Main Symptoms

Verticillium wilt, like other vascular diseases, is characterised by wilting and / or a distinct yellowing affecting the lower leaves of tobacco plants. The distribution of unilateral symptoms is due to the invasion of xylem vessels by the fungus. Symptoms commonly occur at flowering and during harvest. Later the infected lamina tissues dry up.

A longitudinal cut of the petioles of infected leaves (figure 4) and stem (figure 5) reveals that the vessels have turned yellowish to light brown.

Occasionally lesions can be observed on cured leaves (figure 6).

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.