Occurrence of phytoplasma infection on tomato in Latium, Italy

Tomato plants (Lycopersicon esculentum Mill.) showing leaf yellowing or reddening, proliferation of lateral shoots, hypertrophied calyces, and greening of petals were found in four tomato-growing areas of central Italy during surveys carried out in 1999-2000. The highest disease incidence was recorded in 1999 (78%) and 2000 (82%) near Ronciglione (Viterbo province). The phytoplasmas associated with the disease were detected and characterised using PCR and RFLP. They belonged to 16S rRNA groups I, III, V and XII (sensu Lee et al., 1998. Int. J. Syst. Bacteriol., 48, 1153). Forty-five percent of tomato plants were infected with group I (max. 52% near Frascati and Ronciglione), 31% with group XII (max. 39% near Ronciglione) and 24% with other groups (max. 33% near Tarquinia and 23% near Fondi). Seven percent of tomato plants were infected with both group I and group XII. This is the first report of a group-III and a group-V phytoplasma found in tomato