment. Philaenus spumarius (Hemiptera: Aphrophoridae), a spittlebug and vector of the bacterium Xylella fastidiosa, has a reduced number of antennal sensilla, yet demonstrates effective multimodal communication through olfactory and vibrational signals. This study aimed to investigate how the simplified sensory system of P. spumarius relates to the primary neuropils of the brain. We examined the ultrastructural organization of Johnston’s organ using scanning and transmission electron microscopy, complemented by previous data on antennal sensilla. Brain organization was investigated by Micro-CT and confocal laser scanning microscopy, which enabled us to identify the primary neuropiles. In addition, we conducted antennal and single sensillum backfills to trace sensory neurons to the brain. Our findings provide insight into the adaptation of a simplified sensory system for effective communication and orientation in P. spumarius. Full article

Several management strategies based on different approaches have been proposed to contain the spread of the pest Xylella fastidiosa, but novel, effective, and sustainable physical methods are still needed. The present study is focused on the design, construction, and testing of an innovative mechanical–aeraulic device which implements a physical vector control strategy against the nymphs of Philaenus spumarius. The developed machine generates an airstream with proper temperature, shape, and velocity to impact the nymphs sheltered in the protective white “spittle” and cause their impairment or death. The machine generates a hot airflow with a temperature of 71.9 °C at 10 cm and 65.4 °C at 30 cm and a speed of 8.6 m s⁻¹ at 10 cm to 6.2 m s⁻¹ at 30 cm from the central axis of the outlet section. The area affected by the hot airflow was 2.65 m², and the recorded mean temperature of the vegetation in this area was 60.2 ± 2 °C. The mean mortality rate of nymphs of Philaenus spumarius reached by using the developed machine was 84.3%. Full article

In recent years, the spread of the phytopathogenic bacterium Xylella fastidiosa Wells et al., 1987 (Bacteria: Proteobacteria, Gammaproteobacteria) has posed a significant threat to olive cultivation in Italy, particularly in regions of high economic and agronomic value such as Apulia (Southern Italy). In this two-year study (2019–2020), we investigated the Auchenorrhyncha community in three representative olive farms in Tuscany (Central Italy), another region with highly valuable olive-growing, comparing traditional (400 trees/ha) and super-high-density (1500 trees/ha) management systems. Adult insects were collected monthly from May to November using sweep net sampling on both olive tree canopies and herbaceous ground cover. In total, 1844 individuals belonging to 25 genera and five families were identified. Philaenus spumarius L. and Neophilaenus campestris (Fallén) (Cercopoidea: Aphrophoridae) were confirmed as the most prevalent X. fastidiosa vectors in each site. However, data analysis revealed that Auchenorrhyncha community composition was significantly influenced by site and vegetation stratum, but not by olive grove management systems. These findings contribute to a deeper understanding of the composition of Auchenorrhyncha communities associated with olive groves, highlighting that new super-high-density management does not influence the presence and abundance of X. fastidiosa vectors. Full article

