1,720,963 research outputs found
New strategies to control brown rot caused by Monilinia spp. of stone fruit
No full textThe importance of brown rot caused by Monilinia spp. in all stone fruit growing areas is well recognized. The infection occurs in the field but the most dangerous fruit losses happen during storage and commercialization. The disease control depends mainly on integrated strategy based on cultural practices and fungicide spray programmes in the field. Among cultural practices, the sanitization of orchard by minimizing inoculum potential, reducing the risk of blossom and fruit infections is essential for brown rot management. However, the requirements in sustainable agriculture, integrated crop management and organic production are increased in the last few decades, resulting in the need to develop other methods than fungicide applications to disease control. Several studies focused on alternative strategies, defining three different approaches: i) biological control with microbial antagonists, ii) use of natural products and iii) use of physico-chemical methods. Significant progress has been achieved in the reduction of pesticide use with these methods; although a multidisciplinary methodology that integrates sanitary and alternative strategies has to be investigated more fully. The new strategy, starting from the field with agronomic interventions and the selection of cultivars tolerant to Monilinia spp. could be usefully integrated by postharvest treatments based on low risk chemical fungicides, natural antimicrobial substances and other physical means determining a sustainable approach to brown rot control
First Report of Apple Bull’s Eye Rot Caused by Neofabraea malicorticis in Italy
No full textBull’s eye rot is an important postharvest disease affecting apples (Malus domestica)
worldwide. Fruit infection occurs in the field, but rot lesions develop only after a period in cold
storage (about 90 days). The disease is caused by fungi belonging to genus Neofabraea (N.
vagabunda, N. malicorticis, N. perennans, and N. kienholzii) (Spotts et al. 2009). However, no
data are available on the presence of species other than N. vagabunda in Italy. To verify the
current causal agents of apple bull’s eye rot in the Emilia-Romagna region, a pathogen survey
of apples stored in several local packinghouses and showing bull’s eye rot symptoms was
carried out in 2014 and the causative agents identified. Small sections from the edges of
rotten tissue of 100 fruits were placed on tomato agar (TA) and kept at 15°C. Sporulation was
observed after 14 days of incubation. Mycelia originated from the single spore of 20 isolates
were used for DNA extraction. PCR was used to amplify the β-tubulin (tub2) gene using
primers F 5′-CTTTCTCCGTTGTCCCATCC-3′ and R 5′-GAACATTGCGCATCTGGTCC-3′ (Cao et al.
2013). After sequencing and sequence assembly, BLAST analysis showed that one isolate (M1)
had 99% identity to N. malicorticis, while other isolates belonged to N. vagabunda. The
sequence of N. malicorticis isolate was submitted to GenBank (accession no. KP263368).
Morphological characteristics of N. malicorticis isolate were examined after 14 days of
incubation on TA at 15°C. Colonies were circular, centrally umbonate, with abundant white
floccose mycelium. Average growth rate was 22 ± 2 mm in 14 days. Conidia were one-celled,
cylindrical, rounded at apex, aseptate, hyaline, and measured 6 to 16 μm (mean 10 ± 2.4 μm)
× 2 to 5 μm (mean 3 ± 0.8 μm), similar to micro and intermediate conidia formed on oatmeal
(Chen et al. 2015). To prove pathogenicity, Koch’s postulates were conducted on 10 ‘Cripps
Pink’ apples, surface-sterilized, wounded, and inoculated with 20 μl conidial suspension (104
conidia ml–1). After 90 days of storage at 0°C, artificially infected apples showed lesions of 21
to 29 ± 1 mm diameter without conidiomata on peel surface (symptoms identical to those
observed on apples that were originally obtained from cold storage). Water-only controls were
symptomless. The pathogen was reisolated from decayed tissue. To our knowledge, this is the
first report of N. malicorticis causing bull’s eye rot of apples in Italy. This finding suggests that,
beside N. vagabunda, other species of Neofabraea may occur in Italy and this could represent
an emerging problem on apples. Epidemiological studies performed on a wider scale could
improve the knowledge of current Neofabraea species occurring in Italian orchards, leading to
the adoption of specific control strategies to reduce fruit postharvest losses
New Strategies to Control Brown Rot Caused by Monilinia spp. of Stone Fruit
