Sequivirus is a genus of viruses in the order Picornavirales, in the family Secoviridae. Plants serve as natural hosts. There are currently three species in this genus including the type species Parsnip yellow fleck virus. Diseases associated with this genus include: PYFV: vein-yellowing, yellow flecks and yellow/green mosaic symptoms in parsnip, and ‘yellow net', followed by yellow spots and leaf distortion in celery.
Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. The virus exits the host cell by tubule-guided viral movement. Plants serve as the natural host. The virus is transmitted via a vector (insects (aphids). Transmission routes are vector and mechanical.