Main Symptoms

Aphelenchoides ritzemabosi is mainly observed on leaves. It causes large polygonal spots on the leaves which are first light green to yellow, then turn to brown or black. The presence of several spots gives the leaves  the appearance of a checkerboard, hence the origin of the name 'checkered leaf disease' (figures 1 to 3).


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.