scholarly journals High Incidence of Preharvest Colonization of Huanglongbing-Symptomatic Citrus sinensis Fruit by Lasiodiplodia theobromae (Diplodia natalensis) and Exacerbation of Postharvest Fruit Decay by That Fungus

2014 ◽  
Vol 81 (1) ◽  
pp. 364-372 ◽  
Author(s):  
Wei Zhao ◽  
Jinhe Bai ◽  
Greg McCollum ◽  
Elizabeth Baldwin
Keyword(s):  
Hydrolytic Enzymes ◽  
Citrus Fruit ◽  
Decay Rates ◽  
Causal Organism ◽  
Lasiodiplodia Theobromae ◽  
Content Type ◽  
Surface Sterilization ◽  
Fruit Drop ◽  
Liberibacter Asiaticus ◽  
The Impact

ABSTRACTHuanglongbing (HLB), presumably caused by the bacterium “CandidatusLiberibacter asiaticus,” is a devastating citrus disease associated with excessive preharvest fruit drop.Lasiodiplodia theobromae(diplodia) is the causal organism of citrus stem end rot (SER). The pathogen infects citrus fruit under the calyx abscission zone (AZ-C) and is associated with cell wall hydrolytic enzymes similar to plant enzymes involved in abscission. By means of DNA sequencing, diplodia was found in “Ca. Liberibacter asiaticus”-positive juice from HLB-symptomatic fruit (S) but not in “Ca. Liberibacter asiaticus”-negative juice. Therefore, the incidence of diplodia in fruit tissues, the impact on HLB-related postharvest decay, and the implications for HLB-related preharvest fruit drop were investigated in Hamlin and Valencia oranges. Quantitative PCR results (qPCR) revealed a significantly (P< 0.001) greater incidence of diplodia in the AZ-C of HLB-symptomatic (S; “Ca. Liberibacter asiaticus” threshold cycle [CT] of <30) than in the AZ-C of in asymptomatic (AS; “Ca. Liberibacter asiaticus”CTof ≥30) fruit. In agreement with the qPCR results, 2 weeks after exposure to ethylene, the incidences of SER in S fruit were 66.7% (Hamlin) and 58.7% (Valencia), whereas for AS fruit the decay rates were 6.7% (Hamlin) and 5.3% (Valencia). Diplodia colonization of S fruit AZ-C was observed by scanning electron microscopy and confirmed by PCR test and morphology of conidia in isolates from the AZ-C after surface sterilization. DiplodiaCTvalues were negatively correlated with ethylene production (R= −0.838 for Hamlin;R= −0.858 for Valencia) in S fruit, and positively correlated with fruit detachment force (R= 0.855 for Hamlin;R= 0.850 for Valencia), suggesting that diplodia colonization in AZ-C may exacerbate HLB-associated preharvest fruit drop.

scholarly journals Effects of Curing on Green Mold and Stem-End Rot of Citrus Fruit and Its Potential Application Under Florida Packing System

Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 834-840 ◽  
Author(s):  
Jiuxu Zhang ◽  
Patricia P. Swingle
Keyword(s):  
Potential Application ◽  
Mycelial Growth ◽  
Citrus Fruit ◽  
Penicillium Digitatum ◽  
Curing Time ◽  
Lasiodiplodia Theobromae ◽  
Green Mold ◽  
Florida Citrus ◽  
The Impact ◽  
Packing System

