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Cocoa
Botanical Name – Theobroma cacao L.
Family -Malvaceae

Introduction

• Cocoa is an important commercial plantation crop of the world.
• Cocoa is a crop of humid tropics and so it was introduced as a mixed crop in India in areas where the environments suit the crop.
• It is cultivated in coconut and arecanut plantations large scale from 1970 onwards.
• It is grown as an under- storey intercrop with sufficient shade in southern states of India.
• In India, the current production is about 12,000 Metric Tonnes and Tamil Nadu produces about 400 Metric Tonnes.

Varieties

CCRP – 1 ,CCRP – 2 ,CCRP – 3, CCRP – 4, CCRP– 5, CCRP – 6, CCRP – 7,

CCRP – 8, CCRP – 9, CCRP – 10, CCRP – 11, CCRP – 12, CCRP – 13 ,CCRP – 14, CCRP – 15

Soil and Climate

• The natural habitat of the cocoa tree is in the lower storey of the evergreen rainforest, and climatic factors, particularly temperature and rainfall, are important in encouraging optimum growth. 
• Cocoa is a perennial crop, and it can withstand different seasonal variations with good health and yield potential.
• Cocoa is normally cultivated at altitudes upto 1200 m above MSL with an annual rainfall of 1000 mm to 2000 mm and a relative humidity of 80 % with maximum 350C and minimum temperature of 150C.
• Cocoa can be grown as intercrop in coconut and arecanut gardens.
• It is predominantly grown on red laterite soils.
• It thrives well on wide range of soil types with pH ranging from 4.5- 8.0 with optimum being 6.5- 7.0.

Season

June – July and September – October.

Propagation

• Cocoa can be propagated by seeds.
• Seeds are to be extracted from pods.
• Cocoa pods take 150-170 days from pollination to attain the harvest stage.
• The stage of maturity is visible from the change of pod colour from green to yellow (Forestero) and red to yellow (Criollo).

Collection of seeds from biclonal or polyclonal seed gardens involving superior self-incompatible parents is recommended to ensure genetic superiority of planting materials. 

In  coconut nursery, a poly clonal seed garden with 7 improved clones of KAU (CCRP1 to CCRP7)  and Vittal cocoa clone 1 and 4 hybrids namely VTLCH1 to VTLCH4.
Criteria for selection of mother plants for collection of seeds:

1. Forastero type (green- immature, yellow- ripe) having medium to large pods of not less than 350 g weight, smooth or shallow furrows on the surface without prominent constriction at the neck can be selected.
2. Husk thickness of pods should be less than 1 cm.
3. Pod value (number of pods to give 1 kg wet beans) should be less than 12.
4. Number of beans per pod has to be more than 35.
5. Bean dry weight to be more than 1 g.
6. The best seeds for sowing are those from the middle of the pod.

Vegetative propagation

• As the seedling progenies showed wider genetic variability, to maintain true to types, asexual or vegetative propagation is followed.
• Grafting and budding are being followed in multiplication of cocoa. 
• It also ensures multiplication of identified high yielding clones in large quantities.
• Though vegetative propagation of cocoa by budding, rooting of cutting and grafting are feasible, the widely accepted methods in India are budding and grafting.

Pot Mixture

The bags are filled with pot mixture containing.

• Red soil -2 parts
• Sand -1 part
• FYM- 1 Superphosphate – 5 kg/t of the above mixture
• This can be filled in 320 gauge polythene bag with 30 cm height and 20 cm width provided with two holes in the bottom.
• Nursery plants are ready for transplanting at 6 months of age when they attain a height of 60 cm.

Planting

• Cocoa is a shade loving plant.
• During its seedling period it requires about 50% shade and later the shade requirement is about 40%.
• The plant is grown as a mixed crop with other plants like spices and rubber mainly under rainfed conditions.
• Cocoa is planted as an intercrop in coconut and arecanut gardens.
• Pits of 50 cm x 50 cm x 50 cm are dug, allowed to weather for one month and refilled with topsoil and 15-20 kg of compost of FYM to ground level.
• Tear off the polybags carefully, place the soil ball with the seedlings in the planting hole with minimum disturbance and press the soil around firmly.
• Planting should coincide with the onset of monsoon, but in places where irrigation is resorted to, flexibility in the time of planting is possible.

Cocoa under Arecanut      Cocoa under Oil palm      Cocoa  under coconut

Irrigation in Cocoa

• Cocoa is usually grown in areas where water availability is adequate.
• Cocoa plants are sensitive to drought, irrigation in such cases becomes essential.
• During summer, as it exists in Southern India, the crop requires irrigation at weekly intervals.
• When it is grown as mixed crop with arecanut, the crop is to be irrigated once in a week during November-December, once in 6 days during January-March and once in 4-5 days during April-May with 175 litres of water. 

