A mathematical modeling approach to assess biological control of an orange tree disease

The model presented and investigated here describes the interaction between the orange tree and two different microorganisms, the pathogen fungus Guignardia citricarpa and the antagonist Trichoderma harzianum T1A. The pathogen-free point and coexistence are the only possible system's equilibria. The pathogen-free point bifurcates from coexistence when the antagonist strength is sufficiently high, but does not appear to be much dependent on the amount of beneficial fungus employed. This result represents a relevant guideline for the applied ecologist and for the farmers. Sensitivity analysis in suitable parameter spaces is performed numerically.