ABSTRACT
The first grouping of viruses which is now classified as the carlaviruses was that of Brandes and Wetter. Carlavirus particles are 600 to 700 nm in length, are slightly flexuous, and contain ca. 6% ssRNA with a molecular weight of ca. 2.7 × 106. Some carlaviruses are whitefly transmitted. Viruses within other groups are also known to be transmitted by different types of vectors. Carlavirus-induced banded-body inclusions are less complex and narrower than those induced by potexviruses. Closterovirus-induced banded-body inclusions occur primarily in the phloem, while those controlled by carlaviruses do not. A few potyviruses induce small cytoplasmic banded-body inclusions; however, all potyviruses induce cylindrical cytoplasmic inclusions, while carlaviruses do not. The particle aggregate inclusions together with the banded-body inclusions and irregularly shaped inclusions are diagnostic for carlavirus infections at the group level.