Manuring

Soil nutrient management 

• Soil nutrient management is critical to the general health of the tree, particularly where cocoa is grown on poor soils with low nutrient levels.
• The fertility of soils under cocoa plantations with complete canopy formation can be maintained or sustained for a fairly long time due to the ability of cocoa fallen leaves to recycle nutrients back into the soil and decomposition of leaf litter. 
• However, continuous harvesting will eventually result in loss of soil nutrients

Fertilizer schedule for cocoa

An annual application of the following schedule should be applied in two equal splits, the first dose in April- May and the second dose in September- October i.e. pre and post monsoon applications.

Method of application

• Fertilizer may be applied uniformly around the base of the tree up to a radius of 30 cm during the first year, forked and incorporated into the soil.
• For grown up plants the best method is to rake and mix the fertilizers with soil in shallow basins of around 75 cm.
• This radius may be increased gradually upto 150 cm after third year.
• Care should be taken not to spill the inorganic fertilizers on the trunk, branches or leaves of young trees in order to avoid burning

Fertigation

Drip (Fertigation)

• Fertilizers can be applied through drip irrigation system (fertigation).
• Weighed quantity of fertilizers as per schedule was dissolved in water and then injected to sub-main through venturi and then to lateral lines as per treatment.
• Drip irrigation is done once in 2 days.
• The fertilizers are applied through drip irrigation at weekly intervals. 100:40:140 kg of N, P and K are applied through drip and fertigation in different stages of crop growth as detailed below.

*Water soluble fertilizers      :  

• All 19(19% N: 19 % P: 19 % K), Mono – Ammonium Phosphate (MAP – 12:61:00 % NPK), Proprietary water Soluble form of N and K fertilizers containing 13% N and 45 % K (Multi ‘K’) and Urea (46% N)
• 100 % RDF as WSF through fertigation by drip irrigation recorded more pod weight (486.82 g), number of pods tree-1­ (56.87), Pulp + bean weight pod-1 (148.79 g), number of beans per pod (48.62), single bean fresh weight (3.10g), single bean dry weight (1.24 g) and dry weight of the beans per tree (3.429 g).

Pruning

• The basic aim of pruning cocoa trees is to encourage a tree structure that allows sunlight  to  filter  through  to  the  main  branches  and  trunk  (what  is  known  as  a jorquette)  to  stimulate  flowering  and  facilitate  harvesting.
• Pruning generally takes place twice a year.
• The first pruning is done after the main harvest (from April to July) and just before the rainy season, and the second pruning five months later, during the months of November and December.
• Young  plants  should develop  a  jorquette  at  a  height  of    about  1  meter.   
• It has been found that increasing light in-tensity decreases the jorquette-height.
• If a jorquette is considered too low, it can be cut off. The strongest of the re-growing chupon can be selected and all others removed.
• In  due  course,  this  chupon  will  produce  a  jorquette  at  a  higher  level. Vegetatively propagated plants generally form a jorquette at ground level.
• Fan     branches  should  be  limited  to  3  to  4  to  allow  more  light  to  enter  and  decrease the  humidity  within  the  canopy.
• Basal  chupons  should  be  removed  at  regular  intervals  and  all  lower  branches  that  form  or  bend  below  the  jorquette  should  be trimmed off.
• Furthermore  all  branches  within  60  cm  of  the  jorquette,  all  old  and  diseased branches  and  branches  growing  into  the  centre  of  the  tree  canopy  should  be  removed.
• This should be  done  at  regular  intervals  through  maintenance  pruning.
• All prunings should be left in the field to rot down, except the diseased ones.
• Diseased or unwanted branches with vascular die- back and water shoots are to be removed to maintain the health and vigour of the tees.
• It include removing all unnecessary chupons, dead branches, climbing plants, rodents- damaged and over ripe pods.
• Pruning the trees at 20 %  canopy removal will increase the number of flower cushions per tree and number of fruits per tree and it reduces the light transmission (12.72 %) and increases the  chlorophyll content (1.961 mg g-1)

After Cultivation

• Weeding is done as and when necessary.
• The unproductive shoots, dead, diseased twigs should be removed periodically.
• Banana is better raised as a primary shade plant in the early years of plantation.

Intercropping

• Plough the interspaces after the receipt of rain and raise either groundnut or black gram or bhendi till the trees reach bearing age.

