Possibile trasmissione di fitoplasmi 16SrX-B mediante Empoasca decedens P. ed Empoasca spp. a Prunus domestica L. ed a Prunus salicina Lindl.

Inside a national research project, coordinated by Istituto Sperimentale per la Frutticoltura of the Italian Council for Research in Agriculture (C.R.A.), Empoasca decedens and Empoasca spp. were reported as possible vector of 16SrX-B phytoplasmas in apricot (Pastore et al., 2004). Since 2002 trials were performed to verify the possibility of these leafhoppers to transmit the same phytoplasmas to European and Japanese plum trees, both sensible to this pathogen. Thirteen samples of nucleic acids extracted as batches from a variable number of Empoasca spp. (from three to twelve) collected between Mai to October 2004, resulted positive to phytoplasma presence. In the same fields 35 living insects of the same species were collected in July 2004, and inserted in Japanese and European plum plants maintained under insect-proof nets. After four and five months from the contact of Empoasca one out of the three European and one out of the four Japanese plum trees, respectively, showed in nested PCR/RFLP the presence of 16SrX-B phytoplasmas. These two plants showed in Spring 2005 drying on all branches and only in Mai new sprouting was visible from basal buds. Studies are in progress to confirm these results and to verify the presence of other possible agents associated with the disease observed.