scholarly journals The role of interference between vectors in control of plant diseases

2021 ◽  
Author(s):  
Marta Zaffaroni ◽  
Loup Rimbaud ◽  
Ludovic Mailleret ◽  
Nik Cunniffe ◽  
Daniele Bevacqua
Keyword(s):  
Disease Transmission ◽  
Management Strategies ◽  
Viral Disease ◽  
Plant Viruses ◽  
Plant Diseases ◽  
Agronomic Practices ◽  
Ecological Principles ◽  
Single Host ◽  
Primary Vector

Aphids are the primary vector of plant viruses. Transient aphids, which probe several plants per day, are considered to be the principal vectors of non-persistently transmitted (NPT) viruses. However, resident aphids, which can complete their life cycle on a single host and are affected by agronomic practices, can transmit NPT viruses as well. Moreover, they can interfere both directly and indirectly with transient aphids, eventually shaping plant disease dynamics. By mean of an epidemiological model, originally accounting for ecological principles and agronomic practices, we explore the consequences of fertilization and irrigation, pesticide deployment and roguing of infected plants on the spread of viral disease in crops. Our results indicate that the spread of NPT viruses can be i) both reduced or increased by fertilization and irrigation, depending on whether the interference is direct or indirect; ii) counter-intuitively increased by pesticide application and iii) reduced by roguing infected plants. We show that a better understanding of vectors' interactions would enhance our understanding of disease transmission, supporting the development of disease management strategies.

scholarly journals Modelling interference between vectors of non-persistently transmitted plant viruses to identify effective control strategies

2021 ◽  
Vol 17 (12) ◽  
pp. e1009727
Author(s):  
Marta Zaffaroni ◽  
Loup Rimbaud ◽  
Ludovic Mailleret ◽  
Nik J. Cunniffe ◽  
Daniele Bevacqua
Keyword(s):  
Disease Transmission ◽  
Plant Disease ◽  
Control Strategies ◽  
Management Strategies ◽  
Plant Viruses ◽  
Effective Control ◽  
Agronomic Practices ◽  
Ecological Principles ◽  
Single Host ◽  
Primary Vector

Aphids are the primary vector of plant viruses. Transient aphids, which probe several plants per day, are considered to be the principal vectors of non-persistently transmitted (NPT) viruses. However, resident aphids, which can complete their life cycle on a single host and are affected by agronomic practices, can transmit NPT viruses as well. Moreover, they can interfere both directly and indirectly with transient aphids, eventually shaping plant disease dynamics. By mean of an epidemiological model, originally accounting for ecological principles and agronomic practices, we explore the consequences of fertilization and irrigation, pesticide deployment and roguing of infected plants on the spread of viral diseases in crops. Our results indicate that the spread of NPT viruses can be i) both reduced or increased by fertilization and irrigation, depending on whether the interference is direct or indirect; ii) counter-intuitively increased by pesticide application and iii) reduced by roguing infected plants. We show that a better understanding of vectors’ interactions would enhance our understanding of disease transmission, supporting the development of disease management strategies.

scholarly journals Effects of Vector Maturation Time on the Dynamics of Cassava Mosaic Disease

2021 ◽  
Vol 83 (8) ◽  
Author(s):  
F. Al Basir ◽  
Y. N. Kyrychko ◽  
K. B. Blyuss ◽  
S. Ray
Keyword(s):  
Time Delay ◽  
Plant Density ◽  
Plant Viruses ◽  
Mosaic Disease ◽  
Plant Diseases ◽  
Cassava Mosaic Disease ◽  
Maturation Time ◽  
Negative Effect ◽  
Dynamical Regimes

AbstractMany plant diseases are caused by plant viruses that are often transmitted to plants by vectors. For instance, the cassava mosaic disease, which is spread by whiteflies, has a significant negative effect on plant growth and development. Since only mature whiteflies can contribute to the spread of the cassava mosaic virus, and the maturation time is non-negligible compared to whitefly lifetime, it is important to consider the effects this maturation time can have on the dynamics. In this paper, we propose a mathematical model for dynamics of cassava mosaic disease that includes immature and mature vectors and explicitly includes a time delay representing vector maturation time. A special feature of our plant epidemic model is that vector recruitment is negatively related to the delayed ratio between vector density and plant density. We identify conditions of biological feasibility and stability of different steady states in terms of system parameters and the time delay. Numerical stability analyses and simulations are performed to explore the role of various parameters, and to illustrate the behaviour of the model in different dynamical regimes. We show that the maturation delay may stabilise epidemiological dynamics that would otherwise be cyclic.

scholarly journals The Probing Behavior Component of Disease Transmission in Insect-Transmitted Bacterial Plant Pathogens

