1. The potato crop is affected by a large number of virus diseases resulting in deterioration in the quality of seed stock and low yield of tubers Viral diseases of potato

2. Mild Mosaic (Potato Virus X, PVX) The disease is known to occur world wide where the crop is grown regularly. Symptoms Mild mosaic (patches of normal and light green areas on the leaf) is the general symptom clearly visible on young plants. Leaflets are malformed and death of leaf tip.

3. Mode of spread of Potato Virus X, PVX – Infected tubers Contact between diseased and healthy plants

4. Severe Mosaic (Potato Virus Y, PVY) known to occur throughout the world. Symptoms : The disease induces severe symptoms like crinkling (uneven leaf blade), rugosity (roughness), necrosis (death of tissues) and ultimately leaf dropping. Stunted growth of plants. Lower leaves have black necrotic veins Size and number of tubers are reduced.

5. Mode of spread of Potato Virus Y, PVY Infected tubers Secondary spread through aphid vectors Mode of spread of Potato Virus Y, PVY Infected tubers Secondary spread through aphid vectors

6. Potato Leaf Roll Virus (PLRV) Potato leaf roll is a destructive viral disease of potato, reducing yield and quality of tubers

7. Symptoms Leaflets roll upwards from the margin and progress towards the midribs until the entire lamina is involved Infected plants are stunted and have a light yellow to pale green color. Leaflets are thick, leathery, brittle & rattling sound when disturbed. Few tubers cluster around the stem. Tubers develop necrosis.

8. Mode of spread of Potato Leaf Roll Virus (PLRV) Infected tubers Spread by Aphid vectors Mode of spread of Potato Leaf Roll Virus (PLRV) Infected tubers Spread by Aphid vectors

9. Obtain certified seeds from a reliable source and plant early in the season Rouge out infected plants as soon as detected in the field. Dehulming should be done when aphid population starts building up and then leave the tuber in the soil to mature. Control of aphid vectors: Using systemic insecticides at planting eg. Dimethoate @ 1ml/lit. Management of potato virus diseases