The core of PHOCUS is that it has to be fast and safe. For our project, we chose to model the temporal evolution of the number of bacteria, phages, and produced toxin. The aim of modelling is to gain insight in the feasibility of our biopesticide. Furthermore, as speed is one of design requirements of PHOCUS, we used modelling to gain insight in the production speed of the locust specific toxins inside the locust gut.