(a) Discuss the production of cocoa (Theobroma cacao) under the following headings: (a) land preparation; [2 marks]
(b) climatic requirements; [3 marks]
(c) planting; [6 marks]
(d) one disease. [5 marks]
Explanation
Production of cocoa (Theobroma cacao)
(a) Land preparation
-Select well-drained deep soil, heavy clay-loam/loam with slightly acidic or neutral pH.
- Keep the area protected from strong winds.
-Clear the area manually or mechanically.
- Avoid clean-clearing/some forest/big trees may be left to provide shade for seedlings.
-Leave some plant refuse behind to provide mulch and reduce evaporation.
(b) Climatic requirements
-Cocoa s a humid tropical crop
- Grows best in areas with 1140 - 2000 mm annual rainfall, well distributed most of the year.
-Needs constant supply of moisture.
-Should be protected from strong wind
-Temperature requirement not below 17°C
(c) Planting
-Cocoa trees are usually raised from nurseries. '
-Seeds to be planted in the nurseries must be selected from those freshly harvested pods because seed viability reduces rapidly if kept for long time.
Seeds are planted in small baskets filled with good loamy soil and should be well-watered but not water-logged.
- Keep the baskets with the seeds under shades protected from strong winds.
-Can use plastic buckets instead of basket though their bases should be cut and sides slited open when transplanting.
- Transplanting is ready within 5-9 months after sowing the seeds.
- Planting is usually done at the beginning of the rainy season.
-Spacing is usually 3m x 3m, though this varies with 3 the cultivar.
-When transplaning, dig sufficiently deep and large holes to accommodate the whole ball of earth from basket or plastic bucket.
-After removing the basket/plastic pot, put good loamy soil around the seedling.
- Apply mulch around the seedling.
-Water and provide shades.
- Cocoa seeds may also be planted directly in the field, using initial spacing of 1m x 1m later thinned down to 2m x 2m; and finally 3m.
(d) Diseases of cocoa:
Swollen shoot disease
- Caused by virus.
-Transmitted by mealybugs.
- Cause leaf distortion and vein-clearing on the young leaves.
- Cut and destroy the affected plants.
-Spray the ants with insecticides to get at the bugs.
- Plant resistant varieties.
Blackpod diseases
- Caused by fungus (Phytophthora palmivora and Phytophthora megakarya).
-Higher incidence in wet season than dry season because the spores of the fungus are easily dispersed by rain or water.
-Symptoms are brown spots which later turn black and spread over the pods rapidly.
- They destroy the entire pod and the seeds.
Preventive/control measure
- Remove all pod with symptoms and destroy them.
- Spray whole plant with copper fungicides e.g. perenox, once every 3 - 4 weeks.
- Weeding/Pruning to reduce relative humidity.