The combined use of parasitoids and the SIT has been applied in several states in Mexico, to control populations of the Mexican fruit fly and the West Indies fruit fly. Release of both agents are carried out simultaneously, targeting with parasitoids the fruit fly larvae infesting fruit and the wild adults with sterilized released adults to prevent the wild population from reproducing. The parasitoids are mass-reared in fruit fly larvae that have been irradiated to prevent the emergence of adult flies from larvae that were not parasitized.In Costa Rica, a similar application is being used for parasitoids of the stable fly. The parasitoids have been successfully reared in sterilized larvae of this fly, which is its natural host. This fly is a pest of economic significance for the livestock industry in Costa Rica and many other IAEA Member States.