Tristeza or quick decline: Citrus tristeza virus (CTV)
Symptoms
- Lime is susceptible both as seedling or buddling on any root stock.
- But mandarin and sweet orange seedlings or on rough lemon, trifoliate orange, citrange; Rangpur lime root stocks tolerant; susceptible root stocks are grapefruit and sour orange.
- In sweet orange or mandarin on susceptible root stocks, leaves develop deficiency symptoms and absise.
- Roots decay, twigs die back. Fruit set diminishes; only skeleton remains.
- Fine pitting of inner face of bark of sour orange stock.
- Grapefruit and acid lime are susceptible irrespective of root stock.
- Acid lime leaves show large number of vein flecks (elongated translucent area).
- Tree stunted and dies yield very much reduced. Fruits are small in size. Use of infected bud wood and Toxoptera citricida (aphid) is the important vector.
Management
- For sweet orange and mandarin, avoid susceptible root stocks.
- For acid lime, use seedling preimmunised with mild strain of tristeza.
| Symptoms on leaves |
| Symptoms on fruit |