PHYTOPLASMAS IN POME FRUIT TREES: UPDATE OF THEIR PRESENCE AND THEIR VECTORS IN BELGIUM.

Among the numerous diseases that can attack pome fruit trees, apple proliferation and pear decline, both caused by a phytoplasma ('Candidatus Phytoplasma mali' (AP) and 'Ca. P. pyri' (PD), respectively), may result into important losses of quality and quantity of the crop. Until a few years ago, no scientific and reliable data on their presence in Belgium was available and so a 2-year survey was organised to obtain more detailed information on the status of both pathogens. Root and leaf samples collected in commercial orchards were analysed using molecular detection tools and tested positive for both phytoplasmas. Additionally, the presence and infectivity of Psyllidae, vectors of AP and PD, was assessed during this survey but no infected Cacopsylla-species were found. Lab trials revealed its vector capacity at the end of summer and autumn and its migration pattern 80 m in line and 10.5 m across trees in an orchard.