School Science Lessons
Please send comments to: J.Elfick@uq.edu.au
Table of contents
5.0 Cocoa flower
4.0 Cocoa leaf
8.0 Cocoa pod
9.0 Cocoa seeds
6.0 Cocoa seeds in the pod
1.2 Cocoa shade trees, (Primary)
3.0 Cocoa tree
1.3 Cocoa planting, (Primary)
1.4 Cocoa plants, Care of coca plants,
11.0 Cocoa seed, Choose and plant seeds
10.0 Cocoa seed bed
22.0 Drying, bagging and shipping beans
21.0 Fermenting cocoa beans
19.0 Fertilizers for cocoa
20.0 Harvest cocoa pods
1.5 Harvesting and fermenting cocoa,
1.1 History and Importance of cocoa,
17.0 Mulch and weed cocoa
23.0 Pests and diseases of cocoa
1.6 Pests and diseases of cocoa, (Primary)
7.0 Pollination and fertilization
14.0 Prepare land for cocoa
18.0 Prune the cocoa tree
25.0 Returns, costs and profits
28.3.0 "Scientists put cocoa under the microscope"
15.0 Shade trees for cocoa
13.0 Soils for cocoa
16.0 Transplant cocoa
12.0 Varieties of cocoa
2.0 Where cocoa will grow, (Primary)
22.1 Chocolate and cocoa manufacture
28.0 Chocolate recipes
27.0 Chocolate, Commercial chocolate
Pests and diseases
23.1.3 Amblypelta cocophaga bug
23.2.2 Bark Canker, Ceratocystis fimbriata
23.2.1 Black pod disease, Phytophthora palmivora
23.1.1 Cocoa capsid bugs, Helopeltis,
23.1.2 Cocoa weevil borer, Pantorhytes
23.2.3 Dieback, vascular streak dieback virus
23.2.7 Frosty pod rot of cacao
23.1.6 Giant African snail, Achatina fulica
23.1.10 Insect pest control methods
23.1.9 Insect pests of Cocoa in Papua New Guinea
23.1.8 Insect pests of Cocoa in Solomon Islands
23.1.5 Longicorn beetles, Glenea lefebueri
23.2.4 Pink disease, Botryobasidium salmonicolor
23.2.5 Thread blight, Corticium incisum
23.2.6 Witches' broom disease of cacao
1.0 Introduction to the cocoa
| See diagram 55.4: Cocoa pod
| See diagram 55.1.0: Weeding the cocoa project
1. Cacao is a broad-leaved evergreen that grows between 20o
north and south of the equator, and reaches about l7 m in height.
Its fruits are fibrous pods from 15-25 cm long and 7.5 -10 cm in diameter
and containing 20 to 40 seeds, "beans," each about 2.5 cm
long, embedded in a sweet tart pulp.
Cocoa is a cash crop.
Cocoa growing can be profitable if the right kind of cocoa is grown, it
is properly raised in a seed bed, it is planted properly under
enough shade and in the right kind of soil, it is cared for properly
as it grows including proper pruning, weeding, mulching, fertilizing
and protection from diseases and pests, and it is harvested and processed
Cocoa is produced in tropical countries, but is processed and consumed
in temperate countries.
2. Cocoa grow best under the canopy of tropical rainforests, seldom reaching
more than 7.5 m height.
They need to be shaded from direct sun and wind, particularly in the early
The cocoa tree has broad, dark leaves about 25 cm long, and pale, coloured
flowers from which bean pods grow.
Cocoa is an under-storey species from on the equatorial slopes of the
Andes Mountains in South America, but is now cultivated widely.
Two thirds of the world's production comes from West Africa and one third
from Brazil and Dominican Republic.
Cocoa has about 20 subspecies and cultivars are named according to the
place where they were found or developed.
3. Two methods are generally used to establish cocoa tree plantations.
3.1 Young trees are interspersed with new permanent or temporary shade
trees such as coconut, plantains and bananas, following the
clear-felling of the forest.
In large Asian plantations, cocoa trees and coconut trees are planted
together and both crops are harvested commercially.
3.2 Alternatively, forest trees are thinned out and the cocoa trees are
planted between established trees.
There are three broad types of cocoa: Forastero and Criollo, as well as
Trinitario, a hybrid of the two.
