VIRAL DISEASES OF TULIP/VIRAL DISEASES OF TULIP

VIRAL DISEASES OF TULIP

1. VIRAL DISEASES OF TULIP RAKESH KUMAR MEENA

2. Tulip viruses Common name  Tulip viruses Scientific name  Various Plants affected   Tulipa  spp. (tulips)

3. Main symptoms Streaked flowers, mottled leaves, distorted plant and

4. What are tulip viruses? There are at least 12 viruses that infect  tulips , causing a range of symptoms, which are seen when the tulips have grown leaves in spring and early summer. The six most important are: Tulip breaking virus  (TBV) Arabis mosaic virus  ( ArMV ) Tobacco rattle virus  (TRV) Lily symptomless virus  (LSV) Tobacco necrosis virus  (TNV) Cucumber mosaic virus  (CMV)

5. Symptoms ‘Breaks’ (streaks of a different colour ) in the flowers (TBV) Brown, dead streaks appear in the leaves and stems (TNV) Mottled leaves (TRV, LSV) Sunken brown spots, arcs or rings in the bulbs, such bulbs give rise to stunted and distorted plants (CMV) Plants may be stunted, but otherwise unaffected ( ArMV , LSV)

6. Control Non-chemical control Very little can be done to control viruses in gardens, especially those that are vectored by soil inhabiting organisms such as nematodes or  Olpidium  (a fungal root pathogen). The gardener’s best defence is to ensure that the bulbs come from a reputable source. Affected plants should be destroyed to prevent the spread to other tulips and other plants (some of the viruses discussed above have very wide host ranges among garden plants).

7. Chemical control There are no chemical controls. The use of insecticides to reduce  aphid  transmission is not practical. There are no chemical soil sterilants available to home gardeners for control of nematodes or  Olpidium

8. Biology Plant viruses share many of the characteristics of those that infect animals, though they do not cross infect ( plant viruses only infect plants). Viruses are extremely minute and consist of a protein coat and a core of nucleic acid. They have no means of self-dispersal, but rely on various vectors to transmit them from infected to healthy plants. Once viruses penetrate into the plant cells they take over the cells’ nucleic acid and protein synthesis systems and hijack them to produce more virus. They then require another vector to feed on the infected tissue and carry them to a new host.

9. Vectors CMV, LSV and TBV are vectored by aphids ArMV and TRV are vectored by soil inhabiting nematodes TNV is vectored by the microscopic fungal root pathogen  Olpidium brassicae

10. Tulip breaking virus (TBV) Tulip breaking virus  (TBV) had an important role in ' tulipomania ', which affected the Netherlands in the seventeenth century. The break patterns in affected bulbs were highly prized and sellers commanded huge prices. Unfortunately, the effect was often not stable and affected bulbs did not repeat the patterns reliably in future years. Tulip varieties with these patterns are available today, but the breaks result from stable genetic mutation and not virus infection. 

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