ABSTRACT
The ilarvirus group was organized by the ICTV in 1976; the group name is derived from isometric labile ring spot. Viruses in the group have been placed in subgroups based on serological relationships. Ilarviruses, bromoviruses, cucumoviruses, and alfalfa mosaic virus have some properties which are similar, such as having three ssRNA molecules encapsidated in isometric or bacilliform particles. Cytological studies of ilarvirus infections have been very limited, and they do not allow determinations of distinctiveness of inclusion types. Citrus infectious variegation ilarvirus also induces this type of inclusion. Structures described as funnel shaped appeared to develop from the plasma membrane near plasmodesmata. These structures, containing one or two rows of virus particles, were not encased in cell wall materials. They appear to be inclusions unique to TSV infections. TSV has been reported in natural infections of 62 species in 46 genera of 19 families, including 15 species in 10 genera of the Leguminosae.
