Mosaic mottling of leaves and stunting of plants are the characteristic symptoms of potato virus Y Mosaic symptoms are mild in early stages but later become severe.
Infected leaves are deformed, small and leathery. Very few fruits are produced on infected plants.
The important symptom produced by tobacco mosaic virus is conspicuous mottling of leaves.
Leaves also develop blisters in advanced cases. Severely infected leaves become small and misshapen. Plants infected early remain stunted.
PVY is easily sap transmitted.
It is transmitted in the field through aphids, Aphis gossypii and Myzus persicae and perpetuates on weed hosts like Solanum nigrum and S.xanthocarpum.
TMV is transmitted by sap, contaminated implements and clothes, soil debris and hands of labour.
It can perpetuate on many cultivated plants like cucurbits, legumes, pepper, tobacco, tomato and weed hosts. The virus survives in plant debris in soil.