Horticultural crops :: Plantation crops:: Coconut
| BUD ROT: Phytophthora palmivora |
Symptom:
- Palms of all age susceptible, but normally young palms are more susceptible, particularly during monsoon.
- In seedlings, the earlier symptom is the yellowing of one or two younger leaves. Basal tissues of the leaf rots quickly and can be easily pulled out from the crown.
- In the later stages the spindle withers and drops down.
- The tender leaf base and soft tissues of the crown rot into a slimy mass of decayed material emitting foul smell.
- Ultimately the entire crown falls down and the palm dies
- In adult palms, the first visible symptom is the colour change of the spear, which becomes pale and breaks at the base and hangs down. The rotting slowly progresses downwards, finally affecting the meristem and killing the palms. This is accompanied by drooping of successive leaves. Even then, nuts that are retained on the palm may grow to maturity.
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| Pale leaf |
Leaf rot |
Rooting of basal tissue |
Drooping |
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Cultural method
- Provide adequate drainage in gardens.
- Adopt proper spacing and avoid over crowding in bud rot prone gardens.
Chemical method
- Remove all the affected tissue of the crown region and drenching the crown with Copper oxychloride 0.25%. Apply Bordeaux paste and protect it from rain till normal shoot emerges. (Dissolve 100 gm of copper sulphate and 100 gm of quick lime each in 500ml. water separately and mix to form 1 litre of Bordeaux paste).
- Spray 0.25% Copper oxychloride or 1 % Bordeaux mixture on the crown of the neighbouring palms as a prophylactic measure before the onset of monsoon. Palms that are sensitive (Dwarf palms) to copper containing fungicides can be protected by mancozeb. Small, perforated sachets containing 2 g of mancozeb may be tied to the top of leaf axil. When it rains, a small quantity of the fungicide is released from the sachets to the leaf base, thus protecting the palm.
- The infected tissues from the crown region should be removed and dressed with Bordeaux paste sprayed with 1% Bordeaux mixture as pre-monsoon spray (May and September).
- Leaf axil filling with Sevidol 8G, 25 g mixed with 200g sand is recommended to manage red palm weevil infestation of affected palms.
- Spray with Copper oxychloride 0.25% after the onset of Monsoon.
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