scholarly journals Greening Incidence and Greening Vector Population Dynamics in Pokhara

1988 ◽  
Vol 10 (10) ◽  
Author(s):  
C. Regmi ◽  
T. K. Lama
Keyword(s):  
Population Dynamics ◽  
Vector Population

scholarly journals Epidemiological and ecological consequences of virus manipulation of host and vector in plant virus transmission

2021 ◽  
Author(s):  
Nik J. Cunniffe ◽  
Nick P. Taylor ◽  
Frédéric M. Hamelin ◽  
Michael J. Jeger
Keyword(s):  
Population Dynamics ◽  
Plant Virus ◽  
Complex Dynamics ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Infection Status ◽  
Vector Behaviour ◽  
Interactive Interface ◽  
Vector Population ◽  
Plant Infection

ABSTRACTMany plant viruses are transmitted by insect vectors. Transmission can be described as persistent or non-persistent depending on rates of acquisition, retention, and inoculation of virus. Much experimental evidence has accumulated indicating vectors can prefer to settle and/or feed on infected versus noninfected host plants. For persistent transmission, vector preference can also be conditional, depending on the vector’s own infection status. Since viruses can alter host plant quality as a resource for feeding, infection potentially also affects vector population dynamics. Here we use mathematical modelling to develop a theoretical framework addressing the effects of vector preferences for landing, settling and feeding – as well as potential effects of infection on vector population density – on plant virus epidemics. We explore the consequences of preferences that depend on the host (infected or healthy) and vector (viruliferous or nonviruliferous) phenotypes, and how this is affected by the form of transmission, persistent or non-persistent. We show how different components of vector preference have characteristic effects on both the basic reproduction number and the final incidence of disease. We also show how vector preference can induce bistability, in which the virus is able to persist even when it cannot invade from very low densities. Feedbacks between plant infection status, vector population dynamics and virus transmission potentially lead to very complex dynamics, including sustained oscillations. Our work is supported by an interactive interface https://plantdiseasevectorpreference.herokuapp.com/. Our model reiterates the importance of coupling virus infection to vector behaviour, life history and population dynamics to fully understand plant virus epidemics.

scholarly journals A dynamically-structured matrix population model based on renewal processes for accumulative development under variable environmental conditions

2021 ◽  
Author(s):  
Kamil Erguler ◽  
Jacob Mendel
Keyword(s):  
Population Dynamics ◽  
Environmental Conditions ◽  
Transmission Rate ◽  
Life Stage ◽  
Erlang Distribution ◽  
Vector Population ◽  
Structured Population ◽  
Population Dynamics Model ◽  
Time Required ◽  
The Impact

Arthropod vectors are responsible for the transmission of pathogens in humans and other species. The transmission rate depends on the size and activity of the vector population, factors which are in turn strongly affected by environmental conditions. Therefore, in order to develop realistic representations of vector population dynamics, it is necessary to properly account for the impact of a changing environment on the duration of life processes. Here, we use a pseudo-stage-structured population to model the accumulative process of development as a renewal process with a variable rate that depends on the environment. We incorporate this into sPop, formerly an age-structured population dynamics model. This framework allows the modeller to represent realistic life stage durations by choosing from three alternative probability schemes: an Erlang distribution, a Pascal distribution, or a fixed duration, while enabling the model to respond appropriately to variations in stage duration characteristics. Using this approach, we demonstrate that introducing random variation into the environmental conditions, which results in fluctuating development rates, on average decreases the time required for stage completion. An exception to this is an already optimum development rate being perturbed by noise towards a less efficient course. The proposed framework is suitable for performing inverse modelling with data collected from highly variable environmental conditions, the results of which can be used to develop realistic climate-driven population dynamics models.

scholarly journals Ecology of West Nile virus across four European countries: review of weather profiles, vector population dynamics and vector control response

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Chaskopoulou ◽  
Gregory L’Ambert ◽  
Dusan Petric ◽  
Romeo Bellini ◽  
Marija Zgomba ◽  
...  
Keyword(s):  
Population Dynamics ◽  
West Nile Virus ◽  
Vector Control ◽  
European Countries ◽  
West Nile ◽  
Vector Population ◽  
Control Response

scholarly journals Epidemiological and ecological consequences of virus manipulation of host and vector in plant virus transmission

