Old and new viruses of lily in Italy

An epidemiological survey has been carried out in Italy from 1997 to 1999 in order to identify the most frequently occurring viruses in lily (Lilium spp.). In 1997 one hundred bulbs cv. Benino and 60 cv. Polyanna (Asiatic hybrid group), planted in an insect-proof greenhouse and tested by mechanical inoculations on herbaceous plants, leaf-dip, DAS- and PAS-ELISA, ISEM and GLAD, were infected by lily symptomless carlavirus (LSV) (100%) and cucumber mosaic cucumovirus (CMV) (44%). In one of CMV infected "Polyanna" plants, tomato ring spot nepovirus (ToRSV) was also detected. In 1998, two hundred and nine lily bulbs belonging to 12 clones were singly tested. One hundred percent of them were infected again by LSV and 54% also by CMV. In the same year, 12 lily bulbs cv. Casablanca (Oriental hybrid group) tested were all infected by LSV and one also by strawberry latent ringspot nepovirus (SLRSV). In 1999, in a cultivation located in Lazio region (central Italy) some lilies of a pink color cultivar, showing colour-breaking on the petals, were infected by a potyvirus-like isolate serologically only related to turnip mosaic potyvirus (TuMV). This survey confirms the high diffusion of LSV and CMV, which actually represent the most dangerous viruses for Italian lily cut flower production. The nepoviruses ToRSV and SLRSV were never found before in our country. The "new" potyvirus associated with flower colour-breaking could be similar to tulip top-breaking potyvirus (TTBV) which is closely related to TuMV.