Within these types there are several varieties:
1. Criollo types have elongated, ridged, pointed fruits and white cotyledons.
They produce relatively mild beans with some of the finest and most delicate
flavours, but they are also disease prone, low yielding
trees, and so provide only a small proportion of the world crop.
Criollo: With its mild or weak chocolate flavour, Criollo is grown in
Indonesia, Central and South America.
Criollo trees are not as hardy and produce softer red pods, containing
20-30 white, ivory or very pale purple beans.
2. Forastero variety produce the greater part of all cocoa grown, Forastero
is hardy and vigorous, producing beans with the strongest
The Forastero variety most widely grown in West Africa and Brazil is Amelondaro.
It has a smooth yellow pod and pale purple beans.
Forastero types have with short, roundish, almost smooth fruits and purple
cotyledons (2n = 20).
They are high yielding and robust so provide most of the world's cacao
crop in the form of full-flavoured "bulk" beans.
3. Trinitario are hybrids of a Criollo and Forastero, and have intermediate
Trinitario plants are not found in the wild as they are cultivated hybrids
of the other two types.
Trinitario cocoa trees are grown mainly in the Caribbean, but also in
Cameroon and Papua New Guinea.
The mostly hard pods contain 30 or more beans of variable colour, though
white beans are rare.
Cacao is classified in the plant family Sterculiaceae and has the botanical
name "Theobroma cacao L".
Some botanical names have "L" after them to show that they were named
by the famous Swedish botanist Linnaeus (1707 - 1778).
He believed that the ancient Aztecs of South America thought that the
cocoa drink was a "drink of the gods", in Latin "theo broma".
Mexicans named the pounded seeds "chocolate".
Cocoa is now grown in many hot wetlands including the Pacific islands,
but it needs a rich deep soil so this tree cannot be grown on
the coral atolls.
3. The seeds of cocoa called cocoa "beans" are used to make chocolate.
Fermented seeds are roasted, cracked and ground to give a powdery mass.
Fat is taken out to make cocoa.
Cocoa has many uses including folk medicine.
The seed contains energy, protein, fat, Ca, Mg, P, Fe, carotene, thiamine,
riboflavin, niacin, and ascorbic acid.
Chocolate is particularly high in phenylethylamine and contains more than
300 volatile compounds and theobromine, a stimulant
related to caffeine.
(Theobromine does not contain bromine!).
It contains some caffeine, in milligrams:
Cup: expresso coffee 310 mg, boiled coffee 100 mg, instant coffee 65
mg, tea 10 to 50 mg, cocoa 13 mg
Can: Coca Cola, 20 mg, Can (6 oz.) Pepsi Cola: 10 mg.
4. The cacao "bean" consists mainly of the embryo's cotyledons and contain
two distinct groups of cells.
About 80% of the cells are storage depots of protein and of fat, cocoa
butter, that will feed the seedling as it germinates and develops.
The other 20% of cells are defensive cells to deter forest animals and
microbes from consuming on the seed.
These cells are seen in the cotyledons as purplish dots that contain astringent
phenolic compounds, anthocyanin pigments, and two
bitter alkaloids, theobromine and caffeine. The beans contain about 65%
3.0 Cocoa tree
See diagram 55.3: Parts of a cocoa tree
1. The tree is 4 to 8 m tall.
At 1 to 1.5 m the terminal bud breaks into 3 to 5 meristems to give upright
It has spreading branches, stipules 5 to 14 mm long, large green leaves
The ovary has 5 carpels. The fruit is a drupe but is called a pod.
The pod does not open, indehiscent, and stays on the tree.
Pods vary in size and shape, being 10 to 32 cm long, spherical to cylindrical,
pointed or blunt, smooth or warty, with or without 5 or
10 furrows, colour white or green or red, ripening to green or yellow
or red or purple.
The pod has 20 to 60 seeds arranged in 5 rows, variable in size, 2 to
4 cm long, ovoid or elliptic shape and 625 to 1 125 seeds per kg.
The roots are mostly surface feeding with tap root penetrating to 2 m
in friable soil
2. Go to where cocoa trees are growing.
How high is the tree?
Has it got a big canopy of leaves?
Does the canopy of leaves have a mostly level base? Is the tree growing
in a shady place?
How much of the tree is in sunlight? How thick is the tree trunk at the
Are there any water suckers called chupons growing from the trunk?
The trunk branches into several of smaller branches called the fan.
