This work takes place in the context of the experimental introduction of sterile males to fight the Mediterranean fruit fly Ceratitis capitata in orchard landscapes in Corsica (France). We first considered the natural population dynamics of the fly, by building a three-dimensional model structured in larva, male and female stages. The model was calibrated in part by compiling data from literature, and in part by ensuring that the predicted dynamics were comparable to those observed in the field. Competition between females was shown to be the deciding factor for the extent of the fly infestation. Further, a sensitivity analysis performed on larval density at the end of a cropping season showed it is most influenced by the per capita oviposition rate and the larval mortality rate. These two biological processes are thus important to control the C. capitata population. Stemming from that model, we introduced a sterile males - wild males - females model to represent the dynamics resulting from sterile males introductions. We first considered releases of perfectly sterile insects, but also two different situations accounting for residual fertility of the “sterile" males. We showed how residual fertility could destabilize the pest-free equilibrium, and gave a condition to be satisfied to ensure that the pest-free equilibrium is the only equilibrium, and that it is stable. The developments were carried out from qualitative properties on mating probability and competition between females, so that they hold true for a wide range of functional forms and situations. Generalizing the results brought forward in [1], we showed that, when residual fertility is below a threshold value, SIT could be made efficient by overflooding the landscape with sterile males. We additionaly proved that SIT could still be efficient beyond that threshold, as long as releases are not too massive, since it would result in also massively releasing fertile males. References [1] M.S. Aronna and Y. Dumont, On Nonlinear Pest/Vector Control via the Sterile Insect Technique: Impact of Residual Fertility, Bull Math Biol, 82(110), 2020.