Viruses of pelargonium in Italy

Plants of Pelargonium zonale and P. peltatum infected with viruses other than those reported in the literature were found in northern Italy. Five of these unidentified isolates were studied. All were sap-transmissible to indicator plants, especially Chenopodium quinoa. The following viruses were identified and partially characterized: cherry leafroll nepovirus (CLRV), serologically distinct from a typical European isolate from cherry; lilac chlorotic leafspot capillovirus (LCLV), serologically related to both the type and the iris strains; tobacco necrosis necrovirus (TNV), systemic in C. amaranticolor and C. quinoa, serologically differing from serotypes A and D, and two isolates serologically closely related, (coded Gr 25 and Gr 57), in dsRNA patterns resembling pelargonium ringspot (PeRSV), a supposed carmovirus, but differing from carnation mottle and pelargonium flower-break carmoviruses. Evidence for a distant serological relationship between Gr 57 and PeRSV was obtained in agar gel diffusion tests, but this was not confirmed by other tests. Healthy P. zonale seedlings sap inoculated with Gr 25 and Gr 57 developed ringspots and vein banding; the CLRV and TNV isolates gave latent infection, and the LCLV isolate has so far caused no infection.