Go up close to the trunk and look for flowers.
The clusters of flowers grow out from small cushions on the side of the
trunk. Pick a large leaf.
What colour is it?
How long is it?
What is its shape and size?
After the flowers have formed, a small pod grows.
The pod grows larger until it is ripe.
Measure the length and width of a big pod.
Open one pod to see the seeds, called "beans", inside.
Estimate how much shade and full sun on the tree.
Measure the thickness of the trunk and the height of the fan above the
Look very closely at a flower and describe it.
Look at the places where the flowers grow out from the trunk at a small
swelling called the cushion.
Pick a leaf.
Pick a ripe pod and open it to see inside.
4.0 Cocoa leaf
1. Observe the length and breadth of a leaf.
Describe the shape of the leaf and the colour of the leaf.
Young leaves may have a reddish or yellowish colour.
The colour of leaves at the top of the tree is often different from colour
of leaves growing low down on a tree.
Note the difference between the colour of young and old leaves.
Most cocoa leaves ends in a sharp point called the "drip tip".
Measure the length and thickness of the leaf stalk, petiole.
Note whether the leaves are held out sideways or hang down.
5.0 Cocoa flower
See diagram 55.5: Cocoa flowers and young pods
The flowers are formed in groups that grow out from small cushions on
the main trunk and older branches that have no leaves.
At first the flowers are small buds.
Later they open.
The opened flower has five long pink sepals joined at their bases, but
the upper parts are long and pointed.
The five yellowish petals have a most unusual shape.
The base of the petal is very narrow.
Then it widens to form a hollow sac-like pouch.
At the top of this part is a long narrow extension bent backwards and
ends in a broad flattened tip.
The male parts of the flower are in two groups.
An outer row of five staminodes are sterile male parts that make no pollen.
These long pointed staminodes point straight up out of the middle of the
An inner row of five stamens has an unusual shape.
The stalk or filament that carries the anthers is bent over
so that the male anthers are carried inside the hollow sac part of the
The female parts of the flower consist of an ovary with five divisions.
Each division or carpel has a long style or stalk, but the five styles
are all joined at their base.
At the top of the style five separate lobes, stigmas, receive the pollen.
1. Find the cushions from which the flowers grow.
2. Pick up a few flowers that fall off and do not develop.
3. Take off the 5 sepals.
4. Remove one petal.
5. Remove the five staminodes.
6. Look for the stamens.
They are very small.
7. Look carefully on the ground under a tree and count the number of
6.0 Cocoa seeds in the pod
See diagram 55.6: Seeds in the pod Cocoa trees
begin to bear fruit when they are three to four years old.
They produce pink and white flowers throughout the year, growing in abundance
after before the rain starts.
However the pods grow straight out of the trunk and the main branches,
which is most unusual.
Only a small proportion of the flowers develop into fruit over a period
of about five months.
The trees are carefully pruned so that pods can be more easily harvested.
Each tree yields 20-30 pods per year.
It takes the whole year's crop from one tree to make 450 g of chocolate.
Cocoa trees only start to bear fruit when they are 4 or 5 years old.
Open a ripe fruit is by hitting it on the outside with a piece of stiff
Once a young fruit is 3 months old, it will usually stay on the tree
and grow properly.
It usually takes about 6 months for a fruit or pod to be ripe.
The pod is ripe when the beans are loose and the pod will rattle when
When the fruit is opened, these are the parts that can be seen:
1. On the outside is the thick coat or husk.
This coat may have deep grooves in it or shallow grooves.
It may also have a lumpy surface with a warty appearance.
It may be soft or hard and woody.
2. The large seeds or "beans" are in the centre of the pod.
Each pod may have 20 to 60 seeds in it.
3. All around the seeds and between the seeds and the outside husk is
a mass of white or pink soft pulp.
4. The pod has a strong stalk.
5. The pods may be up to one foot or 30 cm long and may be four inches
or 10 cm wide.
6. The shape of the pods depends on the variety grown.
Most cocoa trees are of the Forastero or Amelonado types, and these have
short pods with a blunt end.
The surface of the husk is not deeply grooved and is smooth, not warty.
These pods are usually a yellow colour.
Cocoa trees of the Criollo type are long and deeply grooved and form a
point at the end.
They are usually reddish in colour.
