scholarly journals Inoculum and Infection Dynamics of Polystigma amygdalinum in Almond Orchards in Spain

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1239-1246
Author(s):  
Erick Zúñiga ◽  
Joaquín Romero ◽  
Andrés Ollero-Lara ◽  
María Lovera ◽  
Octavio Arquero ◽  
...  
Keyword(s):  
Geographical Location ◽  
Sampling Period ◽  
Seasonal Development ◽  
Leaf Blotch ◽  
Infection Dynamics ◽  
Ascospore Germination ◽  
Severe Infections ◽  
Almond Orchards ◽  
Key Aspects ◽  
The Mediterranean Basin

Red leaf blotch (RLB) disease of almond, caused by Polystigma amygdalinum, is an important foliar disease in most production regions of the Mediterranean basin and the Middle East because severe infections may cause a premature defoliation of the tree. Some key aspects on the epidemiology of P. amygdalinum were studied in multiyear trials in two almond-growing regions in Spain, which included the seasonal development of perithecia and production and germination of ascospores along with the disease incubation and plant infectivity periods. Our results showed that primary inoculum was available in extended periods (January to August). Significant differences in ascospore amounts among regions, higher in the southern Andalusia and lower in the northern Catalonia, and years of study were detected. The factors geographical location, sampling period, and evaluation year were found significant on the development of P. amygdalinum perithecia. Variable ascospore germination rates were observed from April to July: >15% but rarely exceeding 30%. The RLB infectivity period in Catalonia extended from March to mid-June, whereas in Andalusia it was from March to May. The incubation period was mainly in a range of 5 to 10 weeks in Catalonia. The environmental conditions of October to January influence the available ascospore amounts in the next season. RLB infection occurs in spring to summer when mean temperatures are in the range 10 to 20°C. These results represent the first step in developing a prediction model of the disease that might serve as a tool for the control of RLB.

scholarly journals Seasonal Changes and the Interaction Between the Horse Chestnut Leaf Miner Cameraria ohridella and the Horse Chestnut Leaf Blotch Guignardia aesculi

2021 ◽  
Author(s):  
Michal Kopačka ◽  
Gösta Nachman ◽  
Rostislav Zemek
Keyword(s):  
Sampling Site ◽  
Sampling Period ◽  
Leaf Damage ◽  
Leaf Miner ◽  
Invasive Pest ◽  
Horse Chestnut ◽  
Leaf Blotch ◽  
Chestnut Leaf ◽  
The Mathematical Model ◽  
The Relationship

The horse chestnut leaf miner Cameraria ohridella (Lepidoptera: Gracillariidae) is an invasive pest of horse chestnut and has spread through Europe since 1985. The horse chestnut leaf blotch Guignardia aesculi (Botryosphaeriales: Botryosphaeriaceae) is a fungal disease that also seriously damages horse chestnut trees in Europe. The interaction between the leaf miner and the fungus has not yet been sufficiently described. Therefore, the aim of the present study was to assess leaf damage inflicted to horse chestnut by both C. ohridella and G. aesculi during the vegetation season and to model their interaction. The damage to leaf area was measured monthly from May to September 2013 in České Budějovice, the Czech Republic. A simple phenomenological model describing the expected dynamics of the two species was developed. The study revealed a significant effect of sampling site and sampling period on the damage caused by both the pest and the fungus. The mathematical model indicates that infestation by C. ohridella is more affected by G. aesculi than vice versa. The possible mechanisms affecting the relationship between G. aesculi and C. ohridella are discussed.

scholarly journals Local brucellosis outbreak on Thassos, Greece: a preliminary report

2008 ◽  
Vol 13 (25) ◽  
Author(s):  
R Vorou ◽  
K Gkolfinopoulou ◽  
G Dougas ◽  
K Mellou ◽  
IN Pierroutsakos ◽  
...  
Keyword(s):  
Infected Animal ◽  
Case Fatality ◽  
Human Brucellosis ◽  
Southeastern Europe ◽  
Animal Tissues ◽  
Death Case ◽  
Insidious Onset ◽  
Severe Infections ◽  
The Central Nervous System ◽  
The Mediterranean Basin

Brucellosis is a zoonosis resulting in reproductive failure in wild and domestic animals and febrile disease and occasionally severe infections of the central nervous system and endocarditis in humans. In animals and humans alike, it is found worldwide, including southeastern Europe, the Mediterranean basin (Portugal, Spain, southern France, Italy, Greece, Turkey, northern Africa), parts of Mexico, Central and Latin America, Asia, and Africa [1]. Human brucellosis represents a professional hazard, being acquired via ingestion, inhalation in laboratories or abattoirs, conjunctiva and skin trauma contamination with infected animal tissues and products [1,2]. Symptoms can appear as acute or insidious onset, after five to 60 days and last for days, months and occasionally as long as a year. Relapses can also occur. Treatment is effective with antibiotics. Untreated brucellosis can lead to death (case-fatality ratio around 2%), usually by heart complications.

