Main Symptoms

The plants affected by Golovinomyces cichoracearum var. cichoracearum show highly characteristic symptoms, regardless of the plant size and the affected organ. Greyish, white, felt-like powdery patches first appear on the upper leaf surface. They gradually spread and converge to cover eventually the entire lamina. Afterwards the affected tissues show irregular brown lesions resulting from cell death.

The leaves infected with oidium often have thinner tissues and lose their commercial value.

 
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.