Xylella fastidiosa was first detected in Portugal in 2019 in Lavandula dentata. In response, the national plant health authorities promptly established a Demarcated Zone in the affected area and implemented a series of eradication and control measures, including the systematic removal and destruction of infected and host plants. This study analyzes the economic and operational impacts of these eradication efforts in the northern region of Portugal, with a focus on Demarcated Zones such as the Porto Metropolitan Area, Sabrosa, Alijó, Baião, Mirandela, Mirandela II, and Bougado between 2019 and June 2023. During this period, about 412,500 plants were uprooted. The majority were Pteridium aquilinum (bracken fern), with 360,324 individuals (87.3%), reflecting its wide distribution and the large area affected. Olea europaea (olive tree) was the second most common species removed, with 7024 plants (1.7%), highlighting its economic relevance. Other notable species included Quercus robur (3511; 0.85%), Pelargonium graveolens (3509; 0.85%), and Rosa spp. (1106; 0.27%). Overall, destruction costs were estimated at about EUR 1.04 million, with replanting costs of roughly EUR 6.81 million. In parallel, prospection activities—conducted to detect early signs of infection and monitor disease spread—generated expenses of roughly EUR 5.94 million. While prospecting represents a significant financial investment, the results show that it is considerably more cost-effective than large-scale eradication. Prospection enables early detection and containment, preventing the widespread destruction of vegetation and minimizing disruption to agricultural production, biodiversity, and local communities. Importantly, our findings reveal a sharp decline in confirmed cases in the initial outbreak area—the Porto Demarcated Zone—from 124 cases in 2019 to just 5 in 2023, indicating the effectiveness of the eradication and monitoring measures implemented. However, the presence of 20 active Demarcated Zones across the country as of 2023 highlights the continued risk of spread and the need for sustained vigilance. The complexity of managing Xylella fastidiosa across ecologically and logistically diverse territories justifies the high costs associated with surveillance and targeted interventions. This study reinforces the strategic value of prospection as a proactive and sustainable tool for plant health management. Effective surveillance requires the integration of advanced methodologies aligned with the phenological stages of host plants and the biological cycle of vectors. Targeting high-risk locations, optimizing sample numbers, ensuring diagnostic accuracy, and maintaining continuous training for field teams are critical for improving efficiency and reducing costs. Ultimately, the findings underscore the need to refine and adapt monitoring and eradication strategies to contain the pathogen, safeguard agricultural systems, and prevent Xylella fastidiosa from becoming endemic in Portugal. Full article

To date, Philaenus spumarius (Linnaeus, 1758), Philaenus italosignus Drosopoulos & Remane, 2000, and Neophilaenus campestris (Fallén, 1805) are proven vectors of the phytopathogenic bacterium Xylella fastidiosa Wells et al., 1987 in Europe. Currently, the identification of these three species relies on the well-documented status of morphological and taxonomical characters, making the discrimination of vector adult males possible by genitalia comparison. This study updates the biomolecular diagnostic tests with a rapid identification tool for P. italosignus, using locked nucleic acid (LNA) probe technology. The test also overcomes the difficulties associated with the morphological identification of females and juveniles. The morphological α-taxonomic identification of the male, achieved through comparison with the type of the species, retains its primary role in specimen identification for probe building. Later, the proposed assay can contribute to the rapid identification of P. italosignus by the secondary (molecular) identification step. The new LNA qPCR test offers high reliability and reproducibility in the identification of P. italosignus instars, thus improving targeted surveys of X. fastidiosa vector populations and allowing discrimination between species collected in the field. The accurate identification and census of vector individuals, regardless of their gender and instar, enhances the efficacy of Xylella IPM-DSS (Integrated Pest Management Decision Support System) strategies. Full article

Xylella fastidiosa (Xf) is a Gram-negative bacterium responsible for severe diseases in several commercially significant crops, including olive, grapevine, citrus and almond. Its management is particularly challenging due to its transmission via widespread vector insects, its ability to form biofilms, its high genetic diversity and, sometimes, latent symptoms. Current control strategies focus on integrated and preventive approaches, including the use of resistant varieties, agronomic practices, and vector control through chemical and biological methods. Direct control of the bacterium has always been a complex challenge that includes strategies to limit vector presence and activity in the field; however, several compounds have recently been evaluated that are able to inhibit biofilm formation and Xf growth. This review provides an up-to-date summary of studies investigating the efficacy of various treatments based on organic compounds, synthetic molecules and salt- or metal-based formulations. By evaluating the results of in vitro and in vivo experiments, the most promising solutions were identified that address the main challenges and limitations of chemical control strategies. These include N-acetylcysteine and zinc- and copper-based formulations, which are effective and potentially transferable to the field for crops such as citrus and olive trees. Antimicrobial peptides and nanoparticles, on the other hand, have demonstrated high efficacy in vitro, although further studies directly in the field are required. The evidence emerging from the analyzed studies offer insights to guide future research towards more effective and sustainable management approaches to mitigate the spread and impact of Xf. Full article

