Transmission of fig leaf mottle-associated virus 1 by Ceroplastes rusci

Viruses associated with fig mosaic disease are disseminated by grafting but not by seed and some of them are transmitted by Aceria ficus. To investigate the role of Ceroplastes rusci in the transmission of fig mosaic disease agents, first nymphs were collected from fig plants exhibiting typical mosaic symptoms in a fig orchard and transferred to fig seedlings in the laboratory. After 20 days, leaf curling, vein clearing and leaf chlorotic mottling symptoms were observed on the leaves of seedlings exposed to C. rusci, but not on control seedlings even after six months. Leaves of donor plants were infected with fig leaf mottle-associated virus 1 (FLMaV-1), fig mosaic virus and fig mosaic-associated virus 1, as shown by RT-PCR with specific primers, but only FLMaV-1 was detected in symptomatic fig seedlings following exposure to C. rusci. Sequencing revealed that FLMaV-1 isolates obtained from both donor plants and recipient seedlings were identical and closely related to an Italian FLMaV-1 isolate. This is the first report of FLMaV-1 transmission by C. rusci.