93 research outputs found
First record in Algeria of two eulophid wasps: Closterocerus chamaeleon (Girault) and its host, the eucalyptus gall wasp Ophelimus maskelli (Asmead) (Hymenoptera Eulophidae).
The endophagous parasitoid Closterocerus chamaeleon, released in Israel, Italy and Corsica, for classical biological control programs, and its host, the gall-maker Ophelimus maskelli, were recorded for the first time in Algeria, in a straight line 450 km far from the Sardinian release site and 700 km far from the closest Sicilian release site. Their presence is confirmed in Andalucia (Spain), about 2000 km far from release sites of Sicily and Campania. In about two years the parasitoid spread and was established in many Mediterranean countries
FACTORS AFFECTING THE INFESTATION DUE TO BACTROCERA OLEAE (ROSSI) IN SEVERAL SICILIAN OLIVE CULTIVARS
Contenimento naturale di Bactrocera oleae (Rossi): clima o parassitoidi? Confronto tra Western Cape (Sud Africa) e Sicilia
Bactrocera oleae (Rossi), mosca delle olive, e\u300 presente anche in Sud Africa, ma finora non si sono avute notizie di infestazioni economicamente rilevanti negli oliveti. L\u2019accertata presenza di un maggior numero di braconidi parassitoidi della mosca delle olive rispetto alle aree mediterranee e\u300 stata ed e\u300 considerata da molti autori la principale causa di queste minori infestazioni, senza che pero\u300 siano stati eseguiti in Sud Africa adeguati studi sulle infestazioni da B. oleae e sui fattori cli- matici delle aree interessate.
Analizzando recenti dati sui livelli d\u2019infestazione di B. oleae registrati su olivo coltivato e selvatico nel Western Cape e in Sicilia, appaiono simili in una normale annata fino a meta\u300 estate, ma sono nettamente differenti a fine estate-inizio autunno, quando in Sicilia il clima diviene piu\u300 umido. Da una puntuale analisi dei corrispondenti dati climatici registrati nelle due aree e\u300 infatti emersa una sostanziale differenza nel decorso piu\u300 caldo e secco degli ultimi tre mesi precedenti la raccolta nel Western Cape; questo periodo invece in Sicilia e\u300 caratterizzato da temperature piu\u300 fresche e un aumento dell\u2019umidita\u300 relativa che favorisce l\u2019impennata delle infestazioni di B. oleae. Nei quattro mesi presi in considerazione si rileva anche una significativa differenza nell\u2019escursione termica, maggiore nel Western Cape, dovuta a minime notturne piu\u300 basse.
Da un confronto dei livelli di parassitizzazione di B. oleae del Western Cape (Sud Africa) e dell\u2019area costiera della Provincia di Trapani, recentemente registrati su olivo colti- vato e selvatico (Olea europaea subsp. cuspidata in Sud Africa, Olea europaea subsp. europaea var. sylvestris in Sicilia) non sono emerse sostanziali differenze quantitative, pur confer- mando che in Sud Africa i principali parassitoidi sono tre bra- conidi (Utetes africanus (Sze\u301pligeti), Psyttalia lounsburyi (Silvestri) e Bracon celer (Sze\u301pligeti)), con il primo preva- lente sull\u2019olivo selvatico e l\u2019ultimo sul coltivato, mentre in Sicilia il braconide parassitoide Psyttalia concolor (Sze\u301pligeti) prevale sia sull\u2019olivo selvatico che sul coltivato. Comunque in entrambe le aree la parassitizzazione su B. oleae non rag- giunge elevati ed efficaci livelli.
Il clima, e non la parassitizzazione dovuta ai braconidi, appare il piu\u300 importante fattore di contenimento di B. oleae anche in Sud Africa.
L\u2019introduzione di parassitoidi specifici della mosca delle olive e\u300 necessaria nelle aree colonizzate di recente dove essi mancano, ma i tentativi di fornir loro una maggiore dis- ponibilita\u300 di larve dell\u2019ospite mediante l\u2019impianto di cultivar d\u2019olivo a maturazione e permanenza dei frutti piu\u300 differen- ziata, potrebbe produrre risultati certamente piu\u300 negativi che positivi nei confronti della presenza e dei livelli d\u2019infesta- zione di B. oleae sull\u2019olivo coltivato, come avviene nelle aree pandacie dove cresce spontaneo l\u2019olivastro.Natural environmental control of Bactrocera oleae (Rossi): climate or parasitoids? A comparison between the Western Cape of South Africa and Sicily.
