Susceptibility of traditional pear cultivars to fire blight caused by Hungarian Erwinia Amylovora Isolates

Erwinia amylovora (Burrill, Winslow et al.) is one of the most important pathogens of pear and apple and subject to strict quarantine regulations worldwide. Fire blight disease causes serious damages in pear orchards in Hungary. The aim of our experiment was to test the susceptibility of pear cultivars to Hungarian E. amylovora isolates under laboratory conditions. For inoculation test isolates were chosen from different host plants, areas and years. Seven traditional pear cultivars were chosen for testing. Fruit infection was rated according to the diameter of spots produced by the pathogen around the inoculation puncture. Cultivars and isolates were assigned to five susceptibility groups (symptomless, low susceptibility, moderate susceptibility, susceptible and very susceptible). The Hungarian Erwinia amylovora isolates showed different results. We found different susceptibility of traditional pear cultivars. The cultivars Alexander Lucas and Stössel tábornok represented the less susceptible category. Eldorado, Serres Olivér, Diel vajkörte were moderately susceptible. Thus, the most susceptible cultivars were Téli esperes and Drouard elnök. In conclusion, these results can be used for the classification of Erwinia amylovora isolates and in future breeding programmes for resistance