The aim of this work is the preliminary design of a cost-effective, eco-friendly, and reliable injection system for the treatment of the pine and oak processionary moths. The system has been designed to be integrated with a commercial drone, namely the DJI m300 or DJI m350 drones. The proposed system includes a mobile arm enabling the precise injection of a liquid suspension containing dispersed fungal spores directly into the nests, thereby mitigating environmental contamination. The design approach considered the preferred use of commercially available components, where feasible. Computer-Aided Design (CAD) has been used for the realization of the components, coupled with structural analysis through Finite Element Method (FEM) software.