Bactrocera oleae (Rossi), the olive fruit fly is considered not a continuosly serious pest of olive trees in the Western Cape of South Africa, in spite of the climate similar to Mediterranean areas. South African braconid parasitoids of B. oleae are more numerous than in Mediterranean areas, and until now their action has been considered the factor lowering the level of infestation due to the olive fruit fly, but no deep studies on its infestation levels and climatic factors influencing them were carried out in the past. Analyzing recent data on infestation levels collected in the Western Cape and Sicily, they appear similar in a regular mid- summer, differing at the end of summer-beginning of autumn, when in Sicily the climate becomes more humid than in the Western Cape. A comparison of climatic data regarding four years underlines that Somerset West and Franshhoek, in comparison with Trapani, have significantly lower minimum daily temperatures, a higher daily thermal excursion and a lower relative humidity in the last three months preceding harvesting.
Parasitization rates on B. oleae of Western Cape and Sicily, recorded on both cultivated and wild olives (Olea europaea subsp. cuspidata in South Africa, Olea europaea subsp. europaea var. sylvestris in Sicily) are not substantially different, confirming that in South Africa three braconids, Utetes africanus (Sze\u301pligeti), Psyttalia lounsburyi (Silvestri) and Bracon celer (Sze\u301pligeti), are the main parasitoids, with the first one as leader in wild olives and the last one as leader in cultivated ones, while in Sicily the braconid Psyttalia concolor (Sze\u301pligeti) is the main parasitoid in both wild and cultivated olives. Nevertheless parasitism on B. oleae doesn\u2019t reach effective levels of control in bats ragions.
The climate, instead of parasitization due to braconids, is the main environmental factor limiting the olive fruit fly infestations in the Western Cape of South Africa.
The introduction of parasitoids specific to the olive fruit fly is necessary in new invaded areas where they lack, but the attempt of providing them a more available amount of host fruits along the year, planting olive trees bearing fruits up to spring, could bring serious problems as those typical of Mediterranean areas where the European wild olive naturally grows
Wild olive seed weevil, Anchonocranus oleae Marshall (Coleoptera: Curculionidae), in cultivated olives in South Africa
Wild olive seed weevil, Anchonocranus oleae Marshall, larvae as well as oviposition and feeding damage were recorded in cultivated olives during a recent study on olive seed wasps in South Africa. Prematurely dropped fruit and fruit picked at harvest in two orchards near Stellenbosch and Agter- Paarl were examined regularly for olive seed wasp infestation over three seasons. In addition, olives were collected over a wider area of the olive growing regions of the Western Cape province for a survey to determine olive seed wasp distribution. DNA barcoding confirmed the identity of weevil larvae in kernels as A. oleae. The number of A. oleae larvae found in olive seeds and the number of olives with weevil oviposition or feeding damage were low. The presence of larvae and weevil damage in two orchards in the survey with no wild olive trees in close proximity suggest that the weevil could breed and persist in cultivated olive orchards. Currently A. oleae is not of economic concern, but if infested olives are discarded at harvest and left in orchards, the weevils could complete their development in the kernels and numbers could increase to damaging levels
Influence of distance from the host on parasitisation by Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae)
The olive fruit fly, Bactrocera oleae, is considered the main olive pest worldwide, and has been the target of biological control programmes through the release of the braconid parasitoid Psyttalia concolor. Laboratory tests were performed to evaluate the influence of distance from the host on parasitisation, placing larvae of the substitute host Ceratitis capitata at seven distances (0, 0.5, 1, 1.5, 2, 2.5, 3 mm) and four different time periods (7, 15, 30, 60 min). Moreover, field collected olives of Ogliarola Barese cultivar infested by B. oleae were exposed to P. concolor females to confirm its ability to parasitise B. oleae in small olives. Psyttalia concolor oviposition was inhibited at 2.5 and 3 mm due to the ovipositor length of the parasitoid females (2.7 mm). Hosts were easily parasitised at distances between 0 and 1.5 mm. The thin fruit pulp (up to 3.5 mm) of field collected olives allowed the parasitisation to occur also in mature fruits. At the best combination distance/time (0 mm, 30 min), tests performed with different larvae/parasitoid female ratio showed an increasing emergence of P. concolor (from 20% to 57%) with larvae/parasitoid ratio increasing from 0.11 to 0.74. The results of the present study might optimise the mass rearing of P. concolor, through a proper setting of its parameters, such as the host/parasitoid ratio, exposure distances, and interaction time
Mitogenomics of the Olive Seed Weevil, Anchonocranus oleae Marshall and Implications for Its Phylogenetic Position in Curculionidae
