EPPO Plant Protection Thesaurus (EPPT) is available from the EPPO website
The EPPO Plant Protection Thesaurus (EPPT) is a database of plant and pest names. For more than 50,000 organisms important in agriculture and crop protection, it provides preferred scientific names, synonyms, common names in different languages, EPPO codes, and taxonomic relationships. Previously, EPPT had to be purchased on a CD-Rom from the EPPO Secretariat but from June 2007 the whole database can be freely accessed from the EPPO website at the following address: http://eppt.eppo.org
As mentioned above, EPPT contains the EPPO codes (formerly the BAYER codes) which can be used for computing purposes. In this system, a unique letter code is attributed to each biological entity. In the near future, users who wish to include the EPPO codes into their own computer systems will be able to obtain licenses to download codes directly from the online database. In addition, licensed users will also have a privileged access to request new codes. But for the moment these features are still under development.
Sources
EPPO Secretariat, 2007-06.