POMACEOUS FRUIT TREE PHYTOPLASMAS AND THEIR POTENTIAL VECTORS IN CROATIA

Surveys of pomaceous fruit trees were carried out in the years 2003 and 2004 in order to determine the current status of ‘Candidatus Phytoplasma pyri’ (pear decline, PD) and ‘Ca. P. mali’ (apple proliferation, AP) in Croatia. PD and AP were in the focus of our interest because they are on the Croatian A2 quarantine list of pests and diseases. Eleven orchards were visually inspected for the symptom presence during summer and autumn. Leaf and twig samples were collected from symptomatic pear and apple trees only. In 2004, potential insects vectors were collected from 5 orchards. Extracted nucleic acids were PCR-tested using primers amplifying 16S rDNA. Digested amplicons showed restriction profiles referable to phytoplasmas belonging to one of the ribosomal subgroups 16SrX-C, 16SrXII-A and 16SrI-B, recently designated as ‘Ca. P. pyri’, ‘Ca. P. solani’ and ‘Ca. P. asteris’, respectively. Mixed infections were detected in one pear and one insect sample. No molecular evidence for the presence of ‘Ca. P. mali’ in Croatia was found within the scope of this research.