Suchergebnisse

The spittlebug Philaenus spumarius (L.) has been identified as vector for the damaging bacterium X. fastidiosa in Europe. The knowledge about this insect biology and survival developing on native plants from Europe is crucial to establish ground cover management strategies in olive orchards to control the X. fastidiosa spread. In this study we aimed to evaluate the survival of adults developing on two native and common plants in Europe as well as the effect of different temperatures on the P. spumarius survival. The species selected for the survival analysis were Medicago arabica (L.) Huds. and Sanguisor baverrucosa (Link exG.Don) Ces. These plants are distributed all across Europe and presented foams near the campus, where they were collected. New born adults (<24h) were used for survival analysis. Six treatments (M. sativa 21⁰C, M. sativa 25⁰C, S. verrucosa 21⁰C, water 21⁰C, water 25⁰C and water 4⁰C) with 21 to 30 replicates were accomplished. Results indicated that survival of P. spumarius could improve when developing on different plants species. Variation in temperatures also affected the P. spumarius survival, being particularly remarkable the improvement of survival under 4⁰C when compared with the other water treatments. ; This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS". ; info:eu-repo/semantics/publishedVersion

In Portugal chestnut tree (Castanea sativa Miller) has an economic, social and landscape importance. Trás-os-Montes, in the Northeast of the country, is the first Portuguese fruit producer region with 80% of the production. The fruits produced in this region are of high quality, that was been recognized by the European Union with Protected Denomination of Origin "Castanha da Terra Fria ", however, every year the attack of pests is a problem that . cause serious losses. The chestnut moth Laspeyresia (= Cydia) splendana Hubner is the most serious pest of chestnut fruit in several countries.

The "citrus greening disease" or huanglongbing (HLB) is caused by the Gram-negative bacteria Candidatus Liberibacter spp. One vector of HLB, the African citrus psyllid Trioza erytreae (del Guercio, 1918), was recorded for the first time in 2014, in mainland Spain, and since then, it has spread throughout the Iberian Peninsula. Spiders could be natural enemies of T. erytreae. In this work, we assessed the potential of a model spider species, selected according to the most abundant guild in the field, as a natural enemy of T. erytreae. Theridiidae was the most successful family, capturing adults of T. erytreae in the field. Kochiura aulica (Theridiidae) was selected as a model for functional response assays in the laboratory. The effect of web-building plasticity on the functional response of K. aulica was investigated using two types of arena. The spiders developed tubular-like or branch-like webs according to the spatial constraints. The web architecture significantly shifted the trapping efficiency of K. aulica. Functional responses for tubular and branch webs were both Type-II, but more psyllid prey were captured and killed in the tubular webs than in branch webs. In addition, significantly more psyllids survived in branch-like webs. Our results suggest that web architecture is a key factor driving the number of captured adults of the psyllid. Space web builders could be successful natural enemies of T. erytreae, although further research is needed to clarify the influence of web-building plasticity on the functional response and trapping efficiency of spiders. ; The authors are grateful to the European Union grant, programme H2020 entitled: PREHLB: Preventing HLB epidemics for ensuring citrus survival in Europe. H2020-SFS-2018–2 Topic SFS-05–2018-2019–2020—new and emerging risks to plant health (Project nº 817526)—as well as to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and Associated Laboratory SusTEC (LA/P/0007/2020). ...

Xylella fastidiosa, was recently detected in Portugal (January 2019), this phytopathogenic bacterium is a threat to important crops of agricultural interest. It is transmitted by xylem-feeding insects that belong to the suborder Auchenorrhyncha. However, the knowledge about these insects in Portugal is scarce. In this context, the goal of this work was to identify the frequency and biodiversity of Auchenorrhyncha in Trás-os-Montes region, Portugal. For that, in 2018, in Trás-os-Montes region, five olive groves, five almond orchard and five vineyards with ground cover were sampled for adults of Auchenorrhyncha, during three distinct periods (beginning of July, midSeptember and mid-October). Sampling was performed in the ground and in the aerial part of the plants. In each sampling date, 10 samples of 10 sweepings were collected on the ground in each orchard and vineyard. On the aerial part of the orchards 10 samples of 4 sweeping in 6 trees were collected and in the vineyard 10 samples of 50 sweepings were collected. A total of 3741 adults of Auchenorrhyncha were recovered on the three sampling dates. From these, 949 were Fulgoromorpha and 2792 Cicadomorpha, being the highest abundance observed in the beginning of July. In general, the vineyards presented the higher number of individuals of the Cicadomorpha and the olive orchards presented the smaller number of individuals of this infraorder. However, almond orchards presented the higher abundance of confirmed vectors of X. fastidiosa, 16 individuals belonging to the genus Neophilaenus and seven individuals of the genus Philaenus in the three periods. The higher number Philaenus individuals was observed in mid-October on the vegetation cover. ; This work has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XFACTORS". ; info:eu-repo/semantics/publishedVersion

