Greening : Liberobactor asiaticum ( Phloem limited bacteria)
Symptoms
- This disease affects almost all citrus varieties irrespective of root stock.
- Stunting of leaf, sparse foliation, twig die back, poor crop of predominantly greened, worthless fruits.
- Sometimes only a portion of tree is affected.A diversity of foliar chlorosis.
- A type of mottling resembling zinc deficiency often predominates.
- Young leaves appear normal but soon assume on outright position, become leathery and develop prominant veins and dull olive green colour. Green circular dots on leaves.
- Many twigs become upright and produce smaller leaves.
- Fruits small, lopsided with curved columella. The side exposed to direct sunlight develops full orange colour but the other side remain dull olive green.
- Low in juice and soluble solids, high in acid. Worthless either as fresh fruit or for processing. Seeds poorly developed, dark coloured, aborted.
- Infected budwood; psyllid vector- Diaphorina citri
Management
- Control psyllids with insecticides.
- Use pathogen free bud wood for propagation.
- 500 ppm tetracycline spray, requires fortnightly application.
| Greening symptom on leaf |