Plant Protection

1. Mealy bugs (Planococcus lilacinus, Planococcus citri)

Symptoms-

• It colonizes on the tender parts of the plant such as growing tips of the shoots, the terminal buds, the flower cushions, the young cherelles and mature pods.
• Feeding of mealy bugs induces cherelle wilt.

Management-

• Spraying of Neem Oil 3% or fish oil rosin soap 25g/litre
• Spraying of any one of the following chemicals is recommended  : Dimethoate (2 ml/litre) , Profenophos (2 ml/litre), Chlorpyriphos (5 ml/litre), Buprofezin (2 ml/litre), Imidacloprid (0.6 ml/lit), Thiamethoxam (0.6g/litre)
• In the area where P. marginatus alone occurs, field release of Acerophagus papayae, the encyrtid parasitoid @ 100 per hamlet is recommended as the best management strategy.

2. Tea mosquitoe bugs (Helopeltis antonii)

Symptoms-

• Infested pods develop circular water soaked spots around the feeding punctures.
• Punctures subsequently turn pitch black in color.
• Deformation of pods occurs because of multiple feeding injuries.

Management

• Spraying of Neem Oil 3% is recommended.
• Spraying of any one of the following chemicals is recommended: Imidacloprid (0.6 ml/lit) , Thiamethoxam (0.6g/litre), Profenophos (2 ml/litre), Carbaryl (2g/lit)

3.Flatid Plant hoppers

Symptoms-

• Nymphs and adults suck the sap from flowers, tender shoots and pods.
• They excrete honey dew resulting in the development of sooty mould fungus on the leaves and pods.

Management: 

• Foliar application of a newer molecule Thiacloprid @ 2 ml/litre twice at 5 days interval is recommended for the management of these flatid plant hoppers.

4. Aphids (Toxoptera aurantii and Aphis gossypii)

Symptoms-

• They colonize on the underside of tender leaves, succulent stem, flower buds and small cherelles. 
• Heavy infestation may occur during hot summer and after rainy season which brings about premature shedding of flowers and curling of leaves.

Management-

•  Spraying of dimethoate @ 2 ml per litre

5.Hairy caterpillars (Lymantriya sp., Euproctis sp., Dasychira sp.,)

Symptoms-

• They cause serious leaf damage on seedlings and young trees.

Management-

• Foliar spray of acephate @ 2g/litre of water

6. Stem Girdler, Sthenias grisator

• Female beetle which girdles the branches and inserts whitish spindle shaped eggs singly into the tissue in a slanting manner.
• Due to mechanical injury caused by girdling and oviposition, the branches above the girdle wither and dry.

Management

1. Swab Coal tar + Kerosene @ 1:2 or carbaryl 50 WP 20 g / litre, after scraping the loose bark to prevent oviposition by adults.
2. Hook out the grub from the bore hole and apply monocrotophos 36 WSC 5 to 10 ml/ bore hole (or) one celphos tablet (3 g aluminum phosphide)/bore hole (or) apply carbofuran 3G 5 g/bore hole and plug with mud.
3. Injection of dichlorvas (DDVP) + monocrotophos solution into bore holes after removing the webs and subsequently sealing of the holes with clay gives satisfactory control of the pest.

Non- Insect pests

• Rats (Rattus rattus) and squirrels (Funambulus trisriatus and F. palmarum) are the major rodent pests of cocoa. 
• They cause serious damage to the pods.
• The rats usually gnaw the pods near the stalk portion whereas squirrels gnaw the pods in the center

Management

• The rats can be controlled by placing 10 g bromadiolone (0.005%) wax cakes or ripe banana stuffed with carbofuran on the branches of cocoa trees twice at an interval of 10-12 days.
• Squirrels are best controlled by trapping with wooden or wire mesh single catch ‘live’ trap with ripe coconut kernel as the bait.

Nutritional Deficiency

1.Nitrogen

Deficiency Symptoms :

• Leaves pale or yellowish in colour, older leaves finally show tip scorch.
• Younger leaves small, yellow or almost white in colour with little or no green associated with the veins
• Internodes are compressed and petioles show acute angle with stem

Corrective Measure :

1. Apply fertilizers in two equal split doses during April-May and September-October @ 100:40:140 g NPK/tree/year
2. In trees yielding more than 50 fruits per year, apply @ 200:80:280 g NPK/tree/year
3. Under irrigated conditions, apply the fertilizers in four splits during April-May, September-October, December and February-March
4. Apply 1/3 of recommended dose during the first year of planting, 2/3 during second year and full dose from the third year onwards

2.Phosphorous

Deficiency Symptoms :

• Growth is stunted
• Mature leaves paler towards the tip and margin, followed by tip and marginal scorch
• Young leaves reduced in size often showing interveinal paleness
• Young leaves show acute angle with stem and internodes are compressed

