Abstract: The astonishing biodiversity of parasitic Hymenoptera and the large variety ofstrategies they use to colonize and exploit their insect hosts offer a wealth of molecular tools thatcan be profitably used for pest control. The virulence factors encoded by parasitic wasps and theirassociated symbionts are able to suppress the immune response of the host and to disrupt itsphysiological and reproductive processes. These molecules can directly target insect pests, and,by disrupting their immune response, they can also enhance the value of the ecological servicesoffered by natural antagonists. The use of these natural bionsecticides is highly dependent on thedevelopment of targeted delivery strategies, which have to be designed to enhance both theefficacy and safety. The fast expansion of molecular technologies opens new avenues of researchand makes possible the development of innovative pest control technologies, based on the use ofparasitoid-derived molecules and/or on strategies mimicking their effects on insect hosts.