Influence of ethical behaviors in corporate governance

2015 ◽  
Vol 8 (3) ◽  
pp. 586-611 ◽  
Author(s):  
Eduardo V. Lopez ◽  
Alicia Medina
Keyword(s):  
Corporate Governance ◽  
Lived Experience ◽  
Critical Realism ◽  
Geographical Location ◽  
Content Type ◽  
Ethical Behaviors ◽  
Unethical Behaviors ◽  
The Usa ◽  
Key Aspects ◽  
Practical Implications

Purpose – The purpose of this paper is to provide a summary of key aspects of a recently defended PhD thesis. It enables readers who may be interested in the thesis topic to gain an overview of that work and a link to the entire thesis through a URL link www.dropbox.com/s/1gikjlh6qw0v26u/Dissertation_Eduardo_Lopez_03122015.pdf?dl=0. The second purpose of this Thesis Research Note (TRN) is to explain the thesis author’s doctoral journey. Design/methodology/approach – The methodology was rooted in critical realism using mixed research methods. The approach for the paper is to provide a reflective narrative to explain the lived experience of the authors throughout the candidate’s doctoral journey. Findings – The theoretical implications of this study are the introduction of two new constructs (The Small Sins Allowed (SSA) and the Line of Impunity (LoI)) and the definition of these constructs as variables that affect corporate governance. Research limitations/implications – Although this study was intended to collect feedback regardless of geographical location, over 91 percent of responses came from the USA, Canada, and Latin America. For this reason, generalization beyond these boundaries requires further analysis. Practical implications – The practical implications are related to the application of the two constructs (SSA and the LoI) into the daily corporate governance activities. Social implications – SSA and LoI, can be the foundation for renewed and vigorous corporate governance. SSA helps to establish a level above which adherence to ethical standards is expected. LoI aids in identifying ethical fault lines. Together they help to keep unethical behaviors under control. Originality/value – The TRN provides a highly individualized account of a doctoral journey but it is intended to contribute to the growing body of TRNs published in this journal that in turn may inform decisions relating to candidates embarking on a doctoral journey.

scholarly journals Environmental reservoir dynamics predict global infection patterns and population impacts for the fungal disease white-nose syndrome

2020 ◽  
Vol 117 (13) ◽  
pp. 7255-7262 ◽  
Author(s):  
Joseph R. Hoyt ◽  
Kate E. Langwig ◽  
Keping Sun ◽  
Katy L. Parise ◽  
Aoqiang Li ◽  
...  
Keyword(s):  
Disease Outbreaks ◽  
Population Declines ◽  
Pseudogymnoascus Destructans ◽  
White Nose Syndrome ◽  
Infection Dynamics ◽  
Environmental Reservoir ◽  
Severe Infections ◽  
Seasonal Epidemics ◽  
Host Infection ◽  
The Impact

Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of P. destructans in the environment altered infection patterns in bats and influenced whether host populations were stable or experienced severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.

scholarly journals Dissecting the determinants of malaria chronicity: why within-host models struggle to reproduce infection dynamics

2015 ◽  
Vol 12 (104) ◽  
pp. 20141379 ◽  
Author(s):  
Lauren M. Childs ◽  
Caroline O. Buckee
Keyword(s):  
Host Immune System ◽  
Chronic Infections ◽  
Malaria Epidemiology ◽  
Infection Dynamics ◽  
Duration Of Infection ◽  
Severe Infections ◽  
And Control ◽  
The Impact ◽  
Do So ◽  
Parasite Dynamics

The duration of infection is fundamental to the epidemiological behaviour of any infectious disease, but remains one of the most poorly understood aspects of malaria. In endemic areas, the malaria parasite Plasmodium falciparum can cause both acute, severe infections and asymptomatic, chronic infections through its interaction with the host immune system. Frequent superinfection and massive parasite genetic diversity make it extremely difficult to accurately measure the distribution of infection lengths, complicating the estimation of basic epidemiological parameters and the prediction of the impact of interventions. Mathematical models have qualitatively reproduced parasite dynamics early during infection, but reproducing long-lived chronic infections remains much more challenging. Here, we construct a model of infection dynamics to examine the consequences of common biological assumptions for the generation of chronicity and the impact of co-infection. We find that although a combination of host and parasite heterogeneities are capable of generating chronic infections, they do so only under restricted parameter choices. Furthermore, under biologically plausible assumptions, co-infection of parasite genotypes can alter the course of infection of both the resident and co-infecting strain in complex non-intuitive ways. We outline the most important puzzles for within-host models of malaria arising from our analysis, and their implications for malaria epidemiology and control.

