Bark Canker of Persian Walnut (Juglans regia) Trees Incited by Erwinia nigrifluens in Italy

In autumn J 996. adult Persian walnut (Jug/ans regia L.) trees cultivated in Piedmont (north-west of Italy) showed irregularly shaped cankers along the bark. When the phelloderm was removed. extensive necrosis of the tissues below was observed. A watery. dark-coloured exudate was also frequently observed. Symptoms were present on approximately 10% of 600 trees. Biochemical, nutritional and pathogenicity tests as well as fatty acids analysis of the isolates and type-strain, indicated that ETlIʹinia nigr[ffuells was the causal agent of the disease. This is the first report of this pathogen in Italy