The potential of citrus fruit curing for the control of green mold caused by Penicillium digitatum, and the impact of this treatment on stem-end rot caused by Lasiodiplodia theobromae were investigated. The optimum temperatures for mycelial growth of P. digitatum and L. theobromae were about 25 and 30°C, respectively. P. digitatum did not grow at 35°C, while L. theobromae did. Injuries of ‘Valencia’ oranges developed less green mold disease at 30 and 35°C than at 25°C or lower. Green mold incidences on ‘Valencia’ oranges treated at 21°C (uncured control), 30 and 35°C for 48 h were 51, 17.4, and 0%, respectively, for inoculated fruit, and 18.8, 11.4, and 0%, respectively, for wounded fruit after 2 weeks of storage at 21°C. However, a significant increase in stem-end rot occurred at 35°C when compared with 21°C (uncured control). In two of three different tests, curing fruit at 35°C for 48 h achieved better green mold control than a shorter curing time of 24 h. Curing ‘Pineapple’ oranges showed a similar or better efficacy for green mold control than imazalil at 500 and 1,000 ppm applied by either dip or packingline drip. The combination of thiabendazole drench (500 ppm) and curing of wounded ‘Valencia’ oranges and inoculated ‘Flame’ grapefruit reduced both green mold and stem-end rot by more than 93%. This study suggests that curing (35°C for 48 h) could be integrated into the current Florida citrus packing system to effectively control postharvest decays.

scholarly journals Lasiodiplodia theobromae as a Causal Agent of Kumquat Dieback in Taiwan

Plant Disease ◽  
2004 ◽  
Vol 88 (12) ◽  
pp. 1383-1383 ◽  
Author(s):  
W. H. Ko ◽  
I. T. Wang ◽  
P. J. Ann
Keyword(s):  
Agricultural Research ◽  
Citrus Fruit ◽  
Causal Organism ◽  
Disease Symptoms ◽  
Lasiodiplodia Theobromae ◽  
Whole Wheat ◽  
Initial Symptoms ◽  
Pathogenicity Tests ◽  
Symptomatic Tissue ◽  
Plant Pathol

Kumquat (Fortunella margarita (Lour.) Swingle) is an important citrus fruit crop of Iland County in northeastern Taiwan. Fruit produced in this area are mainly for making preserves, which is a well-known product in Taiwan. Decline of kumquat was first noticed in 1990. Since 1995, it has become an important problem affecting ≈80% of kumquat orchards. The problem was especially serious after the passage of a typhoon. Some orchards were abandoned due to death of many declining trees. Initial symptoms were yellowing and browning of leaves on some branches of affected trees. Abscission of leaves and fruits occurred, subsequently resulting in the appearance of dieback of affected branches. Disease symptoms could progress to other branches of the same tree, gummosis on the trunk, and eventually death of the tree. Previously, Phytophthora citrophthora (Smith & Smith) Leonian was reported to be a causal organism of kumquat decline (1). Recently, isolations from declining kumquat trees in several orchards failed to recover P. citrophthora and instead we isolated Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (syn. Botryodiplodia theobromae Pat.) from tissue taken from the margin of discolored bark and wood on symptomatic branches. The fungus produced grayish black colonies on V8 agar and black ostiolate pycnidia (125 to 650 μm in diameter) with ovoid to elongate conidia (20 to 32 × 12 to 16 μm) on autoclaved whole wheat grains that were placed on V8 agar. Young conidia were hyaline and nonseptate, whereas mature conidia were brown, one septate, and striate. Pathogenicity tests were carried out on healthy kumquat trees located at the Taiwan Agricultural Research Institute experimental farm. Three isolates of L. theobromae were cultured on wheat-oat medium. Colonized grains (≈5 g) were held against a wound made by lightly scrapping a branch (5 to 7 mm in diameter) 200 to 250 cm above the ground by wrapping a sheet of clear plastic around the branch (2). Eighteen branches were used for each isolate, and the same number of branches similarly inoculated with sterile grains as a control. Healthy branches inoculated with L. theobromae showed disease symptoms similar to those observed on naturally infected plants. Discoloration of leaves on inoculated branches occurred within 1 week. Subsequently, all the leaves fell and infected branches died. The numbers of inoculated branches killed by the three isolates of L. theobromae tested were 18, 9, and 14 after 1 month. All control branches remained disease free. L. theobromae was reisolated from symptomatic tissues, completing Koch's postulates. The same isolates were used to inoculate trunks of kumquat trees with the method described above. Six trunks were inoculated with each isolate, and the same number of trunks similarly inoculated with sterile grains was used as the control. Gummosis on inoculated trunks occurred in 1 week. The numbers of inoculated trunks showing gummosis induced by the three isolates of L. theobromae tested were 6, 5, and 6 after 1 month. L. theobromae was reisolated from symptomatic tissue. All control trunks remained free of gummosis. Our results show that in addition to P. citrophthora, L. theobromae can also cause a dieback on kumquat. To our knowledge, this is the first report of disease caused by L. theobromae on kumquat or on any species in the Rutaceae family in Taiwan. References: (1) P. J. Ann et al. Plant Pathol. Bull. (Taiwan) 6:198, 1997. (2) W. H. Ko et al. Plant Pathol. 35:254, 1986.

