Main Symptoms

The presence of Ditylenchus dipsaci in tobacco can be observed in several plant parts :
- In the new plant growth. Newly developed leaves grow asymetrically and they are "twisted" (figure 1). If the weather is not favourable for tobacco growth the development of young plants can be slowed or stopped, resulting in stunted plants;
- At the collar level cortical tissue is swollen and distorted. Thus the cortical tissue can decompose and disappear, leaving the vascular system bare. The affected tobacco plants are easily blown by the wind, after the breakage of the stems at the distorted collar level. Late outbreaks are less damaging than the early ones.


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.