Two unusual ilarviruses found on tomatoes in France
In the South of France, in June and July 1997, several growers of tomato (grown for can-processing) observed unusual symptoms. Similar observations were made during the 2 following years. Affected young green fruits showed brown chlorotic rings, becoming sometimes corky lesions, and leaves presented necrotic spots. Studies have showed that 2 unusual ilarviruses might be involved in the disease: tobacco streak ilarvirus and another ilarvirus (TI 1) serologically related to Parietaria mottle ilarvirus. The ilarvirus TI 1 has previously been found on tomatoes showing similar symptoms in Liguria, Italy. Tobacco streak ilarvirus occurs in America, Australia, New Zealand, Japan and Europe. It has been reported on tomato in North America, and also in France on several ornamental plants. Parietaria mottle ilarvirus has only been described in Italy, and was originally found on Parietaria officinalis. This virus has been observed in Liguria, Piemonte, Lazio and Sardegna. The authors felt that the appearance of these tomato ilarviruses is probably not related to tomato seeds, as no seed transmission of ilarviruses is known in tomato, and seed transmission experiments carried out in Italy gave negative results. They thought that transmission is most likely ensured by pollen and thrips vectors.
Sources
Marchoux, G.; Parrella, G.; Gebre-Selassie, K.; Gognalons, P. (1999) Identification de deux ilarvirus sur tomate dans le sud de la France.
Phytoma - La Défense des Végétaux, no. 222, 53-55.