European Stone Fruit Yellows Phytoplasma as the Cause of Peach Vein Enlargement and other Yellows and Decline Diseases of Stone Fruits in Southern Italy

In the Campania region of southern Italy, peach trees showing vein enlargement and decline symptoms, as well as apricot and Japanese plum trees showing symptoms similar to that of apricot chlorotic leaf roll and plum leptonecrosis, respectively, were examined for phytoplasma infection using PCR technology. From diseased apricot and plum trees, the target DNA could be amplified with both universal phytoplasma primers and primers that are specific for fruit tree phytoplasmas of the apple proliferation group. However, from samples from diseased peach trees, detectable amplification products were only obtained by nested PCR, in which amplification with universal phytoplasma primers was followed by amplification with primers specific for the apple proliferation group. Following digestion of the amplification products with suitable restriction enzymes, all strains from apricot, plum, and peach showed the same restriction profiles that were identical to those of the European stone fruit yellows phytoplasma, a member of the apple proliferation group.