Blackleg disease, caused by Pectobacterium atrosepticum, drives economic losses of approximately £50 million per year in the UK alone and this is expected to worsen with climate-driven increases in rainfall and flooding. Bacteriocins (narrow spectrum antimicrobials) offer a targeted low-impact alternative to broad-spectrum chemicals for prophylactic control of P. atrosepticum. We have identified several candidate bacteriocins with strong activity against UK P. atrosepticum isolates, with two candidates from different bacteriocin families showing very effective killing of P. atrosepticum in vitro and ex vivo. We are currently evaluating a multi-bacteriocin formulation to target the seed potato market. To test synergy of killing efficacy, we have combined these two bacteriocins into a formulation and tested their capacity to suppress necrotic lesions in ex vivo tuber assays. Our results show that individual bacteriocin candidates can prevent lesion formation, but when combined act synergistically, meaning combinations are effective at lower concentrations than either individual candidate alone. This demonstrates that our bacteriocin formulation has even greater potential for commercialisation than our individual candidates. To further explore the commercialisation of our formulations, we are studying two aspects: the capacity of the formulations to suppress lesion formation caused by multispecies bacterial communities isolated from affected tubers in the field, and the retention of killing efficacy in the presence of commercially available antifungal treatments. We aim to advance the formulation towards a practical, prophylactic seed-tuber treatment which we can bring to market to increase resilience of potato production and reduce economic loss.