Other shapes and colours of pods may be found in trees that are hybrids
or crosses between different types of cocoa trees.
The water shoots are called chupons.
The flower has 5 sepals and 5 yellow petals.
The long sterile male parts that make no pollen are called staminodes.
The female ovary has 5 parts.
7.0 Pollination and fertilization
1. Flowers arise from cushions in the wood of the main stem and fan branches
that is at least 2 to 3 years old.
Only 1 to 5% of flowers are successfully pollinated and form pods.
Pollinating insects are mainly tiny midges, e.g. Forcipomyia, and other
small insects that require cool, dark, moist habitats and breed
in rotting vegetation.
When the male pollen is taken to the female stigmas by midges, the flower
When the pollen grains grow down into the ovary, it will be fertilized.
Only about one flower in 500 becomes a fruit.
Many fertilized flowers drop off the tree.
Even when a flower turns into a fruit, young fruits often shrivel up and
drop off the tree when only 7 or 8 weeks old.
A bad time or lack of plant food may cause this.
Although only a few flowers are pollinated, the tree sets too many fruit
to carry to maturity.
Cocoa has a fruit thinning mechanism where the young fruit, called cherelles,
stop growing, turn black and shrivel but do not fall off the
This is called cherelle wilt but it is not a disease, it is natural.
The remaining pods take 5-6 months to ripen after pollination.
Ripe pods also do not open by themselves or fall off the tree.
8.0 Cocoa pod
See diagram 55.6: Cocoa pod
1. The cocoa tree bears two harvests of cocoa pods per year.
Around 20 cm in length and 500 g in weight, the pods ripen to a rich,
Within each pod there are 20-40 purple, 2 cm long cocoa beans covered
in a sweet white pulp.
2. There are many ways of telling if the pod is ripe.
The beans will be loose inside a ripe pod and will rattle if you shake
If the pod is ripe, the gum of the seeds will be slippery and it will
If the gum around the seeds is dry and if the seeds do not fall apart,
the pod is not ripe.
3. Describe the outside of the pod.
Is it grooved or smooth?
Is the surface lumpy or warty?
What colour is it?
What type of cocoa is it likely to be?
4. Open the pod by hitting it with a strong stick.
Use a sharp knife to cut cleanly across the wall of the pod and the soft
5. Scoop out all the seeds from the pod.
Count the number of seeds.
6. All the seeds are joined to a long white part running down the centre
of the pod.
9.0 Cocoa seeds
See diagram 55.9: Cocoa seed and its parts
Study some seeds and note the following:
1. Where the seed was broken off from the central white part, it leaves
a small mark on the outside of the seed.
This is very important because when a seed is planted this mark must be
placed downwards in the seed bed or seed tin.
2. When the seed or "bean" is cut open the following parts can be seen:
2.1 The seed has a tough seed coat or testa.
2.2 The outer part of the seed coat is the soft pulp surrounding the
2.3 The small plant or embryo (or "germ") is at one end of the seed.
2.4 The main part of the seed consists of the two seed leaves or "cotyledons"
where the starchy food is stored.
2.5 A small mark on the outside of the seed coat shows it was once joined
to the central white part of the pod.
3. Use a knife to cut the seed on the flat, not across them, then look
for the embryo, small plant.
Note the seed leaves, cotyledons, where the food is stored.
Note the colour and thickness of the seed coat or testa.
4. The seeds are self incompatible and are cross pollinated by midges.
The pods contain up to 50 seeds surrounded by juicy sweet pulp.
In nature the seeds are distributed by animals, usually monkeys.
The seeds are rich in fat, called chocolate butter and contain alkaloids,
e.g. theobromine giving them a bitter taste.
5. Germination occurs best in dim light.
The seeds have limited viability and no dormancy.
A tree bears pods at 4 or 5 years.
A pod has 20 to 60 seeds (beans).
The average pod is 30 cm long.
Amelonado or Forastero varieties have short pods with no pointed ends.
Criollo cocoas have yellow or red pods, with rough surface and deep grooves.
Amelonado cocoa pod is smoother and rounder and the seeds have dark purple
Trinitario pods have many shapes.
A pod takes 6 months to be fully grown and ripe.
Plant a cocoa seed with the small mark downwards.
The small plant inside a bean is the embryo.
The outside coat of a seed is the testa.
A Criollo pod is red or yellow.
An Amelonado pod is yellow.
