Main Symptoms

 
In general the first symptoms of stolbur appear in August, when tobacco approaches flowering. At this stage of culture, tobacco plants are topped and the axillary buds are inhibited chemically. The first symptom of the disease begins by the yellowing between the veins, a symptom that occurs most frequently on mature or intermediate leaves. Gradually yellowing expands to  the whole plant (figures 1 and 2). In case of dark tobacco, vein and interveinal necrosis are sometimes accompanied by a slight chlorosis of lamina; the resulting syndrome may be confused with that caused by certain necrotic strains of PVY (figure 3). Subsequently the discoloration is so pronounced  that the lamina becomes completely white. This symptom may be the origin of what the old tobacco farmers observed and sometimes referred to as "white feet" (figure 4). This abnormal colour is not the most characteristic of the symptoms, yet it could be the source of much confusion with the symptoms caused by nutritional disorders.
 
The most characteristic symptoms are observed on buds non-inhibited chemically. The young shoots have a reduced growth, much shorter internodes, chlorotic leaves of reduced size with tips tending to curve down. On some plants, the proliferation of numerous short and rigid branches at the apex gives the appearance of a tuft (figures 6 and 7).

When present, the flowers are particularly affected. They are usually sterile and reveal all kinds of anomalies (figure 8), such as small size, enlarged calyx, green colour of the petals and leaf-like appearance ...
 
Harvested leaves are of poor quality, in addition they mould more easily during curing (figure 9) than healthy leaves, their tissues are boardy and poorly coloured.

Some of the information on the worldwide distribution of the disease is obtained from surveys conducted by CORESTA (Cooperation Centre for Scientific Research Relative to Tobacco). The reliability of the information is not confirmed in all countries.