scholarly journals Transformative Approach To Investigate the Microphysical Factors Influencing Airborne Transmission of Pathogens

2020 ◽  
Vol 86 (23) ◽  
Author(s):  
Mara Otero Fernandez ◽  
Richard J. Thomas ◽  
Henry Oswin ◽  
Allen E. Haddrell ◽  
Jonathan P. Reid
Keyword(s):  
Escherichia Coli ◽  
Culture Medium ◽  
Local Environment ◽  
Decay Rates ◽  
Biological Assessment ◽  
Cloud Formation ◽  
Organic Chemical ◽  
Content Type ◽  
Transformative Approach ◽  
The Impact

ABSTRACT Emerging outbreaks of airborne pathogenic infections worldwide, such as the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, have raised the need to understand parameters affecting the airborne survival of microbes in order to develop measures for effective infection control. We report a novel experimental strategy, TAMBAS (tandem approach for microphysical and biological assessment of airborne microorganism survival), to explore the synergistic interactions between the physicochemical and biological processes that impact airborne microbe survival in aerosol droplets. This innovative approach provides a unique and detailed understanding of the processes taking place from aerosol droplet generation through to equilibration and viability decay in the local environment, elucidating decay mechanisms not previously described. The impact of evaporation kinetics, solute hygroscopicity and concentration, particle morphology, and equilibrium particle size on airborne survival are reported, using Escherichia coli MRE162 as a benchmark system. For this system, we report that (i) particle crystallization does not directly impact microbe longevity, (ii) bacteria act as crystallization nuclei during droplet drying and equilibration, and (iii) the kinetics of size and compositional change appear to have a larger effect on microbe longevity than the equilibrium solute concentration. IMPORTANCE A transformative approach to identify the physicochemical processes that impact the biological decay rates of bacteria in aerosol droplets is described. It is shown that the evaporation process and changes in the phase and morphology of the aerosol particle during evaporation impact microorganism viability. The equilibrium droplet size was found to affect airborne bacterial viability. Furthermore, the presence of Escherichia coli MRE162 in a droplet does not affect aerosol growth/evaporation but influences the dynamic behavior of the aerosol by processing the culture medium prior to aerosolization, affecting the hygroscopicity of the culture medium; this highlights the importance of the inorganic and organic chemical composition within the aerosolized droplets that impact hygroscopicity. Bacteria also act as crystallization nuclei. The novel approach and data have implications for increased mechanistic understanding of aerosol survival and infectivity in bioaerosol studies spanning the medical, veterinary, farming, and agricultural fields, including the role of microorganisms in atmospheric processing and cloud formation.

The More Control, the Better?

2014 ◽  
Vol 26 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Jeeyun Oh ◽  
Mun-Young Chung ◽  
Sangyong Han
Keyword(s):  
Mixed Design ◽  
Negative Effects ◽  
Story Structure ◽  
Content Type ◽  
High User ◽  
User Control ◽  
Rigorous Research ◽  
Control Versus ◽  
The Media ◽  
The Impact

Despite of the popularity of interactive movie trailers, rigorous research on one of the most apparent features of these interfaces – the level of user control – has been scarce. This study explored the effects of user control on users’ immersion and enjoyment of the movie trailers, moderated by the content type. We conducted a 2 (high user control versus low user control) × 2 (drama film trailer versus documentary film trailer) mixed-design factorial experiment. The results showed that the level of user control over movie trailer interfaces decreased users’ immersion when the trailer had an element of traditional story structure, such as a drama film trailer. Participants in the high user control condition answered that they were less fascinated with, absorbed in, focused on, mentally involved with, and emotionally affected by the movie trailer than participants in the low user control condition only with the drama movie trailer. The negative effects of user control on the level of immersion for the drama trailer translated into users’ enjoyment. The impact of user control over interfaces on immersion and enjoyment varies depending on the nature of the media content, which suggests a possible trade-off between the level of user control and entertainment outcomes.

