THE EXPERIENCE IN ESTABLISHMENT AND MAINTENANCE OF PLUM POX VIRUS-FREE SCION ORCHARDS IN RIMSA TROYAN

During the period of 23 years up to now, in RIMSA in Troyan, experiments for establishment and maintenance of two scion orchards of plums were carried out. The first orchard was established in 1988, with 318 trees of plum cultivars basic for the country. For a 15-years period of usage (till 2003), 17 mother trees infected with Plum pox virus (PPV) were registered and eradicated.
In 2001, the second scion orchard was established, in the area of Boyadjievo, with 52 cultivars of 7 fruit species, including 11 plum cultivars, presented by 476 mother trees. Up to this moment 12 trees (2.52%) infected with PPV in the orchards were registered and eradicated.
The experiment shows us that the maintenance of such scion orchards is possible if some minimum conditions are followed, such as: space isolation of the orchard from existing plantations and wild species of genus Prunus - 800 m; grass regeneration of the soil surface with cereal grasses; vector chemical control; permanent observation for symptoms appearance; annual testing of at least 1/3 rate of the mother trees serologically by double antibody sandwich (DAS)-ELISA.