scholarly journals Determining the hierarchical order by which the variables of sampling season, dust outbreaks occurrence, and sampling location, can shape the airborne bacterial communities in the Mediterranean basin

2020 ◽  
Author(s):  
Riccardo Rosselli ◽  
Maura Fiamma ◽  
Massimo Deligios ◽  
Gabriella Pintus ◽  
Grazia Pellizzaro ◽  
...  
Keyword(s):  
Community Composition ◽  
Bacterial Communities ◽  
Mediterranean Basin ◽  
Sampling Period ◽  
Sampling Location ◽  
The Mediterranean ◽  
Wind Regimes ◽  
The One ◽  
The Mediterranean Basin ◽  
Community Evenness

Abstract. An NGS-based taxonomic analysis was carried out on airborne bacteria sampled at ground level in two periods (May and September) and two opposite localities on the North-South axis of the Sardinia Island. Located in a central position of the Mediterranean basin, Sardinia constitutes a suitable outpost to reveal possible immigration of bacterial taxa during transcontinental particle discharge between Africa and Europe. With the aim of verifying relative effects of dust outbreaks, sampling period and sampling site, on the airborne bacterial community composition, we compared air collected during dust-carrying meteorological events to that coming from wind regimes not associated to long-distance particle lifting. Results indicated that: (a) a higher microbial diversity (118 orders vs 65) and increased community evenness were observed in the campaign carried out in September in comparison to the one in May, irrespective of the place of collection and of the presence or absence of dust outbreaks. (b) During the period of standard wind regimes without transcontinental outbreaks a synchronous, concerted succession of bacterial communities across distant locations of the same island, accompanied as mentioned by a parallel rise in bacterial diversity and community evenness appears to have occurred. (c) changes in wind provenance could transiently change community composition in the locality placed on the coast facing the incoming wind, but not in the one located at the opposite side of the island; for this reason the community changes brought from dust outbreaks of African origin are observed only in the sampling station exposed to south; (d) the same winds, once proceeding over land appear to uplift bacteria belonging to a common core already present over the region, which dilute or replace those that were associated with the air coming from the sea or conveyed by the dust particulate, explaining the two prior points. (e) the hierarchy of the variables tested in determining bacterial assemblages composition results: sampling period >> ongoing meteorological events > sampling location within the island.

scholarly journals Determining the hierarchical order by which the variables of sampling period, dust outbreak occurrence, and sampling location can shape the airborne bacterial communities in the Mediterranean basin

2021 ◽  
Vol 18 (14) ◽  
pp. 4351-4367
Author(s):  
Riccardo Rosselli ◽  
Maura Fiamma ◽  
Massimo Deligios ◽  
Gabriella Pintus ◽  
Grazia Pellizzaro ◽  
...  
Keyword(s):  
Community Composition ◽  
Bacterial Communities ◽  
Mediterranean Basin ◽  
Sampling Period ◽  
Sampling Location ◽  
The Mediterranean ◽  
Wind Regimes ◽  
The One ◽  
The Mediterranean Basin ◽  
Community Evenness

Abstract. A next-generation sequencing (NGS)-based taxonomic analysis was carried out on airborne bacteria sampled at ground level in two periods (May and September) and two opposite locations on the north–south axis of the island of Sardinia. Located in a central position of the Mediterranean basin, Sardinia constitutes a suitable outpost for revealing possible immigration of bacterial taxa during transcontinental particle discharge between Africa and Europe. With the aim of verifying relative effects of dust outbreaks, sampling period, and sampling site on the airborne bacterial community composition, we compared air collected during dust-carrying meteorological events to that coming from wind regimes not associated with long-distance particle lifting. Results indicated that (a) higher microbial diversity and richness (118 vs. 65 orders) and increased community evenness were observed in the campaign carried out in September in comparison to the one in May, irrespective of the place of collection and of the presence or absence of dust outbreaks; (b) during the period of standard wind regimes without transcontinental outbreaks, a synchronous concerted turnover of bacterial communities across distant locations of the same island, accompanied as mentioned by a parallel rise in bacterial diversity and community evenness, appears to have occurred; (c) changes in wind provenance could transiently change community composition in the locality placed on the coast facing the incoming wind but not in the one located at the opposite side of the island, and for this reason the community changes brought from dust outbreaks of African origin are observed only in the sampling station exposed to the south; (d) the same winds, once proceeding over land, appear to uplift bacteria belonging to a common core already present over the region, which dilute or replace those that were associated with the air coming from the sea or conveyed by the dust particulates, explaining the two prior points; and (e) the hierarchy of the variables tested in determining bacterial assemblages composition results is as follows: sampling period≫ongoing meteorological events>sampling location within the island.