Variation on bacterial communities living in the phyllosphere as epiphytes and endophytes has been attributed to plant host effects. However, there is contradictory or inconclusive evidence regarding the effect of plant genetics (below the species' level) and of plant tissue type on phyllosphere bacterial community assembly, in particular when epiphytes and endophytes are considered simultaneously. Here, both surface and internal bacterial communities of two olive (Olea europaea) cultivars were evaluated in twigs and leaves by molecular identification of cultivable isolates, with an attempt to answer these questions. Overall, Proteobacteria, Actinobacteria and Firmicutes were the dominant phyla, being epiphytes more diverse and abundant than endophytes. Host genotype (at cultivar level) had a structuring effect on the composition of bacterial communities and, in a similar way, for both epiphytes and endophytes. Plant organ (leaf vs. twig) control of the bacterial communities was less evident when compared with plant genotype and with a greater influence on epiphytic than on endophytic community structure. Each olive genotype/plant organ was apparently selective towards specific bacterial operational taxonomic units (OTUs), which may lead to specific feedbacks on fitness of plant genotypes. Bacterial recruitment was observed to happen mainly within epiphytes than in endophytes and in leaves as comparedwith twigs. Such host specificity suggested that the benefits derived fromthe plant– bacteria interaction should be considered at genetic levels below the species. ; The authors are grateful to the FEDER and Foundation for Science and Technology (FCT, Portugal) under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019) and BioISI (UID/MULTI/04046/2013), as well as the Horizon 2020, the European Union's Framework Programme for Research and Innovation, for financial support the project PRIMA/0002/2018 INTOMED—Innovative tools to combat crop pests in the Mediterranean. D. Mina thanks FCT, POPH-QREN and FSE forMSFRH-BD-105341/2014 grant. ; info:eu-repo/semantics/publishedVersion

Olive knot (OK) is a widespread bacterial disease, caused by Pseudomonas savastanoi pv. savastanoi (Pss), which currently has not effective control methods. The use of naturally occurring microbial antagonists, such as bacteria, as biocontrol agents could be a strategy to manage this disease. The objective of this work was to select bacteria from olive tree phyllosphere able to antagonize Pss using in vitro and in planta experiments. The elucidation of their modes of action and the potential relationship between antagonism and bacteria origin has been investigated, as well. To this end, 60 bacterial isolates obtained from the surface and inner tissues of different organs (leaves, twigs, and knots), from two olive cultivars of varying susceptibilities to OK, were screened for their in vitro antagonistic effect against Pss. A total of 27 bacterial strains were able to significantly inhibit Pss growth, being this effect linked to bacteria origin. Strains from OK-susceptible cultivar and colonizing the surface of plant tissues showed the strongest antagonistic potential. The antagonistic activity was potentially due to the production of volatile compounds, siderophores and lytic enzymes. Bacillus amyloliquefaciens P41 was the most effective antagonistic strain and their capacity to control OK disease was subsequently assayed using in planta experiments. This strain significantly reduces OK disease severity (43.7%), knots weight (55.4%) and population size of Pss (26.8%), while increasing the shoot dry weight (55.0%) and root water content (39.6%) of Pss-infected olive plantlets. Bacterial isolates characterized in this study, in particular B. amyloliquefaciens P41, may be considered as promising biocontrol candidates for controlling OK disease. ; This work was funded by FEDER funds through COMPETE (Programa Operacional Factores de Competitividade), national funds through FCT (Fundação para a Ciência e a Tecnologia) and by Horizon 2020, the European Union's Framework Programme for Research and Innovation, within the project PRIMA/0002/2018 (INTOMED – Innovative tools to combat crop pests in the Mediterranean), and the Mountain Research Center – CIMO (UIDB/00690/2020 and UIDB/04046/2020). DM thanks FCT for SFRH-BD-105341/2014 grant. ; info:eu-repo/semantics/publishedVersion