Anchonocranus oleae Marshall (Coleoptera: Curculionidae) is a seed-feeding weevil native to southern Africa; its larvae are known to develop in the fruits of the African Wild Olive and, more rarely, cultivated olives. The species has been mainly found in the Western Cape province of South Africa, but it has remained in relative obscurity because it does not seem to represent a current threat to commercial olive production. As part of an ongoing effort to produce baseline genetic data for olive-associated entomofauna in South Africa, we generated reference DNA barcodes for A. oleae collected from wild and cultivated olives and sequenced its mitogenome for assessment of the phylogenetic position of the species in the family Curculionidae. The mitochondrial phylogeny estimate indicated that A. oleae shares a common ancestor with Elaidobius (tribe Derelomini), but a definite and close relationship to this tribe and the precise tribal placement of A. oleae in the subfamily Curculioninae could not be inferred due to the lack of representative mitogenomes of other relevant curculionine tribes and genera. This study will assist future work on the DNA-based species identification, genetic diversity, and phylogenetic position of the genus Anchonocranus and related taxa
A methodological approach of QRA for slow-moving landslides at a regional scale
Landslides represent a serious worldwide hazard, especially in Italy, where exposure to hydrogeological risk is very high; for this reason, a landslide quantitative risk assessment (QRA) is crucial for risk management and for planning mitigation measures. In this study, we present and describe a novel methodological approach of QRA for slow-moving landslides, aiming at national replicability. This procedure has been applied at the basin scale in the Arno River basin (9100 km(2), Central Italy), where most landslides are slow-moving. QRA is based on the application of the equation risk = hazard (H) × vulnerability (V) × exposure (E) and on the use of open data with uniform characteristics at the national scale. The study area was divided into a grid with a 1 km(2) cell size, and for each cell, the parameters necessary for the risk assessment were calculated. The obtained results show that the total risk of the study area amounts to approximately 7 billion €. The proposed methodology presents several novelties in the risk assessment for the regional/national scale of the analysis, mainly concerning the identification of the datasets and the development of new methodologies that could be applicable over such large areas. The present work demonstrates the feasibility of the methodology and discusses the obtained results
A morphological, biological and molecular approach reveals four cryptic species of Trissolcus Ashmead (Hymenoptera, Scelionidae), egg parasitoids of Pentatomidae (Hemiptera)
Accurate identification of parasitoids is crucial for biological control of the invasive brown marmorated stink bug, Halyomrpha halys (Stål). A recent work by Talamas et al. (2017) revised the Palearctic fauna of Trissolcus Ashmead, egg-parasitoids of stink bugs, and treated numerous species as junior synonyms of T. semistriatus (Nees von Esenbeck). In the present paper, we provide a detailed taxonomic history and treatment of T. semistriatus and the species treated as its synonyms by Talamas et al. (2017) based on examination of primary types, molecular analyses and mating experiments. Trissolcus semistriatus, T. belenus (Walker), T. colemani (Crawford), and T. manteroi (Kieffer) are here recognized as valid and a key to species is provided. The identification tools provided here will facilitate the use of Trissolcus wasps as biological control agents and as the subject of ecological studies
Characterization of an Italian founder mutation in the RING-finger domain of BRCA1
The identification of founder mutations in cancer predisposing genes is important to improve risk assessment in geographically defined populations, since it may provide specific targets resulting in cost-effective genetic testing. Here, we report the characterization of the BRCA1 c.190T>C (p.Cys64Arg) mutation, mapped to the RING-finger domain coding region, that we detected in 43 hereditary breast/ovarian cancer (HBOC) families, for the large part originating from the province of Bergamo (Northern Italy). Haplotype analysis was performed in 21 families, and led to the identification of a shared haplotype extending over three BRCA1-associated marker loci (0.4 cM). Using the DMLE+2.2 software program and regional population demographic data, we were able to estimate the age of the mutation to vary between 3,100 and 3,350 years old. Functional characterization of the mutation was carried out at both transcript and protein level. Reverse transcriptase-PCR analysis on lymphoblastoid cells revealed expression of full length mRNA from the mutant allele. A green fluorescent protein (GFP)-fragment reassembly assay showed that the p.Cys64Arg substitution prevents the binding of the BRCA1 protein to the interacting protein BARD1, in a similar way as proven deleterious mutations in the RING-domain. Overall, 55 of 83 (66%) female mutation carriers had a diagnosis of breast and/or ovarian cancer. Our observations indicate that the BRCA1 c.190T>C is a pathogenic founder mutation present in the Italian population. Further analyses will evaluate whether screening for this mutation can be suggested as an effective strategy for the rapid identification of at-risk individuals in the Bergamo area
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