Cultivar susceptibility and environmental parameters affecting symptom expression of red leaf blotch of almond in Spain

Plant Disease ◽  
2020 ◽  
Author(s):  
Xavier Miarnau ◽  
Lourdes Zazurca ◽  
Laura Torguet ◽  
Erick Zúñiga ◽  
Ignasi Batlle ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Management Strategies ◽  
Environmental Parameters ◽  
Experimental Period ◽  
Symptom Expression ◽  
Leaf Blotch ◽  
Accumulated Rainfall ◽  
Summer Temperatures ◽  
Cultivar Susceptibility ◽  
The Mediterranean Basin

Red leaf blotch (RLB) of almond, caused by Polystigma amygdalinum, is an important foliar disease of this nut tree in the Mediterranean basin and Middle East regions. In recent years, the incidence of this disease has increased in Spain corresponding to increases in the area of newly-planted orchards and the use of susceptible cultivars. In 2009, an experimental orchard including 21 almond cultivars was planted at Les Borges Blanques, Lleida, NE Spain. No fungicide treatments were applied during the 10-year experimental period (2009-2018) in order to allow natural disease development. Cultivar susceptibility to RLB was assessed each year, from 2011 to 2018, through visual observations of symptoms in naturally-infected trees. The experimental results led us to classify the cultivars into five susceptibility groups. The most susceptible were 'Tarraco', 'Guara', 'Tuono', 'Marinada', 'Desmayo Largueta', and 'Soleta', whereas 'Mardía' was the most tolerant. The annual incidence of disease was positively correlated with accumulated rainfall in spring, and especially in April, while it was negatively correlated with high spring and summer temperatures, especially in May. These findings could be used to improve disease management strategies by identifying the most susceptible cultivars and improving the timing of fungicide application.

Nano- and Microplankton Dynamics during the Spring Phaeocystis Sp. Bloom in McMurdo Sound, Antarctica

1995 ◽  
Vol 75 (4) ◽  
pp. 815-832 ◽  
Author(s):  
Diane K. Stoecker ◽  
Mary Putt ◽  
Tiffany Moisan
Keyword(s):  
Food Web ◽  
Phytoplankton Biomass ◽  
Size Range ◽  
Sampling Period ◽  
Microbial Food Web ◽  
Seasonal Development ◽  
Mcmurdo Sound ◽  
Bloom Period ◽  
Abundance And Diversity ◽  
Trophic Linkages

The seasonal development of the microbial food web in eastern McMurdo Sound, Antarctica, was investigated during and immediately after the 1990–1991 bloom of Phaeocystis sp. (Prymnesiophyceae: Prymnesiales). From 23 November to 7 December, which was before the appearance of macroscopic colonies of Phaeocystis, both phytoplankton and Protozoa were low in abundance. During the Phaeocystis bloom (~10 December to 7 January), phytoplankton biomass was high and was dominated by colonial and singlecelled Phaeocystis, but other phytoplankton taxa, including diatoms and photosynthetic dinoflagellates, co-occurred. Heterotrophic nanoplankton and protozoan microzooplankton increased dramatically in biomass during the bloom. Non-thecate heterotrophic dinoflagellates were the most abundant microzooplankters. There was no evidence for inhibition of the microbial food web by Phaeocystis. By the post-bloom period, macroscopic colonies were rare and phytoplankton biomass had declined markedly. Microzooplankton biomass continued to rise until the end of the sampling period (23 January). Microfaecal pellets (median size range, 10–30 μm) were abundant during the bloom and post-bloom periods. In the post-bloom period, the heterotrophic protistan assemblage became very diverse, with numerous trophic linkages within the microbial food web. The abundance and diversity of the heterotrophic protist assemblage suggests that there was little control of protists by metazoans and that the microbial food web, consisting of bacteria, algae and Protozoa, was poorly coupled to metazoan zooplankton.

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