Tobacco bushy top virus (TBTV)

Tobacco bushy top virus (TBTV) belongs to Umbravirus genus (figure 1). It is transmitted by aphids in a persistent manner.
 
 
- Symptoms
 
A clarification and deformation of veins and leaves with mottling, and proliferation of axillary branches that give the plant an appearance of a bush are observed. Affected plants are stunted early during the growing season and produce little or no seeds.
 
 
- Characteristics
 
Two types of particles cause the disease: a mechanically transmissible component responsible for the bushy appearance of plants, and a aphid transmitted component (also responsible for transmission by aphids of a second component) causing vein distortion. This combination of components occurs in Zimbabwe, South Africa, Tanzania, Malawi and perhaps Pakistan and Thailand. The virus  survives on other Solanaceae. In order to reduce the incidence of TBTV it is recommended to plant tobacco early, use aphicide treatments on soil and / or plants, and remove virus reservoir plants.