ASSESSMENT OF GRAY FOREST SOIL ENZYMATIC ACTIVITY IN AGRICULTURAL SYSTEMS

2019 ◽  
Keyword(s):  
Enzymatic Activity ◽  
Environmental Sustainability ◽  
Hydrolytic Enzymes ◽  
Invertase Activity ◽  
Phosphorus Cycle ◽  
Soil Enzymatic Activity ◽  
Urease Enzyme ◽  
Natural Analogues ◽  
Activity Of Enzymes ◽  
The Impact

On the grey forest medium-loamy soil of Vladimir Opolye region we have studied the impact of various methods of basic cultivation and fertilizer systems on the activity of redox and hydrolytic enzymes: ure-ase (nitrogen cycle), invertase (carbon cycle), phosphatase (phosphorus cycle), and catalase, involved in the cycle of carbon in the soil. The second humus horizon with capacity of 19-24cm was found at the depth of 20 - 21 cm on the experimental field. We have studied three modes of basic soil cultivation: an-nual shallow flat plowing (6-8 cm), annual deep flat plowing (20-22 cm), and annual moldboard plowing (20-22 cm) with normal and intensive application of fertilizers. The most enzymatically active layer is 0-20 cm. No relevant difference has been found in the level of enzymes activity between variants of basic soil treatment. Activity of enzymes increases with application of fertilizers on the intensive background. In agrogenic soils, soil enzymatic activity is lower on average by 16-22% compared to the soil of the res-ervoir. The biggest negative transformation of activity has been observed at the urease enzyme (up to 50%). With annual moldboard plowing on the intensive backgroung, enzyme activity has been close to the natural level – 98.4%. Catalise and invertase activity in this case were found to be higher (105 and 116% respectively) than that of natural analogues. Activity of enzymes increases with intensive application of fertilizers as compared with normal background. This is particularly evident with 6-8cm deep beardless plowing and 20-22cm deep moldboard plowing. In general, the obtained biochemical indicators charac-terize the highest environmental sustainability of this variation within our research.

Perceived workplace gender-bias and psychological impact

2019 ◽  
Vol 43 (3/4) ◽  
pp. 339-353 ◽  
Author(s):  
Siham Lekchiri ◽  
Cindy Crowder ◽  
Anna Schnerre ◽  
Barbara A.W. Eversole
Keyword(s):  
Gender Bias ◽  
Critical Incident ◽  
Psychological Impact ◽  
Working Women ◽  
Content Type ◽  
Treatment Bias ◽  
Male Dominated ◽  
The Impact ◽  
Organizational Mechanisms ◽  
Practical Implications

Purpose The purpose of this paper is to explore the experiences of working women in a male-dominated country (Morocco) and unveil the unique challenges and everyday gender-bias they face, the psychological impact of the perceived gender-bias and, finally, identify a variety of coping strategies or combatting mechanisms affecting their motivation and retention in the workplace. Design/methodology/approach Empirical evidence was obtained using a qualitative research method. The Critical Incident Technique (CIT) was used to collect incidents recalled by women in the select institution reflecting their perceptions of their managers’ ineffective behaviors towards them and the impact of these behaviors. The critical incidents were inductively coded, and behavioral statements were derived from the coded data. Findings The qualitative data analysis led them to structure the data according to two theme clusters: The perceived gender-bias behaviors (Covert and evident personal and organizational behaviors) and Psychological impacts resulting from the perceived bias. These behavioral practices included abusive behaviors, unfair treatment, bias and lack of recognition. The psychological impact elements involved decreased productivity, depression, anxiety and low self-esteem. Practical implications Understanding these experiences can facilitate the identification of strategies geared towards the retention of women in the workforce, and Moroccan organizations can develop and implement strategies and policies that are geared towards eliminating gender-bias in the workplace and to retaining and motivating women who remain ambitious to work in male-dominated environments and cultures. Originality/value This paper provides evidence that sufficient organizational mechanisms to support women in male-dominated environments are still unavailable, leaving them to find the proper coping mechanisms to persevere and resist.