Corrective Measure :

1. Apply fertilizers in two equal split doses during April-May and September-October @ 100:40:140 g NPK/tree/year
2. In trees yielding more than 50 fruits per year, apply @ 200:80:280 g NPK/tree/year
3. Under irrigated conditions, apply the fertilizers in four splits during April-May, September-October, December and February-March

3.Potassium

Deficiency Symptoms :

• Pale yellow areas in interveinal region near leaf margin, which quickly becomes necrotic
• Marginal necrosis progresses more rapidly between veins with a yellow zone on inner surface

Corrective Measure :

• Apply fertilizers in two equal split doses during April-May and September-October @ 100:40:140 g NPK/tree/year
• In trees yielding more than 50 fruits per year, apply @ 200:80:280 g NPK/tree/year
• Under irrigated conditions, apply the fertilizers in four splits during April-May, September-October, December and February-March
• Apply 1/3 of recommended dose during the first year of planting, 2/3 during second year and full dose from the third year onwards

4.Calcium

Deficiency Symptoms :

• Necrotic areas in interveinal region near leaf margin, which quickly fuses into continuous marginal necrosis of older leaves

Corrective Measure :

• Apply Dolomite @ 100 g/plant/year from the third year onwards

5.Magnesium

Deficiency Symptoms :

• Necrotic areas in interveinal region near leaf margin.
• Prominent bright yellow zone in advanced necrotic areas and islands of necrotic tissue also appear in later stages
• Unaffected areas of the leaf pale green than usual and develops oak leaf like pattern.

Corrective Measure :

1. Apply Dolomite @ 100 g/plant/year from the third year onwards

Disease

1. Seedling blight (Phytophthora palmivora)

• On leaves, small water soaked lesions appear which later coalesce in the blighting of leaves.
• On stem, water soaked lesions develop initially and later turn to black colour.
• Stem infection develop any point on the stem causing the death of seedlings.

 Management:

• Remove and destroy the affected seedlings.
• Spray with 1 percent Bordeaux mixture or 0.2% copper oxychloride just before the onset of monsoon and thereafter at frequent intervals.

2. Black Pod rot (Phytophthora palmivora)

• Infection appears as chocolate brown spot, which spreads rapidly and soon occupies the entire surface of the pod.
• Whitish growth of fungus consisting of fungal sporangia is produced over the affected pod surface.
•  Affected pods turn brown to black.
• The internal tissues as well as the beans become discolored as a result of infection.
• The beans in the infected pods approaching ripeness may escape infection because they are separated from the husk on ripening

Management:

• Remove the infected pods. 
• Spray 1 per cent Bordeaux mixture with on set of monsoon and also frequent intervals.
• Provide frequent drainage and regulate shade to increases aeration. 
• Pseudomonas fluorescens (Pf1) liquid formulations @ 0.5% as soil and foliar spray (3 times per year- June, October & February) was found to be effective in reducing the Cocoa Pod rot and Stem canker.

3. Stem Canker (Phytophthora palmivora)

• The cankers appear either on the main trunk, jorquettes or fan branches.
• Appearance of a greyish brown water soaked lesion on the outer bark.
• A reddish brown liquid oozes out from these lesions, which later dries up to form rusty deposits.
• The tissues beneath the outer lesion show reddish brown discoloration due to rotting.

Management:

• Controlled in the initial stages by the excision of diseased bark followed by wound dressing with Bordeaux mixture or copper oxychloride paste .
• Wilted branches should be cut and removed

4. Vascular Streak Dieback (VSD)

• It is reported from some parts of Kerala.
• Yellowing of one or two leaves on the second or third flush behind the growing tip.
• Diseased leaves fall within a few days of turning yellow and the other leaves on the shoot show similar symptoms.
• When the infected shoot is split lengthwise there is always a characteristic brown streaking.

Management-

• Disposing diseased branches and regular pruning of chupons on the trunk.
• Cocoa nurseries should not be located near the diseased area.
• Avoid getting seedlings from diseased tracts.
• Kerala Agriculture University has developed some VSD resistant and high yielding varieties CCRP-1 to CCRP-7.

5.Cherelle wilt 

• Shriveling and mummifying of some young fruits are a familiar sight in all cocoa gardens.
• Fruits lose their lustre and in four to seven days they shrivel.
• Fruits may wilt but do not abscise.
• Many other factors like insects, diseases, nutrient competition and over production may also be associated with this problem.

Harvest

• Bearing starts from 3rd year but economic yield starts from 6th year onwards.
• The season of harvest is April – May and November – December.

Yield

50-70 pods/tree/year