Plant-inhabiting microorganisms interact directly with each other affecting disease progression. However, the role of host plant and plant habitat in shaping pathobiome composition and their implication for host susceptibility/resistance to a particular disease are currently unknown. For the elucidation of these questions, both epiphytic and endophytic bacterial communities, present in asymptomatic and symptomatic twigs from olive cultivars displaying different susceptibilities to olive knot (OK) disease, were investigated using culturing methods. OK disease was the main driver of the bacterial community, causing changes on their diversity, abundance and composition. OK disease effect was most notorious on OK-susceptible cultivar and when considering the endophytic communities. Plant habitat (epiphytes vs. endophytes) also contributed to the bacterial community assembling, in particular on symptomatic twigs (knots) of OK-susceptible cultivar. In contrast, host cultivar had little effect on the bacterial community composition, but OK-symptomatic twigs (knots) revealed to be more affected by this driver. Overall, the pathobiome seems to result from an intricate interaction between the pathogen, the resident bacteria, and the plant host. Specific bacterial genera were associated to the presence or absence of OK disease in each cultivar. Their ability to trigger and/or suppress disease should be studied in the future. ; The authors are grateful to the FEDER and Foundation for Science and Technology (FCT, Portugal) under Programme PT2020 for financial support to CIMO (UIDB/00690/2020) and BioISI (UID/MULTI/04046/2013), as well as the Horizon 2020, the European Union's Framework Programme for Research and Innovation, for financial support the project PRIMA/0002/2018 INTOMED - Innovative tools to combat crop pests in the Mediterranean. D. Mina thanks FCT, POPH-QREN and FSE for SFRH-BD-105341/2014 grant. ; info:eu-repo/semantics/publishedVersion

There is an urgent need of increasing the knowledge about natural enemies of Philaenus spumarius and finding strategies to limit the spread of X. fastidiosa. Generalist predators, such as spiders, can arise as potential natural control agents. Determining the functional response is crucial for understanding the potentiality of a predator as biological control agent. In this work, the functional response of two widespread palearctic spider species belonging to two different functional groups was assessed. The ambusher spider Synema globosum and the orb-weaver Araniella cucurbitina were used as model species and P. spumarius as prey under laboratory conditions. In parallel, Ceratitis capitata was also used as prey in order to compare the spiders´ predatory potential between a non-flying insect (P. spumarius) and a flying one (C. capitata). A. cucurbitina and S. globosum showed a type II and type I functional response respectively when fed with P. spumarius and a type II response when fed with C. capitata. Both the handling time and attack rate were significantly different between spider species when fed with P. spumarius (p<0.01) and between prey types for each spider functional group (p<0.01). The results suggest that S. globosum was more efficient capturing spittlebugs one by one than A. cucurbitina. On the contrary, A. cucurbitina was more efficient killing flies in webs than S. globosum. ; This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS". ; info:eu-repo/semantics/publishedVersion

The Aphrophoridae family contains important vectors of Xylella fastidiosa, a serious bacterial plant disease. In olive orchards, nymphs usually feed on the ground-cover vegetation. However, detailed information about their populations and host/non-host plants in some regions threatened by Xylella, such as the northeast of Portugal, is very limited. The goal of our work was to identify the vector species, nymphal development period, and their host and non-host herbaceous plants in olive orchards from northeastern Portugal. Ground-cover plant species hosting or not hosting nymphs were identified during the spring of 2017 to 2019 in olive orchards. Nymphal development period, nymph aggregation, and nymph's preferred feeding height of the ground-cover plants were recorded. The most abundant Aphrophoridae species was Philaenus spumarius followed by Neophilaenus sp. Nymphs developed from April to early May and showed a low number of individuals per foam (generally between one and three). They preferred the middle part of the plants. Philaenus spumarius feeds preferentially on Asteraceae and Fabaceae, and Neophilaenus sp. on Poaceae. Some abundant plants, such as Bromus diandrus, Astragalus pelecinus, Chrysanthemum segetum, Trifolium spp., Caryophyllaceae, and Brassicaceae, were barely colonized by Aphrophoridae nymphs. This knowledge is essential for the selection of the species composition of ground-cover vegetation to minimize the presence of vectors of X. fastidiosa in olive groves. ; This work was funded by European Union Horizon 2020 research and innovation program under grant agreement no. 727987 XF-ACTORS (Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy), and Foundation for Science and Technology (FCT, Portugal) the financial support by national funds FCT/MCTES to CIMO UIDB/00690/2020. ; info:eu-repo/semantics/publishedVersion