An empirical examination of firm financial performance along dimensions of supply chain resilience

2017 ◽  
Vol 40 (3) ◽  
pp. 254-269 ◽  
Author(s):  
Xun Li ◽  
Qun Wu ◽  
Clyde W. Holsapple ◽  
Thomas Goldsby
Keyword(s):  
Supply Chain ◽  
Financial Performance ◽  
Three Dimensions ◽  
Empirical Examination ◽  
Content Type ◽  
Supply Chain Resilience ◽  
Critical Dimensions ◽  
Firm Financial Performance ◽  
Supply Chain Agility ◽  
The Impact

Purpose This paper aims to investigate the impact of three critical dimensions of supply chain resilience, supply chain preparedness, supply chain alertness and supply chain agility, all aimed at increasing a firm’s financial outcomes. In a turbulent environment, firms require resilience in their supply chains to prepare for potential changes, detect changes and respond to actual changes, thus providing superior value. Design/methodology/approach Using survey data from 77 firms, this study develops scales for preparedness, alertness and agility. It then tests their hypothesized relationships with a firm’s financial performance. Findings The results reveal that the three dimensions of supply chain resilience (i.e. preparedness, alertness and agility) significantly impact a firm’s financial performance. It is also found that supply chain preparedness, as a proactive resilience capability, has a greater influence on a firm’s financial performance than the reactive capabilities including alertness and agility, suggesting that firms should pay more attention to proactive approaches for building supply chain resilience. Originality/value First, this study develops a comparatively comprehensive definition for supply chain resilience and explores its dimensionality. Second, this study provides empirically validated instruments for the dimensions of supply chain resilience. Third, this study is one of the first to provide empirical evidence for direct impact of supply chain resilience dimensions on a firm’s financial performance.

Proprietary information and the cost of bank debt

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
HyunJun Na
Keyword(s):  
Least Square ◽  
Bank Loan ◽  
Content Type ◽  
Loan Contracts ◽  
Proprietary Information ◽  
Banking Deregulation ◽  
Interstate Banking ◽  
Innovative Firms ◽  
Bank Loan Contracts ◽  
The Impact

PurposeThis study explores how the firm’s proprietary information has an impact on the bank loan contracts. It explains the propensity of using the competitive bid option (CBO) in the syndicate loans to solicit the best bid for innovative firms and how it changes based on industry competition and the degree of innovations. This research also examines how the interstate banking deregulation (Interstate Banking and Branching Efficiency Act) in 1994 affected the private loan contracts for innovative borrowers.Design/methodology/approachThe study uses various econometric analyses. First, it uses the propensity score matching analysis to see the impact of patents on pricing terms. Second, it uses the two-stage least square (2SLS) analysis by implementing the litigation and non-NYSE variables. Finally, it studies the impact of the policy change of the Interstate Banking and Branching Efficiency Act of 1994 on the bank loan contracts.FindingsFirms with more proprietary information pays more annual facility fees but less other fees. The patents are the primary determinants of the usage of CBO in the syndicate loans to solicit the best bid. While innovative firms can have better contract conditions by the CBO, firms with more proprietary information will less likely to use the CBO option to minimize the leakage of private information and the severe monitoring from the banks. Finally, more proprietary information lowered the loan spread for firms dependent on the external capital after the interstate banking deregulation.Originality/valueThe findings of this research will help senior executives with responsibility for financing their innovative projects. In addition, these findings should prove helpful for the lawmakers to boost economies.

