CROP |
DISEASES |
SYMPTOMS |
CONTROL |
COCOA
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POD ROT / BLACK POD (PHYTOPHTHORA PALMIVORA) |
The first visible symptom is the appearance of a circular brown spot, which enlarges concentrically, and evenly to cover the whole pod surface. Ultimately the colour of the affected pod becomes dark brown or black. In immature pods, the discolouration spreads internally with rotting of the beans. | Periodically remove and destroy all dried up and infected pods. Spray 1% Bordeaux Mixture with the onset of monsoon and also at frequent intervals. Provide proper drainage and regulate shade to increase aeration |
PHYTOPHTHORA CANKER (PHYTOPHTHORA PALMIVORA) |
The earliest symptom is the appearance of greyish brown water-soaked lesion with dark brown to black margin anywhere on the stem. The wood shows greyish brown discolouration with black streaks. Wilting occurs, when canker girdles the affected stem / branches. | If the disease is detected early, remove and destroy the affected tissues completely and apply Bordeaux paste. Wilted branches should be cut and removed. Since canker mainly develops from pod rot caused by Phytophthora , proper control measures of Pod rot will help in reducing incidence of the disease. | |
PINK DISEASE (CORTICIUM SALMONICOLOR) |
The disease appears as a pinkish powdery coating on the stem of affected plants. The extent to which the leaf may wilt, turn brown and fall depends on the part of the tree, which is affected. The disease mainly affects the forking region and the damage is localized. Splitting of the bark on the affected region is also noticed. | Remove all the infected and dried branches. Apply Bordeaux paste at the fork region and at the cut ends of the twigs and spray with 1% Bordeaux Mixture before the onset of monsoon. Repeat spraying again once or twice during the monsoon season is ideal. | |
LEAF RUST (HEMILEIA VASTATRIX) |
Small pale-yellow spots on the lower surface of infected leaves appear early after the first rains, later turn to orange yellow powdery mass. Infected plant exhibit defoliation, and die-back. | Maintain optimum shade Applications of 0.5% Bordeaux Mixture during April - June (pre - monsoon) and August - October (post - monsoon). |
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BLACK ROT (KOLEROGA NOXIA) |
Blackening and rotting of affected leaves, young twigs and berries. Affected leaves get detached and hang down by means of slimy fungal strands. Defoliation and berry drop occur. |
Remove and burn affected plants. Spray 1% Bordeaux Mixture before the onset of south - west monsoon. |
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BROWN BLIGHT, DIEBACK (COLLETOTRICHUM GLEOSPOROIDES PENZ) |
Yellowing or blighting of any leaf on the green wood, necrosis of nodes and internodes towards the tip. Twigs wilt and defoliate. Floral buds on the infected branches fail to open. |
Spray 0.5% Bordeaux Mixture during Feb/March (Pre-blossom), April - June (premonsoon) and August - October (post- monsoon). |
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FOOT ROT |
All parts of the plant at various stages of growth are susceptible to this disease. There are mainly three types of symptoms which are generally observed, they are leaf rot, collar rot and root rot. |
Spray 1% Bordeaux during May - June and during July - August. Paste the main stem upto 1 to 1½ m above soil level with Bordeaux paste. |
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FUNGAL POLLU |
It attacks leaves, young shoots, spikes and berries. The affected berries show sunken patches, later turn black and dry. |
Spray 1% Bordeaux Mixture, once before flowering starts (June - July) and then at berry formation stage (August - September). |
|
AZHUKAL |
It affects the leaves, tender shoots, panicles and capsules. On the infected leaves, water soaked lesions appear first and rotting and shedding of leaves along the veins occur thereafter. The infected capsules become dull greenish brown and decay. |
Phytosanitation measures. Spray the shoots with 1% Bordeaux Mixture by the commencement of the monsoon and at 30 days interval depending on the intensity of the disease and rainfall. |
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LEAF BLOTCH (PHAEODACTYLIUM ALPINIAE) |
Occurs in heavy rain zones, affected capsules turn brownish black in colour, often rotting extends to tillers and rhizomes also.. |
Do trashing, remove infected and dead plants etc. Spray 1% Bordeaux during May - June (Premonsoon) and at 30 days interval depending on the disease spread. |
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KOLEROGA (MAHALI OR FRUIT ROT) (PHYOPHTHORA ARECAE) |
Water soaked lesions appearing on the nut surface near the perianth spread over the other parts giving the nut a dark green colour. Infected nuts shed without perianth. |
Spray 1% Bordeaux Mixture twice, one before the onset of southwest monsoon and the other, at 45 days interval. If monsoon is prolonged give a third spray. |
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BUD ROT (PHYTOPHTHORA PALMIVORA) |
Affected spindle appears yellow, later changing to brown and finally the whole spindle rots. |
Early removal of the infected tissue and treat the healthy tissues with Bordeaux paste. Drench the crown with 1% Bordeaux mixture as a prophylactic measure. |