1,720,962 research outputs found
Diversity of aphids (Hemiptera: Aphidomorpha) landing on nectarine trees in the orchards in Serbia
No full textSeveral aphid species (Hemiptera: Aphididae) can cause direct feeding damage to nectarines. Many winged aphid species fly over from other plants, making short feeding trials on nectarine in search of a host plant. Some of them play an important role in the transmission of plant viruses and cause indirect damage to this plant. This study aimed to evaluate the diversity of aphids landing on nectarine trees, with particular reference to the species described in the literature as known vectors of Plum Pox Virus (PPV). The study was conducted in important nectarine growing areas in Serbia, at Topola and Sr. Mitrovica sites, during the three-year study (2020–2022). The sticky shoot method was used to capture winged aphids that landed on the nectarine leaves during the growing season. Every 10–15 days, two shoots on five randomly selected trees were sprayed with glue. The aphids from the shoots were treated with turpentine and soapy water and preserved in 70% ethanol. Aphids were identified morphologically and molecularly through PCR techniques. During the study, 388 aphid specimens were collected (286 in Topola and 102 in Sr. Mitrovica). The highest total number of aphids was caught in 2020 (309). In the two following years, a much lower number of aphids was recorded (18 in 2021 and 61 in 2022). Aphid population dynamics fluctuated greatly during the growing season. Maximum population density of aphids and maximum potential vector activity were detected in May–June at both sites in all three years. The highest density (5.2 specimens per shoot) was detected at the Topola site on 10th May 2020. The collected specimens were classified into 43 different taxa. The most abundant species belong to the genera Aphis, Rhopalosiphum, and Therioaphis. One of the most abundant species at the Topola sites was Viteus vitifoliae (Phylloxeridae). The identification of this species was confirmed by molecular techniques. Several species collected in this study (Aphis craccivora, A. fabae, A. gossypii, A. pomi/spiraecola, Hyalopterus pruni, Macrosiphum rosae, Myzus persicae, Phorodon humuli, Rhopalosiphum maidis, R. padi) are potential vectors of PPV. The proportion of known PPV vectors in the total number of detected aphids on nectarine was 8.03, 33.33 and 20.75% in Topola, and 17.60, 33.33, and 50% in Sr. Mitorvica in 2020, 2021 and 2022, respectively
The quiet spread of Aleurocanthus spiniferus (Quaintance, 1903) (Hemiptera, Aleyrodidae) in Europe
No full textAfter its first discovery in Europe, in Apulia (Italy) in 2008, the citrus spiny whitefly (CSW), Aleurocanthus spiniferus (Quaintance, 1903) (Hemiptera Aleyrodidae) spread throughout the Italian peninsula, as well as in Albania, Bulgaria, Croatia, Greece and Montenegro. The species has been established mainly in urban areas, infesting ornamental plants in public and private gardens. Recently, CSW is also infesting some important cultivated plants. In Apulia, increasingly intense infestations are reported on grapevines, while in Basilicata, Calabria, Sicily as well as Apulia, the pest is present in commercial groves of Citrus × sinensis. The CSW is a polyphagous species, easily adaptable to various environmental conditions. For example, in 2022, the pest was found in a greenhouse in Holland, showing its potential to spread throughout Europe. The main pathway is transportation with infested plant material. From 2021, the diffusion, biology and natural enemies of A. spiniferus in Sicilian citrus cultivation areas were investigated through field surveys carried out by direct plant sampling and yellow sticky traps. First observations showed that the pest developed three generations in 2022. The adults of the first generation emerged from the overwintering nymphs in late March, while a second generation followed in late June–early July. The third generation occurred in the middle of October. The presence of the adults lasted for a period ranging from one to almost two months. In one case, overlapping generations were observed, as adults were recorded throughout the period from April to October. Several natural enemies were collected, such as Zelus renardii (Kolenati) (Hemiptera, Reduviidae) and Campyloneura virgula (Herrich-Schaeffer) (Hemiptera, Miridae). The most interesting species in terms of its abundance and activity was Serangium montazerii Fürsch (Coleoptera, Coccinellidae), a predator recorded for the first time in Italy and known as a specific natural antagonist of whiteflies. Studies are underway concerning the development of bio-molecular diagnostic methodologies for a rapid identification of A. spiniferus in areas where it has been found as well as for the detection of new outbreaks. These systems support morphological identification and would guarantee a timely genetic identification of the species
Reptalus quinquecostatus (Dufour, 1833) (Fulgoromorpha: Cixiidae) plant preferences in Serbia
No full textReptalus quinquecostatus (Dufour, 1833) is one of several species from the planthopper family Cixiidae that are known as vectors of plant pathogenic bacteria that can cause severe agroeconomic losses. Records of this species in Serbia by Horváth, Tanasijević and Janković refer to Oliarus quinquecostatus Dufour, 1883 [sic]. The species was described as inhabiting meadows and grasslands and reported as caught on Salix sp., Ulmus sp., Quercus sp., and Malva sylvestris. Modern-day molecular identification of species, i.e. sequencing of cytochrome oxidase subunit 1 (COI) gene, revealed the presence of R. quinquecostatus nymphs in the rhizosphere of Koeleria macrantha (Poaceae family) in eastern Serbia. This cixiid has been found in Serbia on various crops affected by ‘Candidatus Phytoplasma solani’: corn, grapevine, potato, and most recently, sugar beet. The occurrence on sugar beet was first reported in 2020 in northern Serbia when its population was aggregated on a boundary strip with several weeds: Convolvulus arvensis, Chenopodium album, Amaranthus retroflexus, Ambrosia artemisiifolia etc. During the 2021–2022 survey, the presence of R. quinquecostatus on sugar beet was confirmed on other localities in Serbia. Moreover, its populations were recorded on parsnip, tobacco and corn. Prunus spinosa and Crataegus sp. in microhabitats permeating arable land were also found preferable for R. quinquecostatus adults. Its several populations on different hosts were repeatedly sampled in June–July 2022. Populations on P. spinosa and Crataegus sp. were highly abundant and infected with ‘Ca. P. solani’, whereas in the agroecosystems, R. quinquecostatus is present in mixed population with R. panzeri, displaying minor precedence in the emergence of adults. Data on R. quinquecostatus plant preferences in Serbia support the polyphagy that has been previously reported throughout Europe. Since the genus Reptalus Emeljanov, 1971 has recently undergone nomenclatural and taxonomic revision, the use of the valid species name and proper morphological species identification, which in some cases should be supplemented with molecular tools, are crucial in biodiversity and insect pest research
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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