Plant viruses have no specific mechanism for entering the host cell. Cell wall and cuticle are difficult obstacles for them. The animal transmitter does in some cases also act as an intermediate host. This means that some plant viruses are able to multiply within animal tissue. Virus diseases of plants are relatively rare.
Infection is scarcely strong enough to kill the plant.
Among the differences are host range and the degree of virulence . Moreover, viroids were detected. Viroids are small, circular RNA molecules that do not encode proteins themselves. Instead, virions interfere with the transcription of cells due to their similarity with certain areas of recognition of primary transcription products. It seems that viroids prevent the correct cutting out of the introns.