RESPONSE OF CENTRAL-EUROPEAN PYRUS GERMPLASM TO NATURAL FIRE BLIGHT INFECTION AND ARTIFICIAL INOCULATION

Of 133 Pyrus accessions (predominantly P. communis L.), collected in C entral Europe and previously rated in the resistant U,S, Dept. of Agri culture (USDA) blight scores 10-6, only 77 (57.0%) remained in these s cores after an additional 5 years of exposure to fire blight [Erwinia amylovora (Burr.) Winsl. et al.], Of these, 24 originated from three s tates in former Yugoslavia. Following several years of severe blight e piphytotics, only 5 (10.4%) of 52 accessions released from quarantine since 1986 and planted at Appalachian Fruit Research Station scored 6 or above, All accessions were highly susceptible to artificial blossom inoculation, and only 10 accessions were at least moderately resistan t to artificial shoot inoculations.