Reaction of some plum cultivars to sharka virus (Plum pox virus, PPV-M strain)

The reactions of 63 plum cultivars and 10 elites of Prunus x domestica L. was studied under the conditions of a natural infection with the plum pox virus. The plantation was created in the period from 1973 to 1988. Since 1989 regular observations have been performed to establish the occurrence and spread of the plum pox disease using an original practical scale. The PPV-M agent was detected by DAS ELISA and DASI ELISA tests. Depending on the maximum marks obtained by the end of the period and their comparison with the results from the inummoenzyme tests, the cultivars were divided into five groups: high susceptible, susceptible, tolerant, resistant under field conditions and others whose viral status is to be investigated additionally.