The introduction of non-native species like Xylella fastidiosa to new environments can lead to potentially catastrophic ecological and economic repercussions. This work comprehended the prospection phase (insect sampling and submission of samples to the laboratory) from X. fastidiosa demarcated zones of Área Metropolitana do Porto; Sabrosa; Alijó; Baião; Mirandela; Mirandela II; and Bougado and the research phase (collecting and organizing data and statistical treatment). The results of this study showed the presence of the bacterium in some tested spittlebugs species captured in DZ of Área Metropolitana do Porto, which highlights the role of the vector in mediating the disease’s propagation. Most insects were found in public gardens and in nurseries/gardens where there is a diverse array of food sources, shelter, mating locations, and suitable substrates for egg laying that serve as ideal conditions for the population of Philaenus spumarius. We observed that most insects were found in the first trimester (36.5%), followed by the third trimester (23.2%). Finally, it was shown that, in our study, the most frequent host plants where insects were found included Lavandula dentata, Ulex minor, Ulex europaeus, Quercus suber, Plantago lanceolata. Our findings imply a robust connection between plant communities, ecological conditions, and insect populations with the occurrence of Xylella fastidiosa, particularly within the examined climatic context. Full article

Xylella fastidiosa is a vector-borne bacterium causing significant economic losses in global agricultural industries. Management strategies focus primarily on controlling vector populations. The diversity of vector species, their polyphagy, and the wide range of host plants supporting bacterial development make X. fastidiosa pathosystems particularly challenging to manage. Understanding vector and host plant relationships is key to developing effective strategies. This study examined the oviposition strategies, host preferences, and nymphal development of Europe’s main X. fastidiosa vectors, Philaenus spumarius and Neophilaenus campestris, under semi-field conditions (screenhouse). The two species exhibited distinct behaviors. Neophilaenus campestris primarily laid eggs on its preferential host, the grass Festuca arundinacea, while P. spumarius preferred dry soil substrates, irrespective of the host plant species. The presence of multiple hosts reduced the oviposition rates of P. spumarius compared with single-host scenarios. The nymphs of P. spumarius quickly identified and settled on preferential hosts, while the N. campestris nymphs initially moved randomly but later congregated on their preferred host. Despite their polyphagy, nymph survival was limited to preferential hosts. These findings highlight opportunities for habitat management strategies, such as enhancing plant diversity and eliminating overwintering egg sites, to mitigate vector populations and limit the spread of X. fastidiosa. Full article

Xylella fastidiosa (Xf) is a xylem-limited Gram-negative phytopathogen responsible for severe plant diseases globally. Colonization and dissemination on host plants are regulated primarily by diffusible signal factors (DSFs) and quorum sensing (QS) molecules regulating biofilm formation, motility, and virulence factor synthesis. DSFs play a critical role in the transition of bacteria from adhesion to dispersal phases, influencing plant infection and transmission by vector. Because of Xf’s host range (over 550 plant species), effective containment strategies are highly demanded. In this review, we discuss the molecular mechanism of DSF-mediated signalling in Xf, especially concerning its role in pathogenicity and adaptation. Moreover, we shed light on innovative approaches to manage Xf, including quorum-quenching (QQ) strategies and transgenic plants targeted to disrupt QS pathways. Improved knowledge of DSF interactions with host plants and bacterial communities could provide an entry point for novel, sustainable disease control strategies to decrease Xf’s agricultural and ecological impact. Full article

Xylella fastidiosa (XF) is a Gram-negative bacterium responsible for severe plant diseases affecting a wide range of host plants, some of them important crops. Since 2017, only the pauca subspecies (ST80) have been identified in Ibiza. XF is naturally transmitted by xylem sap-feeding insects; among them, only Philaenus spumarius (PS) and Neophilaenus campestris Fallén (NC) have been reported as potential insect vectors for XF in Ibiza. This study aims to investigate the dissemination of XF and to propose effective control strategies. The crops and the surrounding vegetation were sampled for potential vectors. DNA from insects was extracted and amplified by three qPCR methods, allowing subspecies identification. The results confirmed the continuous presence of adults of PS and NC in Ibiza and Formentera from May to December with important populations. During the summer period, PS captures predominantly took place within the surrounding woody vegetation adjacent to the plots. The main host plant for PS was Pinus halepensis Miller in Ibiza and Juniperus phoenicea subsp. turbinata (Guss.) Nyman in Formentera. In Ibiza, off the total PS captures, 4.47% tested positive for XF. These results confirm that PS is the main vector of XF on these islands, both in terms of captures and the percentage of positive insects for XF. In Formentera, despite the presence of potential vectors and the proximity and contact with Ibiza, no XF-positive insects were found, confirming the absence of the bacterium on the island. Full article