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 212 ◽  
Author(s):  
Timothy A. Ebert
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Disease Transmission ◽  
Plant Pathogens ◽  
Management Strategies ◽  
Resistance Mechanism ◽  
Electrical Circuit ◽  
Plant Diseases ◽  
Candidatus Liberibacter

Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management strategies. Management may be an insecticide applied to kill the vector or a host plant resistance mechanism to make the host plant less suitable for the vector. In either case, the tactic must act before the insect performs the key behavior(s) resulting in either acquisition or transmission. This requires knowledge of the timing of behaviors the insect uses to probe the plant and commence ingestion. These behaviors are visualized using electropenetrography (EPG), wherein the plant and insect become part of an electrical circuit. With the tools to define specific steps in the probing process, we can understand the timing of acquisition and inoculation. With that understanding comes the potential for more relevant testing of management strategies, through insecticides or host plant resistance. The primary example will be Candidatus Liberibacter asiaticus transmitted by Diaphorina citri Kuwayama in the citrus agroecosystem, with additional examples used as appropriate.

scholarly journals Applications of Proteomic Tools to Study Insect Vector–Plant Virus Interactions

Life ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 143
Author(s):  
Priyanka Mittapelly ◽  
Swapna Priya Rajarapu
Keyword(s):  
Protein Interactions ◽  
Plant Virus ◽  
Management Strategies ◽  
Viral Disease ◽  
Plant Viruses ◽  
Global Changes ◽  
Insect Vector ◽  
Insect Vectors ◽  
Biological Interactions ◽  
Bioinformatic Tools

Proteins are crucial players of biological interactions within and between the organisms and thus it is important to understand the role of proteins in successful partnerships, such as insect vectors and their plant viruses. Proteomic approaches have identified several proteins at the interface of virus acquisition and transmission by their insect vectors which could be potential molecular targets for sustainable pest and viral disease management strategies. Here we review the proteomic techniques used to study the interactions of insect vector and plant virus. Our review will focus on the techniques available to identify the infection, global changes at the proteome level in insect vectors, and protein-protein interactions of insect vectors and plant viruses. Furthermore, we also review the integration of other techniques with proteomics and the available bioinformatic tools to analyze the proteomic data.

scholarly journals Worldwide dynamic biogeography of zoonotic and anthroponotic dengue

2021 ◽  
Vol 15 (6) ◽  
pp. e0009496
Author(s):  
Alisa Aliaga-Samanez ◽  
Marina Cobos-Mayo ◽  
Raimundo Real ◽  
Marina Segura ◽  
David Romero ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Management Strategies ◽  
Viral Disease ◽  
Human Case ◽  
Transmission Risk ◽  
Predictive Capacity ◽  
Case Record ◽  
Global Pandemic ◽  
Dengue Transmission ◽  
Tropical Areas

Dengue is a viral disease transmitted by mosquitoes. The rapid spread of dengue could lead to a global pandemic, and so the geographical extent of this spread needs to be assessed and predicted. There are also reasons to suggest that transmission of dengue from non-human primates in tropical forest cycles is being underestimated. We investigate the fine-scale geographic changes in transmission risk since the late 20th century, and take into account for the first time the potential role that primate biogeography and sylvatic vectors play in increasing the disease transmission risk. We apply a biogeographic framework to the most recent global dataset of dengue cases. Temporally stratified models describing favorable areas for vector presence and for disease transmission are combined. Our models were validated for predictive capacity, and point to a significant broadening of vector presence in tropical and non-tropical areas globally. We show that dengue transmission is likely to spread to affected areas in China, Papua New Guinea, Australia, USA, Colombia, Venezuela, Madagascar, as well as to cities in Europe and Japan. These models also suggest that dengue transmission is likely to spread to regions where there are presently no or very few reports of occurrence. According to our results, sylvatic dengue cycles account for a small percentage of the global extent of the human case record, but could be increasing in relevance in Asia, Africa, and South America. The spatial distribution of factors favoring transmission risk in different regions of the world allows for distinct management strategies to be prepared.

scholarly journals The hunt for plant viruses in South Africa: The early days

2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Chrissie Rey
Keyword(s):  
South Africa ◽  
Management Strategies ◽  
Plant Viruses ◽  
Diagnostic Methods ◽  
Plant Diseases ◽  
Viral Diseases ◽  
Small Scale ◽  
Indigenous Plants ◽  
Accurate Identification ◽  
Potential Yield

Plant viruses cause widespread disease in agriculturally important crops, resulting in a reduction in both quality and quantity of produce. The introduction of intensive crop monoculture has resulted in an exponential increase in viral diseases which can cross over from wild indigenous plants. Viral pathogens also can occur in mixed infections, and rapid, sensitive and reliable diagnostic methods are required to identify and characterise the viruses responsible for the field diseases. In comparison to bacterial and fungal diseases, viral diseases are more difficult to diagnose. This review covers a period (1985–2011) in the history of virus discovery in South Africa during which several plant viruses from commercial and smallscale farms were identified and characterised. Interestingly, novel viruses were discovered in three crops, namely guar and cassava grown by small-scale farmers in Mpumalanga, and in commercial tobacco. The implication of these plant diseases is potential yield loss to farmers which can affect their livelihoods, and result in severe economic loss for the food and agriculture industries. Accurate identification of the causal viral agents of these viral diseases is a prerequisite for development of effective management strategies.

