Description on general symptoms produced by plant pathogenic viruses

1. Symptoms of plant viral
diseases
N. H. SHANKAR REDDY
Ph.D., Plant Pathology
Annamalai University

2. • Identification of virus
• Name of the disease

3. Chlorosis
Symptoms of chlorosis usually start as interveinal chlorosis and spread through the
entire leaf lamina
• Eg - Wheat yellow leaf, Potato yellow dwarf, Barley yellow dwarf

4. Epinasty
Downward twisting of leaves
Eg - Pea mosaic, Potato super wild mosaic

5. Enation
Abnormal small hair like out growth from the surface of a stem or leaf associated
with mosaic symptoms.
• Eg – Tobacco enation

6. Etch (etching)
• Affected leaves and fruits become stunted. Pale colour discolouration can also be observed
• eg - TSWV

7. Leaf curling
Distortion of leaves resulting from unequal growth or expression of leaf tissues and
folding of leaf tissues backward.
Eg – Papaya leaf curl virus

8. Leaf rolling
Leaves roll up and become chlorotic or discolouring of leaves
• Eg – Potato leaf roll virus

9. Mosaic
Mixed light green and yellow patches on the leaves. The infected areas are usually
pale green or chlorotic due to loss or reduced production of chlorophyll
Eg – TMV (Tobacco mosaic virus), Tomato mosaic, Cucumber mosaic

10. Mottle
It is a type of mosaic with, yellowish spots, irregular marks, blotches or patches of
various shades in leaves of plants
Eg – Pepper mild mottle virus

11. Necrosis
Degeneration of protoplast followed by death of tissues or organs
(Localized genera death and disintegration of plant cells and plant parts, usually
resulting in tissue turning brown or black due to oxidation of phenolics)
Eg - Cabbage leaf necrosis caused by Turnip mosaic virus, Oat necrotic mottle

12. Phyllody
Floral parts are transformed into green leafy like structure followed by vein clearing,
in severe cases entire inflorescence is replaced by short twisted leaves and looks like
to witches broom
• Eg – Sesame phyllody

13. Proliferations
Rapid and repeated production/ development of young cells, tissues or organs which
grown beyond their original limit
• Eg – Apple proliferation

14. Ringspot
Prominent mosaic and chlorosis on leaf lamina and distortion of young leaves,
results in the development of shoestring appearance.
Eg - Papaya ringspot virus

15. Stunting
Retardation of growth, resulting in stunting of plants
Eg- Banana bunchy top virus

16. Stripe
Discolouration of leaves and reduced the growth of stem and leaves
• Eg – Barley leaf stripe virus

17. Stunting/ dwarfing
Growth may be reduced evenly throughout the plant or the stunting may be confined
to certain parts or organs of the plant, root growth may also be stunted
Eg - Pea stunt disease caused by Red clover vein mosaic virus,
Rice dwarf disease; Peanut stunt disease

18. Tumours/ galls
Characteristic tumour-like outgrowths are formed on the leaves and roots, wart-like
outgrowths are produced on the lower surface of leaves due to abnormal proliferation
of the underlying phloem tissues
Eg - Wound tumour virus, sugarcane Fiji virus

19. Vein clearing
Yellowing of veins and veinlet’s, vein becomes translucent, while the interveinal areas
remain green.
Eg - Bhendi vein clearing
Lettuce vein clearing

20. Vein banding
In the infected plant, the area adjacent to the veins of the leaf remain green, in contrast to
the remaining areas of the leaf, which may be chlorotic.
Eg - Chilli vein banding caused by Tobacco etch virus.

21. Yellowing
Uniform chlorosis of the leaves
Eg - Rice yellows
Yellows (Chlorosis)– Yellows of leaves and stunting of plant
• Eg – Sugar beet yellows virus, Coconut lethal yellowing

22. Yellow mosaic
The leaves of infected plants develop more of irregular yellow
patches than the green portion and the infected plants are stunted.
Eg - Turnip yellow mosaic
Clover yellow mosaic
Bean yellow mosaic and Barley yellow mosaic

23. Video available at you tube
Channel – Geeky Researcher