A three-year study in two Mediterranean peach orchards monitored Auchenorrhyncha species, including the main vectors of plant pathogens causing significant economic losses. The research focused on the management of two polyphagous leafhoppers, Asymmetrasca decedens and Hebata (Signatasca) solani. Yellow sticky traps were used to track species dynamics and assess population trends in relation to meteorological factors such as temperature, rainfall, and humidity. Chemical treatments and early green pruning were evaluated for pest control effectiveness. Fifty-five Auchenorrhyncha species were identified, including vectors of Xylella fastidiosa. H. solani appeared from spring to early summer, and was gradually replaced by A. decedens, which peaked in late summer. Higher temperatures favoured A. decedens, while rainy days significantly reduced its presence. H. solani responded less consistently to meteorological factors, but increased with higher minimum relative humidity, and decreased with higher total humidity. These results highlight the need for targeted chemical control strategies to manage A. decedens during its peak season and the benefits of early green pruning to protect susceptible trees in spring. The results emphasise the role of climate in pest dynamics and provide important insights for IPM programmes to reduce economic losses in Mediterranean peach orchards worldwide. Full article

The study of Auchenorrhyncha species composition in Greek olive orchards is crucial due to the potential threat of Xylella fastidiosa invading the region. Recent studies have begun exploring agricultural landscapes, particularly olive and citrus orchards. From 2016 to 2022, biodiversity surveys were conducted in thirteen olive orchards across three regions of Greece: Peloponnese, Sterea Ellada, and the Northeast Aegean. Malaise traps were installed in each orchard and monitored monthly, supplemented by sweep net sampling in two orchards to capture less mobile species and assess their association with host plants. A total of 14,771 specimens were collected, representing 125 species predominantly feeding on weeds. The dominant species were the Typhlocybinae Hebata decipiens and Zyginidia pullula, while Euscelis lineolata was the most common Deltocephalinae. Aphrophoridae, including Philaenus spumarius and Neophilaenus campestris, were more effectively collected with sweep nets, primarily from Avena sterilis L. This study offers a detailed overview of the Auchenorrhyncha fauna in Greek olive orchards, providing essential insights for developing strategies to prevent the invasion of Xylella fastidiosa. Full article

This study investigated the phenology and population dynamics of potential insect vectors of Xylella fastidiosa Wells et al. and other Auchenorrhyncha species in olive and citrus groves of Chania province, Crete, Greece. Although X. fastidiosa has not been reported in Greece, its introduction could cause serious diseases in many crops, including olives and citrus. Olive groves of Olea europaea L. ‘Koroneiki’ were sampled systematically using sweep net and Malaise traps over 24 months. One citrus grove was sampled for one year using a Malaise trap. Sweep net samples were taken from the herbaceous cover, tree canopy, and field borders of olive groves. Auchenorrhyncha were more abundant on the herbaceous cover compared to the canopy and field margins. Aphrophoridae species were mostly found on the herbaceous cover and in low numbers during fall (October–December) and spring (April–May). Cicadellidae species, such as Euscelis spp., were frequently found on the herbaceous cover of both olive and citrus groves. One Aphrophoridae and several Cicadellidae species were recorded in the citrus grove. Altitude was found to influence the population abundance of some Auchenorrhyncha species in olive groves. These results provide information for effective integrated management of insect vectors and their vector-borne pathogens. Full article

This research study reports new records of eight species of Cicadellini (Hemiptera, Cicadellidae, Cicadellinae) across seven municipalities in Amazonas State, Brazil. Among these species, one is known as a vector of CVC (Provancherana corniculata). Additionally, five species are being reported for the first time in citrus for the State (Erythrogonia sexguttata, Hortensia similis, Provancherana corniculata, Scopogonalia amazonensis, and Scoposcartula oculata), and three species (Diedrocephala variegata, Macugonalia moesta and Xyphon reticulatum) are reported for the first time in the northern region. This research highlights the lack of information on sharpshooter occurrence in the Amazonas region, emphasizing the need for further investigations in this area. Full article