PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY, SRI PARAMAKALYANI COLLEGE, ALWARKURUCHI -627 412

2. Cont…
 TOBACCO MOSAIC VIRUS
 TOMATO YELLOW LEAF CURL VIRUS
 COTTON LEAF CURL VIRUS
 TOBACCO STREAK VIRUS
 SUGARCANE MOSAIC VIRUS
 TUNGRO VIRUS

3. CLASSIFICATION
Classification:
 Family - virgaviridae
 Genus - Tobamovirus
 Species – Tobacco mosaic virus

4. Satureure

6. TOBACCO MOSAIC VIRUS
 Tobacco mosaic virus Was discoveredIn 1892 by Dimitry lvanowSy from the Tobacco
plant.
 Vires infect healthy plants through vectors like ophids, locusts etc.
 The first visible symptom of TMV is discoloration of leaf colour along the veins and show
typical yellow and green mottling which is the mosaicsymptom.
 The downward curling and distortion of young apical leaves occurs, plant becomes
stunted and yieldis affected.
 Electron microscopic studies have vevealedthat TMV is rood shaped helical virus.
 Measures about × 150 m with a molecular weight of 39 × 106 Daltons.

7.  The virion is made up of constituents a protein coat capsid and a core callednucleic
acid.
 The protein coat is made up of approximately 2130 identical protein subunits called
capsomeres .
 They are present around a central single stranded RNA molecule.
 The genetic informationnessary for the formation of a complete TMV particle is contained
in its RNA .
 The RNA consists of 6500 ., nucleotides.

8. Prevention
 Plant virus-resistant varieties in your garden. Resistant varieties of tomatoes have yet to be
developed for cucumber mosaic virus, but tomatoes that are resistant to tobacco mosaic virus
may have some slight resistance to cucumber mosaic virus as well.
 Mosaic viruses are mostly spread by insects, especially aphids and leafhoppers. You can try
covering your plants with a floating row cover or aluminum foil mulches to prevent these
insects from infecting your plants. Look at our other tips for controlling aphids.
 Control your weeds. Some types may serve as hosts for the disease, and when aphids and
other insects feed on these plants, they will spread the viruses to your garden plants.
 To avoid seed-borne mosaic viruses, soak seeds of susceptible plants in a 10% bleach solution
before planting

9. Control
 Remove all infected plants and destroy them. Do NOT put them in the compost pile, as the
virus may persist in infected plant matter. Burn infected plants or throw them out with
the garbage.
 Monitor the rest of your plants closely, especially those that were located near
infected plants.
 Disinfect gardening tools after every use. Keep a bottle of a weak bleach solution or other
antiviral disinfectant to wipe your tools down with.

10. CLASSIFICATION
 Family – Geminiviridae
 Genus – Begomovirus
 Species – Tomato yellow leaf curl vires

11. IN FECTED PLANT

12. TOMATO YELLOW LEAF CURL VIRUS
 The leaf curl is characterisedby severe stunting of the plants with downward rolling and
crinkling of the leaves.
 Paritial or complete show chlorosis the older curled leaves become leathery and brittle.
 Plants are stunted due to shortening of the internodes.
 Diseasedplants look pale and produce more lateral branches resulting in bushy growth.
 The disease is transmittedby the whitefly, Bemisiatabaci.

13. Control
 Use a neonicotinoid insecticide, such as dinotefuran (Venom) imidacloprid
(AdmirePro, Alias, Nuprid, Widow, and others) or thiamethoxam (Platinum),
as a soil application or through the drip irrigation system at transplanting of
tomatoes or peppers.

14. Prevention
 Maintain good weed control in the field and surrounding
areas. Prevent the spread of any whiteflies to healthy plants.
Tomato and pepper fields should be cleaned up immediately
after harvest. Also destroy crop residues of melons and
cotton immediately after harvest to reduce whitefly
migration.

15. COTTON LEAF CURL VIRUS

16. In fected
plant

17. Healthy Leaf Infected Leaf

18. Leaf enation

20. SYSTEMATIC POSITION OF LEAF CURL VIRUS

21. Control

23. Prevention

26. SYSTEMATIC POSITION OF TSV

27. TOBACCO STREAK VIRUS

28. Control

29. Prevention

30. SUGARCANE MOSAIC VIRUS

31. SYSTEMATIC POSITION

33. Prevention

35. Control
 To minimize spread of sugarcane mosaic virus all equipment used
should be sanitized. Fungicides and other pesticides have been shown
to be ineffective when dealing with viral disease. The best way to deal
with a viral disease is through plant host resistance.

36. TUNGRO VIRUS
 Stunting and reduced tillering.
 Leaves become yellow or orange yellow.
 From tip to down with necrotic lesion without wavy margins
 Delayed flowering panicles small and not completelyexerted.
 Most panicles sterile or partially filledgrains.
 It has two forms rice tungro Bacillform virus and Rice tungro spherical vires.

39. Prevention
 Set up light traps to monitoring and attract vectors.
 Destruction of weed hosts on bunds.
 Grow tolerant varieties like co,45 co 48,.. Surekha , vikramarya, Bharani IR 36.
 In epidemic areas follow ratation with pulses or oil seeds.
 Use carbofuran 2 kg/20 cent of nursery area.
 GLH can be controlledby spraying phophomidan or Lmidachloprid.

40. Control
 Application of insecticides.
 Use of resistant varieties.
 Removal of infectedplants from the field.