A New Virus Disease of the Tobacco Plant

Abstract

IN recent years investigators have recognised many virus diseases of the tobacco plant, all, however, producing chlorosis or necrosis of the leaves. I have investigated at Amani a disease of different manifestation, which I believe to be caused by a virus. The characteristic symptom of this disease is leafy outgrowths from the veins on the lower surface of the leaves, sometimes up to a centimetre wide, but usually amounting to no more than a dark green thickening of sections of the veins. Combined with this feature is a stunting of the whole plant and twisting and curling of the leaves. The manifestation of the disease varies greatly according to environmental conditions and the variety of tobacco concerned. I have, however, never observed chlorosis or necrosis in affected plants.