Morphometrics and molecular identification of some Italian populations of Bursaphelenchus eremus Ruhm (Goodey) associated with Quercus spp

Two Italian regions (Lombardy and Tuscany) were surveyed in 2004-2006 to investigate Bursaphelenchus eremus Ruhm (Goodey) associated with broad-leaved trees showing symptoms of decline. Eighteen composite wood samples (from sixty-one Quercus spp. trees) were collected from nine localities, 61 % of the sampled trees contained specimens of B. eremus and 79% the bark beetle Scolytus intricatus Ratzeburg, currently considered this nematode's sole vector insect. In seven wood samples, the collected bark beetles always carried a large number of dauer juveniles beneath the elytra and wings. Six Italian isolates of B. eremus reared in Botrytis cinerea Pets. ex Fr. and three dauer juvenile populations emerged from insects were described in detail using LM and SEM. Comparison between the ITS-PCR of both Italian and German populations of B. eremus is reported together the ITS-RFLP profile of the Italian species. The variability of B. eremus isolates from different bioclimates is discussed and illustrated. Q. suber L. is recorded as new host for B. eremus