The dangerous phytopathogenic bacteria Xylella fastidiosa (Wells et al., 1987) has been recently detected in Portugal (January 2019). This disease is transmitted horizontally from infected to non-infected plants by xylem-feeders that belong to the suborder Auchenorrhyncha. The information available until now about natural enemies is reduced. In this work the potential natural enemies of Auchenorrhyncha eggs, the most susceptible stage, were studied during the autumn/winter of 2018/2019. For that, from November 2018 to February 2019 before the egg hatching, on a biweekly basis, 10 samples of 50 g of rests of the remaining vegetation in the ground cover, mainly Poaceae, were collected in an olive grove. In the laboratory, leaves, particularly the interior part of the blade which is a common oviposition location for spittlebugs, were observed under binocular stereoscope. Viable eggs were introduced in petri dishes until hatching. A total of 647 egg-laying masses and 8,222 eggs with a mean of 12.7 eggs per egg laying was recorded. Egg masses were characterised and the action of predation, parasitism and fungi were recorded. Eggs presenting signs of parasitism plus predation were more than 50%. Intact field eggs were kept in controlled conditions until hatching of nymphs and evolution. The parasitoids were identified as Paracentrobia sp. (Trichogrammatidae) being the first report for the genus in Portugal. These results constitute an important opportunity to control the main insect vectors of X. fastidiosa and containing its spread. ; This work has received funding from the European Union's Horizon 2020 research and innovation programme underGrant Agreement N. 727987 'Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS'. ; info:eu-repo/semantics/publishedVersion

As the amount of debt has gradually increased, particularly in recent years, Portugal is currently one of the European countries exhibiting one of the highest levels of overall indebtedness, including in both sovereign and private sectors. Indeed, this condition is the outcome of increasing levels of debt assumed not only by the government, but also by companies and families, being the later mostly due to mortgage loans and due charges. This paper focuses on the study of borrowing by Portuguese households. The research has been made in respect to the notion of debt, the consequences of recent developments in debt, among other factors. In order to analyze the factors that are most associated with debt, a study was developed using two multiple regression models, one using a longer time series and another shorter, evaluating the effect of several variables, such as consumption, savings, unemployment, inflation and interest rates, in order to check whether they could be associated with a higher level of debt. ; This work is funded by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and by National Funds through FCT - Foundation for Science and Technology under the project with the reference PEst-C/CJP/UI4058/2011 ; info:eu-repo/semantics/publishedVersion

Table olives are a traditional component of the Mediterranean diet and are largely consumed in the world. There are different trade treatments that originate different types of olives. The aim of the present work was to proceed to the microbiological characterization of table olives commercialized in the Portuguese market, with respect to their microbiological safety. The microbiological characterization was made in the olive pulp and packing brine of thirty-five table olives samples of different types and trade treatments, namely natural olives Cv. Galega (NOG), natural turning colour olives (NTCO), green olives (GO), black ripe olives (BO) and natural olives purchased in the traditional market and obtained from traditional producers (NOt). Simultaneously it was verified specific legislation of the table olives in what it concerns to labeling rules, pH values and the identification of isolated yeasts. In general, table olives consumed showed acceptable security with exception of four NOt samples that presented Staphylococcus aureus. In a considerable number of samples high number of microorganisms indicators of contaminations were observed that reveals the need of optimization the hygienic procedures during production process to improve the quality and safety of table olives. During the work seven yeasts were isolated from olive pulp and brine.