Moderating Role of Learning Strategies Between Meta-Cognitive Awareness and Study Habits Among University Students

2019 ◽  
Vol 34 (Spring 2019) ◽  
pp. 215-231
Author(s):  
Mussarat J. Khan ◽  
Seemab Rasheed
Keyword(s):  
Regression Analysis ◽  
Resource Management ◽  
University Students ◽  
Learning Strategies ◽  
Management Strategies ◽  
Cognitive Strategies ◽  
Study Habits ◽  
Good Reliability ◽  
Cognitive Awareness

The purpose of present study is to examine the role of learning strategies as moderator between meta-cognitive awareness and study habits among university students. Sample comprises of 200 students (100 male students and 100 female students) of various universities of Islamabad and Rawalpindi with age ranging from 18-25 years. In order to assess study variables questionnaires were used included Meta-Cognitive Awareness Inventory (Schraw & Dennison, 1994) measuring two-components of meta-cognition that are knowledge and regulation of cognition. Study habits demonstrated by the students were measured by the Study Habits Inventory (Wrenn, 1941). Motivated Strategies for Learning Questionnaire (Pintrich, Smith, Garcia, & McKeachie, 1991) which includes motivation and learning strategies scales. In the present study, only the learning strategies section was utilized, which measures the cognitive strategies and resource management strategies. Results revealed positive correlation between research instruments and are also having good reliability. Regression analysis reflected that meta-cognitive awareness predicts study habits among university students. Regression analysis also suggested that learning strategies including resource management strategies and cognitive strategies significantly moderates the relationship between meta-cognitive awareness and study habits. It is also explored gender differences on learning strategies, meta-cognitive awareness and study habits. Future implications of the study were also discussed.

BİLGİ YÖNETİMİ UYGULAMALARI KAPSAMINDA İNSAN KAYNAKLARI YÖNETİMİNDE MEYDANA GELEN DEĞİŞİMLER

2013 ◽  
Vol 1 (1) ◽  
pp. 83
Author(s):  
Ozan Büyükyılmaz
Keyword(s):  
Knowledge Management ◽  
Human Resources ◽  
Performance Management ◽  
Management Practices ◽  
Human Resources Management ◽  
Management Strategies ◽  
Resources Management ◽  
Management Philosophy ◽  
Management Processes

The development and expansion of knowledge management as an important management philosophy has a significant impact on human resources management as well as on organization as a whole. In this context, knowledge management processes have been used as a strategic tool within human resources management.Therefore, functions of human resources management must adapt itself to this change. The purpose of this study is to determine the role of human resources management in the management of knowledge and to reveal the effects of knowledge management practices on the functions of human resources byexamining the relationship between human resources and knowledge management. In this context, a theoretical investigation was conducted. It has been determined that significant changes occurred on the functions of human resources management such as selection and recruitment, performance management, remuneration and reward, training and development within the framework of the knowledge management strategies.

Plasma therapy a possible hope to fight against COVID-19

2020 ◽  
Author(s):  
Ravikant Piyush ◽  
Aroni Chatterjee ◽  
Shashikant Ray
Keyword(s):  
Middle East ◽  
Severe Acute Respiratory Syndrome ◽  
Viral Disease ◽  
Plasma Therapy ◽  
Therapeutic Drugs ◽  
Wild Fire ◽  
The World ◽  
Short Span ◽  
Game Changer

The world is currently going through a disastrous event and a catastrophic upheaval caused by the coronavirus disease 2019 (COVID-19). The pandemic has resulted in loss of more than 150000 deaths across the globe. Originating from China and spreading across all continents within a short span of time, it has become a matter of international emergency. Different agencies are adopting diverse approaches to stop and spread of this viral disease but still now nothing confirmatory has come up. Due to lack of vaccines and proper therapeutic drugs, the disease is still spreading like wild fire without control. An Old but very promising method- the convalescent plasma therapy could be the key therapy to stop this pandemic. This method has already proven its mettle on several occasions previously and has been found to be effective in curing the pandemics induced by Ebola, severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the same group of β-Coronavirus that has resulted in the above diseases. Therefore, the role of plasma therapy is being explored for treatment of this disease. In this review, we have mainly focused on the role of convalescent plasma therapy and why its use should be promoted in fight against COVID-19, as it could turn out to be a game changer.

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