Transmission trials of the fig mosaic disease agent.

Transmission trials of the fig mosaic (FM) agent were carried out using a FM-free colony of Aceria ficus. Portions of mite-infested fig leaves were placed onto leaf pieces of a symptomatic diseased periwinkle, obtained in a previous study. Periwinkle leaf pieces, with potentially infected mites, were then transferred to healthy fig seedlings and some (6%) displayed leaf mosaic a month postinoculation. Subsequently, one of these FM-affected plants was employed as inoculum source for further back-inoculations. Among the fig and periwinkle test plants used, those successfully inoculated by A. ficus resulted to be 98.5% and 33.3%, respectively. RT-PCR showed that the FM donor sources of our experiments contained a single infection of FMV. The virus was also detected in A. ficus individuals that fed on a diseased fig plant. Moreover, electron microscopy revealed the presence of FMV particles in symptomatic fig and periwinkle plants. These new data add further support to the suggestion that FMV could be the real FM etiological agent.