| Abstract | Spatial pattern of pathogen distribution in site of control in an agricultural ecosystem has a major role to play in strategic planning of control the pest population. As the spatial spread of disease depends on horizontal transmission of disease agents, there are numerous factors like pathogen susceptibility, host movement, abiotic components such as climate one, which influence the overall effectiveness of the control policy. Insects exhibit a variety of physiological, morphological and behavioral responses to infection, which can affect both pathogen and host fitness. Behavioral modifications caused by NPV might have some inevitable effect on virus transmission and dispersal as well as on the predation in the system. Infection makes the insects more vulnerable to predators to some extents. On contrary, predators do not take more deadly insects. Thus there always exist some trade off between infection strength (such as virulence, etc) and predation for successful spread of infection in the site of control. This also contributes to the risk assessment of biopesticides, particularly the genetically modified baculoviruses. As initiation of new infection cycle in the system depends on the number of infected inoculums in the site, so spatial movement of infected hosts during the course of infection (i.e., latency period) influence the dynamics. Moreover, infection develops some behavioral changes inthe host, which makes them more vulnerable to the natural enemies. Thus, overall infection process in the system depends on such interrelated factors. We derive a delayed reaction-diffusion system in one spatial dimension using Von-Foerster equation and compute the minimum traveling speed at which infection spreads for successful transmission. We show that the minimum speed depends on the various system parameters, such as diffusivity of infectives, force of infection, incubation period, etc. |
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