  In this paper we will consider a mathematical model that describes, the
tritrophic interaction between plants, herbivores and their natural enemies,
where volatiles organic compounds (VOCs) released by plants play an important
role. We show positivity and boundedness of the system solutions, existence of
positive equilibrium and its local stability, we analyse global stability of
positive equilibrium via the geometrical approach of Li and Muldowney. We pay
attention to parameters in order to discuss different types of bifurcations.
Finally, we present some numerical simulations to justify our analytical
results.