10.0 Cocoa seed bed
See diagram 55.10: Seed bed for cocoa
1. The seedlings must have shade so build a small roofed shelter over
the place where you will plant the seeds.
2. The seedlings need good soil.
Get some good dark soil and break up the lumps until it is fine and loose.
Then mix a little manure with it. Spread this soil over the soil in the
seed bed area, and place the seeds into it.
Also, you can put the soil into jam tins or pieces of bamboo or plastic
bags with holes in them near the bottom.
3. Keep the seedlings wet.
They must be watered every day.
4. Do not allow weeds to grow near the seedlings.
If insects come to eat the leaves of the seedlings, they must be killed.
11.0 Cocoa seed, Choose and plant
| See diagram: 55.10: Nursery
| See diagram 55.11: Right and wrong ways of harvesting
1. Prepare the land to be ready for planting the seedlings.
If about 60 cocoa seeds or beans are planted at least 50 will germinate
Discard the 10 weakest seedlings leaving 40 cocoa seedlings.
Plant the cocoa seedlings 3 m apart each way.
So the piece of land must be 15 metres wide and 18 metres long.
Put stakes in the soil at each planting place.
2. Propagation may be by cuttings, buddings or graftings, but seeding
Seeds germinate at maturity, and are viable only a short time.
They may be stored 10 to 13 weeks if moisture content is kept at 50%.
Soon after picking, pulp is removed from seeds that are then planted in
shaded nursery beds or baskets.
Collect seed from ripe pods and plant immediately. At least 90% should
germinate within 2 weeks.
Hybrid seeds are available but the plants can be highly variable in growth
Planting of seed direct to the field is not practised due to lack of irrigation
and problems with weed and pest management.
3. Choose a pod of the right variety from a high bearing tree.
Chose only an Amelonado pod of large size from a high bearing tree.
4. The pod must be ripe and healthy.
A ripe pod will have loose seeds inside when shook.
Use a knife to cut off the pod leaving some stalk on the tree.
Never pull the pod from the tree because you may pull off the cushion
and then it cannot make any more flowers.
5. Select only the best seeds for planting.
Open the ripe pod by hitting it with a stick.
Do not use a knife because it might cut the seeds.
Discard the small seeds at each end of the pod.
Use only the big seeds in the middle of the pod used for planting.
6. Sow the large seeds soon after they are taken from the pod.
Do not keep the pod for more than a week because the embryo will die.
7. Hold the seeds by the flat sides and with the small scar pointing
Push the seed down into the moist soil until it is just covered.
Do not push the seed in too deeply or it will not grow well.
8. If the seeds are planted in the soil and not in tins, plant them in
rows 25 cm apart.
Leave a space of 25 cm between the seeds in a row.
9. Water the seeds after planting.
12.0 Varieties of Cocoa
See diagram 55.12: Three groups of cocoa varieties:
Criollo, Forastero Trinitario
1. Plant only the best varieties of cocoa.
Most of the common cocoa varieties cross or breed with one another so
there are many cocoa varieties.
The two main groups of cocoa varieties are the Criollo and Forastero cocoas.
2. The Criollo cocoas have yellow or red ripe pods and the pods have
deep grooves on the outside and the surface of the pods is
rough or warty.
The ends of the pods are pointed.
The seeds or beans are large and rounded with white or pale violet seed
These cocoas have a much better taste than other cocoas, but are not common.
3. Forastero cocoas are the most common.
The pods are not as deeply grooved as the Criollo cocoas and may even
The ripe pods are green or yellow, and the wall of the pod is very thick
The pods are also shorter and more rounded.
The two groups of Forastero cocoas are the Amelonado cocoas with yellow
pods with flat seeds that have deep purple seed leaves
inside and the Trinitario cocoas, probably crosses between Criollo and
Forastero cocoas because the pods look like Criollo and
4. The best varieties to grow are the Amelonado cocoas because they are
hardy, more vigorous, and yield well.
13.0 Soils for Cocoa
See diagram 55.13: A good soil and 3 bad soils
1. Cocoa needs rich, organic, well drained, moist, deep soils.
Shallow soils are not suitable.
It will not grow well on waterlogged soils, shallow stony soils, or soils
with a hard stony layer near the surface.
Also, cocoa will not grow on coral soils, so it cannot be grown on atoll
If a cocoa tree is to grow well, it needs more than anything else a soil
of good structure, permeable and deep.
