The Close Relationship between the Careless Production of New Apricot Trees and the Spread of a Causal Agent of Bacterial Canker in Apricot Orchards

Bacterial canker and the premature death of young stone fruit trees, caused by different members of the Pseudomonas syringae ( Ps ) complex, affects commercially grown apricot orchards. Altogether, 70% of samples of mother apricot tree scion varieties ( Prunus armeniaca L.) from different European localities consisted of Pseudomonas strains which are highly pathogenic to detached apricot twigs in the pathogenicity test. These strains were attributed to phylogroup PG02 and PG03, and rpoD sequencing confirmed a similarity to strains of Pseudomonas syringae pv. syringae and Pseudomonas amygdali pv. morsprunorum race 1 known to be pathogenic to apricot, respectively.