Report of phytoplasma infection in European plums in Italy
In Italy, in the western part of the Trentino region, a decline has been observed for several years in a European plum cultivar (Prunus domestica, cv. Susina di Dro). Symptoms are similar to those reported for Japanese plum leptonecrosis phytoplasma on Japanese plum (Prunus salicina). Symptoms are characterized by an upward rolling of the leaves, which also became bronze-reddish, thick and brittle, a growth of normally dormant axillary buds, an off-season growth during November-January and a phloem necrosis. Phytoplasmas were constantly detected by the DAPI technique and by PCR amplification of DNA in symptomatic trees. So far, phytoplasma infections of European plums had only been reported from France in limited areas. Therefore, the authors noted that this is the first report of a widespread phytoplasma disease in a cultivar of European plum. In addition, RFLP analysis with restriction endonuclease revealed a pattern identical to that of phytoplasmas from Japanese plum affected by plum leptonecrosis and apricots affected by apricot chlorotic leafroll (EPPO A2 quarantine pest). The authors felt that their results are a further indication that the phytoplasmas present in Prunus species in Europe are closely related and belong to the same cluster (apple proliferation cluster). They felt that this is a further justification for grouping all phytoplasmas causing diseases of European stone fruit under the name of European stone fruit yellows (see EPPO RS 96/003).
Sources
Poggi Pollini, C.; Bissani, R.; Giunchedi, L.; Vindimian, E. (1995) Occurrence of phytoplasma infection in European plums (Prunus domestica).
Journal of Phytopathology, 143(11-12), 701-703.