"Plants are members of complex communities and they interact with other plants, insects and microbes. These interactions have a high economic impact in agriculture, like is the case of pests and pathogens attacking a certain crop. Traditionally such interactions have been study one-by-one, but recently a high number of investigations are focused in the study of the relationships in a wider context. In the context of Integrated Pest Management, the use of strategies that induce plant resistance is a very promising strategy since it can be more effective than the use of pesticides in some cases The use of rhizobacteria is one method to induce systemic resistance in plants, as well as to promote plant growth. Induced defences comprise direct defences such as secondary metabolites and protease inhibitors that negatively affect herbivore growth and survival. And they also comprise indirect defences such as herbivore-induced plant volatiles and herbivore-induced extrafloral nectar that enhance the effectiveness of natural enemies of herbivores, such as parasitoids or predators. These mechanisms are providing plants two ways of defence against insect pests, and in the context of integrated pest management where natural enemies are frequently released, they can be very effective for pest control. It is essential to understand the mechanisms that are involved in these interactions in order to apply this strategy to the different plant-insect interactions."