Molecular characterization of ‘Candidatus Phytoplasma prunorum’ in Cacopsilla pruni insect vector

Recent investigations on molecular characterization of the ‘Candidatus Phytoplasma prunorum’ (16SrX-B subgroup), causal agent of the European Stone Fruit Yellows (ESFY) syndrome, on the non ribosomal tuf gene resulted in the finding of two groups of isolates, named ‘type a’ and ‘type b’, both with a distinctive geographical distribution in Italian stone fruit growing areas (Ferretti et al., 2007 and 2008). Considering the role of Cacopsylla pruni (Scopoli) in the epidemiological cycle of the disease, the presence of the two groups of isolates has also been investigated in infected psyllid individuals from different Italian areas. Both types have been identified in C. pruni specimens collected on apricot, plum and wild Prunus species, confirming the geographical distribution and the percentages of spread of the two isolates.