An EPPO code, formerly known as a Bayer code, is an encoded identifier that is used by the European and Mediterranean Plant Protection Organization (EPPO), in a system designed to uniquely identify organisms – namely plants, pests and pathogens – that are important to agriculture and crop protection. EPPO codes are a core component of a database of names, both scientific and vernacular. Although originally started by the Bayer Corporation, the official list of codes is now maintained by EPPO.