Aphids cause considerable harm to a variety of crops each year due to damage from feeding and the transmission of viruses. Effective, conventional pesticides that are authorised for use are in continuous decline; simultaneously many of the current biological pesticides fail to meet required efficiency. Increasing demands for improved food security mean that a solution for this problem is needed. Plant surfaces are well known to provide a niche for many bacteria. Some species of bacteria possess pathogenic qualities and are known to kill or incapacitate insects. Therefore there is the potential for the discovery of a direct bacterial application, or the opportunity to manipulate the crop environment in order to encourage the colonisation of these beneficial bacteria. In this project we aim to identify bacteria from plants and screen them for toxicity against aphids and their relatives. Investigations will be carried out into their host specificity, methods of pathogenicity, and potential application methods, with the hope of identifying suitable bacteria for use as a pesticide.