Mathematical modelling of the interaction of winter wheat (Triticum aestivum) and Fusarium species (Fusarium spp.)

Abstract

The existing methods of pathogen control in agroecosystems are insufficiently effective against Fusarium species due to the high variability and specific biology of these fungi . The aim of our work was to reconstruct the kinetic mechanisms that determine the biomass of Fusarium species in the agroecosystem, and to find out the optimal ways to manipulate the structure of detrital food webs, which would minimize the risk of Fusarium contamination. The studied system consisted of three components: mycophagous soil nematodes, the soil phase of Fusarium species, and winter wheat seedlings. Two system models were compared: general (based on general postulates of population dynamics) and lab-specific (taking into account the peculiarities of the conditions of the laboratory experiment). Based on the results of parameter estimation and global sensitivity analysis, three model parameters were identified with a strongest impact on the biomass of Fusarium species: (1) the reproduction rate of mycophagous nematodes due to the feeding on Fusarium, (2) the death rate of mycophagous nematodes, and (3) the carrying capacity of Fusarium species. Based on the results of stochastic modelling, the internal variability of the biomass dynamics of Fusarium species exceeded by two orders of magnitude the internal variability of abundance dynamics of mycophagous nematodes. The developed model made it possible to obtain fundamentally new information about the basic mechanisms of interaction of Fusarium species, mycophagous nematodes and winter wheat plants, and highlight the most promising mechanisms which can reduce the biomass of Fusarium species in the soil.