Trioza erytreae, the African citrus psyllid, is a vector of Candidatus Liberibacter spp., the causal agent of the citrus greening disease or Huanglongbing (HLB). The spread of the vector throughout the Iberian Peninsula has been continuous since its introduction in mainland Spain in 2014. The patterns of host preference and feeding behaviour largely depend on olfactory cues. Understanding these patterns is crucial to prevent further dispersion and develop management measures against the pest. In this work, a series of settlement, olfactometric, probing, and feeding experiments were conducted to assess the host preference of T. erytreae for lemon or bitter orange plants. The settlement experiment provided evidence on the preference of both sexes of T. erytreae for lemon plants, whereas males did not show any significant choice pattern in the case of the olfactometric assays. Forty EPG variables were analysed to describe and compare the probing and feeding behaviour of T. erytreae on lemon and bitter orange plants. The EPG variables indicated that T. erytreae has some difficulties in accepting the phloem of bitter orange plants. This suggests that lemon plants would be a better source for the acquisition of Candidatus Liberibacter asiaticus (CLas) by T. erytreae since the psyllid spends much longer periods feeding from the phloem on lemon than on bitter orange. ; Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The authors are grateful to the European Union grant, programme H2020 entitled: PRE-HLB: Preventing HLB epidemics for ensuring citrus survival in Europe. H2020- SFS-2018–2 Topic SFS-05–2018-2019–2020—new and emerging risks to plant health (Project nº 817526) as well as to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020). ; info:eu-repo/semantics/publishedVersion

The olive fly, Bactrocera oleae (Rossi), a serious threat to the olive crop worldwide, displays ovipositon preference for some olive cultivars but the causes are still unclear. In the present work, three Portuguese olive cultivars with different susceptibilities to olive fly (Cobrançosa, Madural, and Verdeal Transmontana) were studied, aiming to determine if the olive volatiles are implicated in this interaction. Olive volatiles were assessed by SPME-GC-MS in the three cultivars during maturation process to observe possible correlations with olive fly infestation levels. Overall, 34 volatiles were identified in the olives, from 7 chemical classes (alcohols, aldehydes, aromatic hydrocarbons, esters, ketones, sesquiterpenes, and terpenes). Generally, total volatile amounts decrease during maturation but toluene, the main compound, increased in all cultivars, particularly in those with higher susceptibility to olive fly. Sesquiterpenes also raised, mainly α-copaene. Toluene and α-copaene, recognized oviposition promoters to olive fly, were correlated with the infestation level of cvs. Madural and Verdeal Trasnmontana (intermediate and highly susceptible cultivars respectively), while no correlations were established with cv. Cobrançosa (less susceptible). No volatiles with inverse correlation were observed. Volatile composition of olives may be a decisive factor in the olive fly choice to oviposit and this could be the basis for the development of new control strategies for this pest. ; This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through projects EXCL/AGR-PRO/0591/2012 "Olive crop protection in sustainable production under global climatic changes: linking ecological infrastructures to ecosystem functions" and Pest-C/EQB/LA0006/2013. Ricardo Malheiro thanks FCT, POPH-QREN (Programa Operacional Potencial Humano – Quadro de Referência Estratégico Nacional) and FSE (Fundo Social Europeu) for PhD grant (SFRH/BD/74675/2010). ; info:eu-repo/semantics/publishedVersion

The sterol compositions (GLC/FID/capillary column) of monovarietal olive oils (51 samples) from the most important cultivars of northeastern Portugal (Cvs. Cobranc¸osa, Madural and Verdeal Transmontana) and 27 commercial samples of olive oils with protected denomination of origin (PDO) from the same region and cultivars were evaluated. Δ-sitosterol, Δ5-avenasterol and campesterol were the most representative sterols. Cholesterol, stigmasterol, clerosterol and Δ7-stigmastenol were also found in all samples. All studied samples respected EC Regulation N. 2568, and in all cases total sterols were remarkably higher than the minimum limit set by legislation, ranging from 2003 to 2682 mg/kg. Results were analysed with the help of several statistical techniques, including reduction of dimensionality by principal component analysis with cross-validation of the number of components, followed by the use of canonical variate predictive biplots for model development and canonical variate interpolative biplots for approximate classification of monovarietal and PDO olive oils. These biplots proved to be a very interesting solution in the present case study, overcoming the problems of interpretation and classification that arise whenever different multivariate analyses are coupled together.