Main Symptoms
The symptoms of tobacco mosaic virus (TMV) are quite similar to those caused by CMV (cucumber mosaic virus). Mottling and more or less important "vein banding", on young leaves (figures 1 and 2) are observed. The lamina is sometimes heavily deformed by the presence of blisters. Leaves can curl up and become filiform (figures 3 and 4). Inter-veinal or veinal necrotic lesions are sometimes reported during co-infection with CMV or PVY. When infestation occurs early, plant growth is highly disturbed and often stunted.
The nature and severity of symptoms vary with plant age, type of tobacco grown, or varieties used. Symptoms are more severe on young and growing tissues.
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.