The cocoa tree has tap-roots.
The tap-root descends straight into the soil.
The branch roots go down very deep.
But many small branch roots also grow near the surface.
If the soil is of good structure and contains much humus, the roots penetrate
You can improve the soil structure by spreading manure and working it
into the soil.
If the soil is deep, the roots can go down to a good depth.
Never plant cocoa trees in soil with a lot of stones, or in soil where
there is some hard layer.
2. Cocoa is grown on a wide range of soil types but soils with moderate
to high fertility are favoured, because� fertilizer inputs under
traditional production systems are low.
The best soils for cocoa are soft loose deep soils with good structure,
e.g. clay loam.
The main needs are a free draining soil with good moisture holding capacity
and pH range from 4.5 to 7.0 preferably close to 6.5. 3.
The soil should be at least 1.5 metres deep.
Shallow soils do not give cocoa enough root room.
If the soil has been dug often to a certain level, the soil under where
they have been digging will be hard and form a soil pan.
This will restrict the roots of cocoa and cause a swampy soil.
If the water table is close to the surface, the roots have no room to
grow in this soil, the trees have no "root room".
4. Dig a hole in a place where cocoa is growing to see if it is loose
14.0 Prepare cocoa land
See diagram 55.13: Plan of a small plantation
for 40 cocoa trees | See 6.9.14:
1. Clearing the site
If the method is to cut down all the trees and to burn everything all
the organic matter in the weeds, leaves and branches are destroyed
leaving the soil bare to the sun or rain.
The soil becomes less fertile and the cocoa trees are not protected from
the sun when it is too strong.
2. Banana and taro can give shade for the young cocoa trees.
If they are planted long enough before the cocoa trees, they give good
protection, but if they are planted at the same time as the
cocoa trees, they do not protect the young cocoa trees well enough and
they take nourishment out of the soil.
To give shade it is better to keep a few of the forest trees, e.g. Terminalia,
Ficus, Albizzia, Alstonia, Pycnanthus.
3. First cut all the grass, tall weeds, creepers, bushes and small trees.
Make heaps of what you have cut down and arrange the heaps in rows.
Do not burn all the vegetation you cut.
Leave it on the ground to keep the soil moist and protect it erosion.
Leave the heaps to rot to make humus.
If you must burn the vegetation you have cut, you must sow a cover crop.
Next, cut down all the trees which might give some disease to the cocoa
trees and cut down trees that give too much shade.
When the cocoa trees have grown taller, they need less shade.
You should gradually give them less and less shade.
You should prune the big trees and cut off those branches that cast too
Later, cut down all the big trees.
When the cocoa trees have grown, it is better to get rid of the unwanted
shade trees, by using tree-killing chemical products.
This way causes less damage than cutting them down.
4. Choose a suitable piece of land that is good enough for cocoa with
area big enough for the school project.
4. Provide some shade for the young cocoa seedlings with coconuts about
9 m apart or shade trees, e.g. Leucaena.
They are fast growing legumes that put nitrogen into the soil and giving
15.0 Shade trees for cocoa
| See diagram 55.15: Planting cocoa and Ikofala
ants nests made out of leaves
| 4.26 Leucaena leucocephala
1. Shade may be remnant forest, interplanting with species that provide
a commercial return, e.g. bananas or coconuts or shade trees
selected on basis of amount of nitrogen fixed if a legume, fuel wood
produced, suppresses weeds, and grows well with cocoa.
Shade trees include species of Albizia, Erythrina, Gliricida,
Inga, Leucaena, Musanga, and Peltophorum.
Ask an officer of the Department of Agriculture to recommend supply of
2. Dig trenches one metre long in between the cocoa, or plant Leucaena
seeds in strips or one metre long between cocoa planting
Mark out strips of soil one metre long between the stakes where cocoa
seedlings will be planted.
3. Into each of these strips spread about 20 Leucaena seeds and
cover them up with 3 cm of soil.
Weed the strip each week.
When about 1.3 m high, pull out the smaller shade plants leaving the three
biggest at each strip.
When the shade trees are 2 m high, the cocoa seedlings can be planted.
4. Look in small trees for Ikofala ants nests made houses out of leaves.
These ants help to keep pests away from cocoa.
Put wooden stakes at each of the 40 planting positions.
