Some other viruses, not found in France

Other viruses than those presented in the previous sections induce leaf discoloration on tobacco, but have not been, to our knowledge, observed in France to date. Some of them are described here, with symptoms and pictures. Please, see the facts sheets of pests concerned:
 
- Tomato spotted wilt virus (TSWV) is a virus transmitted by thrips, such as Thrips tabaci or Frankliniella occidentalis. This virus induces necrotic, occasionally concentric spots on young leaves whereas the stem curves  and certain leaves are affected unilaterally. A partial necrosis of the lamina, longitudinal necrotic lesions on the stem as well as wilting and drying of leaves (figures 1 to 4) are observed (tomato spotted wilt virus).
 
- Tobacco etch virus (TEV) is a potyvirus like PVY. A "vein clearing" and mottling is observed on young leaves, necrotic arabesques, chlorotic interveinal spots becoming necrotic, and vein necrosis of lower leaves have  also been reported (figure 5). Plant stunting is also observed. Several species of aphids (Myzus persicae, Myzus nicotianae, Macrosiphum spp ....) transmit the virus in a non-persistent manner (tobacco etch virus).
 
These two viruses,TSWV and TEV, have sometimes been reported or suspected in France, but not detected in examined samples of tobacco leaf.
 
- Tobacco vein mottling virus (TVMV) belongs to the genus Potyvirus. Its symptoms are very discreet, with vein clearing, and dark green irregular bands along the veins ("vein mottling", figure 6). Several species of aphids transmit the virus in a non-persistent manner (tobacco vein mottling virus). Moreover, this virus can form a viral complex with TEV, often found in Kentucky on Burley tobacco (figure 7)
 
- Tobacco vein banding mosaic virus (TVBMV). This potyvirus induces many dark green tissue bands along the veins ("vein banding"), with small white to brown spots on the upper leaf surface of younger leaves, quite similar to those caused by "weather fleck". As the previous virus, its transmission is done by several aphid species in a non-persistent manner;
 
- Another Potyvirus, the Chilli veinal mottle virus (ChiVMV) occurs on tobacco in Thailand, sometimes in complex with CMV, and cause symptoms quite comparable to those caused by PVY;
 
- Potato virus X (PVX) is classified in the genus Potexvirus. When plants are infected, dark green tissue bands along the veins ("vein banding"), ring spot, and light grey necrotic spots appear. More damage is occasionally observed when a co-infection with PVY occurs. Mechanical transmission of PVX, by tools, clothing, etc. is very easy.
 
- Peanut stunt virus ( PSV) is a Cucumovirus (family Bromoviridae). Its symptoms are different for different types of tobacco. There are large chlorotic patches on young leaves with yellowing and chlorotic rings on older leaves, or mosaic-like symptoms similar to those induced by TMV or CMV, with ring spots. Several species of aphids transmit the virus in a non-persistent manner.

 
For more details on these viruses, please see the corresponding topics of Other parasitic tobacco viruses.