Mosaic of Tomatoes

a virus disease of tomatoes manifested by the formation of brown necrotic spots and stripes on the leaves, stems, and fruits. Simple mosaic of tomatoes is caused by the tobacco-mosaic virus (Nicotina virus 1); complex mosaic, which is less common, is caused by the tobacco-mosaic virus combined with X and Y viruses of potato mosaic or with the virus of cucumber mosaic (Cucumis virus 1). The incubation period of the disease is seven to 14 days. Severe infection causes the leaves to die and the fruits to become deformed; the taste quality is also lowered. The disease is especially harmful in hotbeds.

Control measures include disinfection of seeds, soil, and hotbed materials; also maintenance of optimum temperature, humidity, and illumination in hothouses.