2021 ◽  
Vol 17 (12) ◽  
pp. e1009759
Author(s):  
Nik J. Cunniffe ◽  
Nick P. Taylor ◽  
Frédéric M. Hamelin ◽  
Michael J. Jeger
Keyword(s):  
Population Dynamics ◽  
Plant Virus ◽  
Complex Dynamics ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Infection Status ◽  
Vector Behaviour ◽  
Interactive Interface ◽  
Vector Population ◽  
Plant Infection

Many plant viruses are transmitted by insect vectors. Transmission can be described as persistent or non-persistent depending on rates of acquisition, retention, and inoculation of virus. Much experimental evidence has accumulated indicating vectors can prefer to settle and/or feed on infected versus noninfected host plants. For persistent transmission, vector preference can also be conditional, depending on the vector’s own infection status. Since viruses can alter host plant quality as a resource for feeding, infection potentially also affects vector population dynamics. Here we use mathematical modelling to develop a theoretical framework addressing the effects of vector preferences for landing, settling and feeding–as well as potential effects of infection on vector population density–on plant virus epidemics. We explore the consequences of preferences that depend on the host (infected or healthy) and vector (viruliferous or nonviruliferous) phenotypes, and how this is affected by the form of transmission, persistent or non-persistent. We show how different components of vector preference have characteristic effects on both the basic reproduction number and the final incidence of disease. We also show how vector preference can induce bistability, in which the virus is able to persist even when it cannot invade from very low densities. Feedbacks between plant infection status, vector population dynamics and virus transmission potentially lead to very complex dynamics, including sustained oscillations. Our work is supported by an interactive interface https://plantdiseasevectorpreference.herokuapp.com/. Our model reiterates the importance of coupling virus infection to vector behaviour, life history and population dynamics to fully understand plant virus epidemics.

Xylella fastidiosa and Glassy-Winged Sharpshooter Population Dynamics in the Southern San Joaquin Valley of California

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2994-3001 ◽  
Author(s):  
Mark S. Sisterson ◽  
Lindsey P. Burbank ◽  
Rodrigo Krugner ◽  
David Haviland ◽  
Drake C. Stenger
Keyword(s):  
Population Dynamics ◽  
Xylella Fastidiosa ◽  
Late Summer ◽  
Early Summer ◽  
San Joaquin Valley ◽  
Pierce's Disease ◽  
Homalodisca Vitripennis ◽  
Pierce’S Disease ◽  
Vector Population ◽  
Pathogen Populations

Xylella fastidiosa is a vector-transmitted bacterial plant pathogen that affects a wide array of perennial crops, including grapevines (Pierce’s disease). In the southern San Joaquin Valley of California, epidemics of Pierce’s disease of grapevine were associated with the glassy-winged sharpshooter, Homalodisca vitripennis. During the growing season, rates of X. fastidiosa spread in vineyards are affected by changes in pathogen distribution within chronically infected grapevines and by vector population dynamics. Grapevines chronically infected with X. fastidiosa rarely tested positive for the pathogen prior to July, suggesting vector acquisition of X. fastidiosa from grapevines increases as the season progresses. This hypothesis was supported by an increase in number of X. fastidiosa-positive glassy-winged sharpshooters collected from vineyards during July through September. Analysis of insecticide records indicated that vineyards in the study area were typically treated with a systemic neonicotinoid in spring of each year. As a result, abundance of glassy-winged sharpshooters was typically low in late spring and early summer, with abundance of glassy-winged sharpshooter adults increasing in late June and early July of each year. Collectively, the results suggest that late summer is a crucial time for X. fastidiosa secondary spread in vineyards in the southern San Joaquin Valley, because glassy-winged sharpshooter abundance, number of glassy-winged sharpshooters testing positive for X. fastidiosa, and grapevines with detectable pathogen populations were all greatest during this period.

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