History of a record or The art of assembling distribution lists
In 1938, the Plant Protection Service of Morocco published a leaflet advising growers to steep pea seeds in formalin against pea bacterios is caused by Pseudomonas pisi (EPPO A2 quarantine pest). Whether this was aimed at imported or internally produced seed or whether any copies of this leaflet still exist, is uncertain. The Imperial Mycological Institute in London obtained and abstracted this leaflet in Review of Applied Mycology, and when the Commonwealth Mycological Institute (CMI; as it became) published a distribution map of the disease in the 1950s, the abstract became the basis of a record for Morocco.
When in the 1970s, EPPO first published a data sheet on P. pisi, Morocco was included as 'found, but not established' on the basis of a country report of uncertain foundation. When in the 1980s the data passed into PQR, the EPPO plant quarantine data base, it was accordingly rated 'found but not established'. In the corresponding FAO data base, however, the record appeared rated as 'limited distribution', probably on the basis of the CMI map.
When the EPPO data sheet was revised in the 1990s by an expert author, he rejected the formulation 'found but not established' for several records of the bacterium and preferred 'sporadic outbreaks' which has not quite the same meaning. When the Moroccan Plant Protection Service was again consulted by EPPO to validate this information, it declared that Pseudomonas syringae pv. pisi (as it has now become) does not occur in Morocco.
Finally, when the International Mycological Institute (as it has now become) revised its map in 1993, it retained the 1938 report but added a note 'sporadic', based on 'Quarantine Pests for Europe' (i.e. the revised EPPO data sheet).
The question arises: has Pseudomonas syringae pv. pisi ever occurred in Morocco ? Do all these records from seemingly distinct sources correspond to anything at all ? Or is the whole situation an unintentional fabrication ?
Recently asked to confirm the situation, the Moroccan Plant Protection Service restated that according to surveys carried out in all vegetable growing areas during the last 20 years, symptoms of Pseudomonas syringae pv. pisi have not been found in Morocco, nor do they have any indication of its earlier presence.
We hope that it is relatively unusual for a pest distribution record to have such a history, but suspect that it does happen from time to time. Modern possibilities for transfer of records from one data base to another make it even easier for such situations to arise.
Sources
EPPO Secretariat, Paris (1994-03)