Full text linkThe importance of brown rot caused by Monilinia spp. in all stone fruit growing areas is well recognized. The infection occurs in the field but the most dangerous fruit losses happen during storage and commercialization. The disease control depends mainly on integrated strategy based on cultural practices and fungicide spray programmes in the field. Among cultural practices, the sanitization of orchard by minimizing inoculum potential, reducing the risk of blossom and fruit infections is essential for brown rot management. However, the requirements in sustainable agriculture, integrated crop management and organic production are increased in the last few decades, resulting in the need to develop other methods than fungicide applications to disease control. Several studies focused on alternative strategies, defining three different approaches: i) biological control with microbial antagonists, ii) use of natural products and iii) use of physico-chemical methods. Significant progress has been achieved in the reduction of pesticide use with these methods; although a multidisciplinary methodology that integrates sanitary and alternative strategies has to be investigated more fully. The new strategy, starting from the field with agronomic interventions and the selection of cultivars tolerant to Monilinia spp. could be usefully integrated by postharvest treatments based on low risk chemical fungicides, natural antimicrobial substances and other physical means determining a sustainable approach to brown rot control
Influence of harvest date on Bull's eye rot of 'Cripps Pink' apple and control chemical strategies
No full textThe influence of four different harvest times on the bull’s eye rot of
‘Cripps Pink’ apple caused by Neofabraea spp. was investigated in
two orchards harvested at four different times. In addition, a control
strategy based on chemical treatments performed in preharvest or postharvest
was evaluated. Regression analysis between harvest time and
disease incidence revealed high r2 values (>0.75). All preharvest
fungicide treatments significantly (P < 0.0085) reduced the bull’s
eye rot incidence; however, thiophanate-methyl (achieving >87% control)
was more effective than a mixture of pyraclostrobin and boscalid
(<80.7%) or fludioxonil (<57.6%), in all trials. Compared with nontreated
control fruit, a postharvest treatment with the ethylene inhibitor
1-methylcyclopropene (1-MCP) halved the incidence of infection in
three of four experiments. However, a combination of two preharvest
treatments with a mixture of pyraclostrobin plus boscalid and one postharvest
1-MPC treatment suppressed bull’s eye rot to a significantly
(P < 0.00001) greater degree (achieving >87.5% control) than the single
treatments with pyraclostrobin and boscalid (<65%) and 1-MCP
(<80%) tested alone
Effect of apple cultivars and storage periods on the virulence of Neofabraea spp.
No full textBull’s eye rot is a typical quiescent postharvest apple disease in major fruit‐growing areas. The susceptibility of different apple cultivars to Neofabraea spp. (N. vagabunda and N. malicorticis) was assessed, with Granny Smith showing the most resistance and Cripps Pink the most susceptibility. To assess the factors involved in conidial germination, Neofabraea spp. were grown on crude protein extracts (CPEs) collected from apple fruits at different storage periods. Fungal germ tube growth rate and pathogenic enzyme (cellulase and xylanase) activity were assessed. Results showed that CPEs collected after 2 and 4 months of storage progressively stimulated conidial germination and germ tube elongation, while a lesser effect was observed from CPEs after 1 month of storage. Xylanase proved to be the main degrading enzyme secreted by all the isolates, while cellulase was produced only by N. vagabunda isolates. Overall, the isolate ID02 was the most virulent, based on more rapid germ tube elongation and greater activity of the lytic enzymes
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
Apple latent infection caused by Neofabraea alba: host-pathogen interaction and disease management
No full textApple latent infection caused by Neofabraea alba: host-pathogen interaction and disease management
Bull’s eye rot (BER) caused by Neofabraea alba is one of the most frequent and damaging latent infection occurring in stored pome fruits worldwide. Fruit infection occurs in the orchard, but disease symptoms appear only 3 months after harvest, during refrigerated storage. In Italy BER is particularly serious for late harvest apple cultivar as ‘Pink Lady™’. The purposes of this thesis were: i) Evaluate the influence of ‘Pink Lady™’ apple primary metabolites in N. alba quiescence ii) Evaluate the influence of pH in five different apple cultivars on BER susceptibility iii) To find out not chemical method to control N. alba infection iv) Identify some fungal volatile compounds in order to use them as N. alba infections markers. Results regarding the role of primary metabolites showed that chlorogenic, quinic and malic acid inhibit N. alba development. The study based on the evaluation of cultivar susceptibility, showed that Granny Smith was the most resistant apple cultivar among the varieties analyzed. Moreover, Granny Smith showed the lowest pH value from harvest until the end of storage, supporting the thesis that ambient pH could be involved in the interaction between N. alba and apple. In order to find out new technologies able to improve lenticel rot management, the application of a non-destructive device for the determination of chlorophyll content was applied. Results showed that fruit with higher chlorophyll content are less susceptible to BER, and molecular analyses comforted this result. Fruits with higher chlorophyll content showed up-regulation of PGIP and HCT, genes involved in plant defence. Through the application of PTR-MS and SPME GC-MS, 25 volatile organic compounds emitted by N. alba were identified. Among them, 16 molecules were identified as potential biomarkers
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