New results concerning the plum pox virus epidemiology and resistance of plum cultivars, hybrids and rootstocks

Our recent results on the plum pox virus (PPV) epidemiology show that PPV s preads very rapidly in plum tree plantations in the contaminated areas. A c learing of the PPV-infected trees reduces significantly the spread of the v irus but does not eliminate the disease. Some plum tree cultivars, hybrids and rootstocks (Scoldus, Alina, Cristi, BN 1/8F1, BN 2Gr. etc) showing fiel d resistance could not be infected with PPV by natural way. However, they c ould be infected with PPV by artificial inoculation except for the plum tre e cv. Local of Dragasani and the BN 4Kr myrobalan, which proved to be immun e to PPV. PPV was not transmitted through seeds in plum tree and myrobalan in the nursery. The Hyalopterus pruni aphids were found PPV-positive by an enzyme-linked immunosorbent assay (ELISA).