Occurrence of Pseudomonas avellanae (Psallidas) Janse et al. and related pseudomonads on wild Corylus avellana trees and genetic relationships with strains isolated from cultivated hazelnuts

Surveys in submediterranean forests of central Italy were carried out during 0885 87 to verify the possible presence of bacterial canker caused by Pseudomonas avellanae in wild hazelnut trees "Corylus avellana L[#[ Wilted twigs were noticed several times especially in summer[ In other cases\ wild C[ avellana trees growing near to hazelnut orchards appeared completely wilted[ Isolates that were pathogenic to C[ avellana\ showing a di}erent degree of virulence\ were obtained in both situations[ Biochemicalphysiological and nutritional tests as well as the com! parison of whole!cell protein pro_les\ revealed the pres! ence of 05 isolates identical to P[ avellanae reference strains that had previously been isolated in the same area and _ve deviating isolates[ Repetitive!PCR genomic _ngerprinting performed by using BOX "Box elements#ERIC "Enterobacterial Repetitive Interkingdom Con! sensus# and REP "Repetitive Extragenic Palindromic# primer sets and analysed by means of UPGMA\ revealed the existence of two main groups of pseudomonads pathogenic to C[ avellana[ Group A includes P[ avellanae strains isolated in northern Greece and central Italy as well as the isolates obtained from the wild C[ avellana trees grown near the cultivated hazelnut orchards[ Group B includes strains previously isolated in northern\ sou! thern and other areas of central Italy as well as the isolates obtained from C[ avellana wild trees showing twig dieback[ Control measures should be taken to avoid the spread of bacterial canker of hazelnut in the forests of central Italy