The effect of emotions, eWOM quality and online review sequence on consumer intention to follow advice obtained from digital services

2020 ◽  
Vol 31 (3) ◽  
pp. 465-487 ◽  
Author(s):  
Carla Ruiz-Mafe ◽  
Enrique Bigné-Alcañiz ◽  
Rafael Currás-Pérez
Keyword(s):  
Structural Model ◽  
Online Reviews ◽  
Moderating Effect ◽  
Online Information ◽  
Bias Effect ◽  
Content Type ◽  
Digital Services ◽  
Information Cues ◽  
Cognitive Information ◽  
The Impact

PurposeThis paper analyses the interrelationships between emotions, the cognitive information cues of online reviews and intention to follow the advice obtained from digital platforms, paying special attention to the moderating effect of the sequencing of review valence.Design/methodology/approachThe data were collected from 830 Spanish Tripadvisor users. In a two-step approach, a measurement model was estimated and a structural model analysed to test the proposed hypotheses. SmartPLS 3.0 software was used. The moderating effect of sequencing of reviews is tested.FindingsThe data analysis showed a bias effect of review sequence on the impact of online information cues and emotions on intention to follow advice obtained from Tripadvisor. When the online reviews of a restaurant begin with positive commentaries, their perceived persuasiveness is a stronger driver of the pleasure and arousal elicited by online reviews than when they begin with negative reviews. On the other hand, the perceived helpfulness of online reviews only triggers arousal when the user reads negative, followed by positive, comments. The impact of pleasure on intention to follow the advice provided in an online travel community is higher with positive-negative than with negative-positive sequences.Originality/valueWhile researchers have demonstrated the benefits of customer reviews on company sales, a largely uninvestigated issue is the interplay between emotions and cognitive information cues in the processing of online reviews. This is one of the first studies to examine the moderating effect of conflicting reviews on the impact of emotions and cognitive information cues on consumer intention to follow the advice obtained from digital services.

The role of innovation in building competitive advantages: an empirical investigation

2018 ◽  
Vol 21 (1) ◽  
pp. 44-69 ◽  
Author(s):  
Prodromos Chatzoglou ◽  
Dimitrios Chatzoudes
Keyword(s):  
Competitive Advantage ◽  
Conceptual Framework ◽  
Empirical Investigation ◽  
Primary Data ◽  
Empirical Literature ◽  
Competitive Advantages ◽  
Manufacturing Companies ◽  
Content Type ◽  
The Impact ◽  
Structured Questionnaire

Purpose Nowadays, innovation appears as one of the main driving forces of organisational success. Despite the above fact, its impact on the propensity of an organisation to develop and sustain a competitive advantage has not yet received sufficient empirical investigation. The purpose of this paper is to enhance the existing empirical literature by focusing on the antecedents of innovation and its impact on competitive advantage. It proposes a newly developed conceptual framework that adopts a three-step approach, highlighting areas that have rarely been simultaneously examined before. Design/methodology/approach The examination of the proposed conceptual framework was performed with the use of a newly developed structured questionnaire that was distributed to a group of Greek manufacturing companies. The questionnaire has been successfully completed by chief executive officers (CEOs) from 189 different companies. CEOs were used as key respondents due to their knowledge and experience. The reliability and the validity of the questionnaire were thoroughly examined. Empirical data were analysed using the structural equation modelling technique. The study is empirical (based on primary data), explanatory (examines cause and effect relationships), deductive (tests research hypotheses) and quantitative (includes the analysis of quantitative data collected with the use of a structured questionnaire). Findings Results indicate that knowledge management, intellectual capital, organisational capabilities and organisational culture have significant direct and indirect effects on innovation, underlining the importance of their simultaneous enhancement. Finally, the positive effect of innovation on the creation of competitive advantages is empirically validated, bridging the gap in the relevant literature and offering avenues for additional future research. Originality/value The causal relationship between innovation and competitive advantage, despite its significant theoretical support, has not been empirically validated. The present paper aspires to bridge this gap, investigating the impact of innovation on the development of competitive advantages. Moreover, the present study adopts a multidimensional approach that has never been explored in the existing innovation literature, making the examination of the proposed conceptual framework an interesting research topic.

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