75 PVY isolates from a survey of burley tobacco fields in Campania (South Italy) were characterized by laboratory tests and inoculation on differential host species and cultivars of flue-cured and Burley tobacco. No difference in morphology, physical properties, serological tests or behaviour on host species other than tobacco was found among the isolates. On flue-cured tobacco three types could be detected according to the symptoms shown by cultivars resistant or susceptible to the root-knot nematode Meloidogyne incognita CHIT : 1) veinclearing, veinal necrosis, and bronzing on both; 2) severe veinal necrosis with rolling downward of the leaf midrib and plant death at temperatures below 24.degree.C on resistant, and veinbanding on susceptible; 3) leaf curling and veinbanding on both. These strains were found on 34, 2 and 39 isolates respectively. Burley cultivars showed veinclearing, necrotic veinal necrosis, and bronzing with type 1, and leaf curling, blistering, and veinbanding with types 2 and 3. Type 1 produced veinclearing, veinal necrosis, and bronzing on cvs Virgin A Mutant, Virginia Aurea, and Virginia Vinica, previously reported as immune to necrotic PVY.