Biological pest control is the eco-friendly method of controlling pests using natural enemies such as predators, pathogens, and parasitoids. It is one of the important components of IPM. Recent works on biological control focusing on the aspects of controlling economically damaging pest by introducing non-economically damaging pests as competitors. One of the ways to enhance the biological control is to provide suitable additional/alternative food to competitors. In this article, we study the dynamics of controlling the economically damaging pest species by providing additional food to non-economically damaging competitive pests. Mathematically these competitive interactions are modelled using Lokta-Volterra model of competition and with Holling type II functional response towards the additional food. The conditions on the quality and quantity of additional food under which successful biological control can be achieved have been obtained. The global dynamics of the systems have studied by analyzing various bifurcations that are occurring in the system. The study can aid the eco-managers, on the choice of competitive species and the additional food for accomplishing successful biological control. The results of the theoretical observations are in agreement with few field experiments. © 2016 Academic Publications, Ltd.