Study of subpopulations of the chestnut blight (Cryphonectria parasitica) fungus in the Carpathian basin

Abstract

During the last few decades destruction of European chestnut (Castanea sativa) populations caused by the chestnut blight fungus (Cryphonectria parasitica) has increased in Central Europe. A total of 650 isolates (from 21 chestnut stands in southern and western parts of Hungary, three stands in Romania and six different sites in the Sub-Carpathion region of the Ukraine) were examined for virulence, classification of vegetative compatibility types (vc types) and for the presence of dsRNA. Up to now 18 vc types have been found in Hungarian chestnut stands, but only one in Romania and one in the Sub-Carpathion region of the Ukraine. Long dsRNA fragments with similar electrophoretic characteristics were found in 36 Hungarian hypovirulent strains. These hypovirulent strains showed reduced virulence in vivo, as well as the in vitro (RADOCZ 1998a).