The European ERA-NET SusCrop Project BioProtect aims to contribute to reducing the application of chemical pesticides through the creation of a platform for the development and cost-effective production of nature-friendly dsRNA-based bioprotectants. dsRNA is a natural and environmentally safe molecule that originates from RNA interference (RNAi) pathways involved in gene regulation and pathogen defense. Its exogenous application to plants leads to the activation of RNAi which can be programmed against specific pathogens depending on the designed dsRNA nucleotide sequence. In addition, dsRNA has the potential to trigger pattern-triggered immunity (PTI) thereby reinforcing crop protection through a second host defense pathway. In this project, we use an established dsRNA-production platform in bacteria to produce large amounts of high-quality (hq, fully duplex aligned) long-dsRNA with homology to specific viruses such as TMV or TuMV. After purification, the hq-dsRNAs are formulated using biopolymer nanoparticles with the addition of adjuvants for delivery, stability and enhanced foliar uptake. The antiviral effect triggered upon treatment with formulated and non-formulated hq-dsRNA is tested on N. benthamiana plants and crops such as tomato, cabbage and rapeseed infected with GFP-tagged target viruses. The results indicate that our formulation protects hq-dsRNA against RNAse and that hq-dsRNA-spray application provides local and systemic antiviral protection over several days following treatment. Our current studies focus on the hq-dsRNA fate in treated plants and its effect on viral replication and movement.