Outbreak of Pseudomonas syringae pv. avellanae on hazelnut in Italy
Symptoms of severe dieback of hazelnut (Corylus avellana) have recently been observed in the Lazio region (Central Italy). The main symptoms are bud failure, leaf chlorosis and rapid withering of the leaves which remain attached on the twigs during summer, dark brown discoloration of bark and cambium, necrosis of the main roots and finally dieback of the plant. During the last five years, this disease has killed more than 1,800 adult trees in one orchard. The causal agent was identified as Pseudomonas syringae pv. avellanae (bacterial canker of hazelnut), which has been described first in Greece. This disease was reported for first time in Italy in the 1990s (RS 509/15, 1991), and these studies have shown that it presents differences in symptomatology with bacterial blight of hazelnut caused by Xanthomonas campestris pv. corylina (EPPO A2 quarantine pest) and the "seccume" disease, which have been respectively reported in Central and Northern Italy.
Sources
Scortichini, M.; Tropiano, F.G. (1994) Severe outbreak of Pseudomonas syringae pv. avellanae on hazelnut in Italy.
Journal of Phytopathology, 140 (1), 65-70.