The Effect of Spatial Distributions of Mycoparasites on Biocontrol Efficacy: a Modelling Approach

The effect of aggregation of pathogen and biocontrol microbe propagules on biocontrol potential: a simple modelling study

“…The dashed line indicates the median value propagules were the more variable and lower the biocontrol potential was. Unlike previous studies of biocontrol under spatially heterogeneous conditions (Liu et al 2000;Jeger et al 2004;Kessel et al 2005), the effects of initial aggregation of BCA and/or pathogen propagules on the biocontrol efficacy were not confounded with other dynamic aspects of BCA/pathogen development. Moreover, the present study investigated the joint effects of spatial heterogeneity on leaf surfaces and spatial distributional properties of pathogen/BCA propagules on biocontrol potential.…”

“…One important ecological trait affecting microbial population dynamics is related to the spatial distributional properties of their propagules and their abilities of being spatially dispersed. The spatial distribution and dispersal of propagules have been shown to affect biocontrol efficacies for specific pathosystems, including Ulocladium atrum against Botrytis cinerea (Kessel et al 2005), biocontrol of fungal pathogens with mycoviruses (Liu et al 2000), and mycoparasites against soilborne pathogens (Jeger et al 2004). Bacteria can form biofilms in response to external environmental conditions, which may affect biocontrol outcomes in terms of microbial survival and the extent of contact between antagonists and pathogens on the host tissue surface (Morris and Monier 2003;Nongkhlaw and Joshi 2014).…”

“…The initial distribution of introduced BCA propagules can largely influence their distance to pathogen propagules, affecting subsequent biocontrol outcomes. This is supported by a limited number of modelling studies, including a spatially explicit simulation study of Ulocladium atrum against Botrytis cinerea (Kessel et al 2005), spatial host heterogeneity in affecting biocontrol of fungal pathogens with mycoviruses (Liu et al 2000), and spatial distribution of mycoparasite propagules in soil on controlling soilborne pathogens (Jeger et al 2004). Furthermore, environmental heterogeneity, on both spatial and temporal scales, is the rule rather than an exception when foliar pathogens are concerned.…”

“…Specifically, we investigated the effects of the abundance and spatial aggregation of BCA/pathogen propagules, and the extent of environmental heterogeneity on biocontrol potential. Following a previous study (Jeger et al 2004), we used the distance between a pathogen propagule and its nearest BCA propagule to represent biocontrol potential. Such a distance is critically important for biocontrol outcomes, particularly for biocontrol mechanisms of competition and direct parasitism and, to a lesser extent, for localised antibiosis or induced resistance.…”

Field Management of Anthracnose (<i>Colletotrichum lindemuthianum</i>) in Common Bean through Foliar Spray Fungicides and Seed Treatment Bioagents

“…This could be due to high density of initial inoculum from the infected seeds. Experimental studies have shown that the rates of disease increase were considerably influenced by the number of initial disease foci (Xu and Ridout, 1998;Jerger et al, 2004). In an experiment with southern blight of processing carrot, the rate of disease increase generally increased as the number of initial foci increased (Smith et al, 1988).…”