5. Cocoa grows well if it has part shade at first but as the tree grows,
some shade trees are removed.
Seedling cacao does best with only 25% full sunlight, saplings with closer
Cut the stem of Leucaena shade trees just below the soil surface.
Cocoa can be grown without any shade, but the trees do not grow well and
much fertilizer must be used.
Shade removal is possible after 3 to 4 years but in many situations windbreaks
will be beneficial or necessary.
16.0 Transplant cocoa
| See diagram 55.16: Dig a hole for cocoa a month
| See diagram 55.16a: Planting hole
1. If the cocoa trees are not planted in rows, there is not the same
distance between them.
When the trees are too far apart, they do not use all the soil and when
they are too close, they grow badly.
So always plant in rows.
Sometimes growers sow cocoa seeds straight away in the plantation.
This is a bad thing to do.
It is better to put into the plantation either young cocoa seedlings from
your own nursery beds, or cocoa seedlings bought from a
A few hours before lifting the seedlings from the nursery beds, water
Then take the seedlings out of the nursery beds with a spade or a hoe.
Be very careful not to break the roots.
Next sort out the cocoa seedlings.
Throw away diseased plants and plants that have a twisted tap-root.
You can dip the roots of the seedlings in liquid mud, so that the cocoa
plants take root again easily.
2. Transplant 3 to 6 months after planting when about 0.6 m tall into
shaded fields at 2.4 m × 2.4 m or 3.6 m × 3.6 m.
Use stakes to mark the positions where the cocoa will be planted.
Planting density may range from 800 to 3 000 trees / ha with about 1 200
trees / ha common in under permanent shade.
If planting 2.5 to 3 metres between rows and 2.5 to 3 metres between trees,
you can plant about 1 000 to 1 600 seedlings per hectare.
3. Before planting cocoa trees, dig the holes to stir the earth and loosen
it during one to two months before planting the cocoa trees.
When you are digging the hole, do not mix together the top soil from
above and the subsoil from below, but make two separate heaps,
as in the diagrams above.
Dig the holes 30 cm wide and 45 cm deep.
4. A few days before planting, fill in the holes you have dug.
At the bottom of the hole, put the topsoil you have dug out from the top,
and on top put the subsoil you have dug out from below.
You may mix the soil with manure.
5. When the seedlings are about six months old, take them out of the
nursery seed beds or gradually take away the shade cover so
that the seedlings get used to the sun.
Discard weak seedlings.
They should not be used for planting.
6. When you are ready to plant, make a small hole.
In this small hole place your young cocoa seedling.
If you have sown your seeds in baskets or bags, make a hole big enough
to hold the root ball with the cocoa seedling.
Be very careful not to twist the tap-root.
Do not cover the crown with earth. Pack the soil down well around the
For the first few days, protect the cocoa seedling from the sun.
If there are palm trees in your village, use a palm frond.
7. Transplant the cocoa seedlings at the beginning of the rainy season.
Choose a day when the soil is moist and when the sky is cloudy.
Plant the young cocoa trees when they are about 6 months old.
8. Use a spade to dig up seedlings from the seed beds and keep a ball
of earth around the roots.
If the seedlings were raised in tins or pots or bags, remove carefully
to keep the earth around the roots.
Turn the seedling in a tin upside down and tap the edge of the sharply
on something hard.
9. Plant the seedlings into a hole in the topsoil then put soil around
the seedling level with the soil surface.
Then water the seedling.
17.0 Mulch and weed cocoa
See diagram 55.17: Mulch
1. A mulch is any light loose covering laid on the surface of the soil.
The commonest mulch is made of dead weeds, but any kind of plant rubbish
can be used.
A mulch helps plants on the following ways:
1.1 helps to keep the surface of the soil moist and cool.
In cold weather it keeps the soil warm,
1.2 protects the soil and stops heavy rain washing away the topsoil,
1.3 helps to keep sun off the weeds and stops their growing,
1.4 keeps the surface of the topsoil soft and moist,
1.5 contains some nutrients, plant foods, which can be washed down into
However, in a dry climate with only occasional light rain, too much mulch
may absorb all the rainfall, so that no moisture reaches the
2. To make a mulch, clear a one metre circle around each cocoa seedling
then cover the ground with mulch 10 cm thick.
Leave a small clear space of the bare soil around the seedlings so that
the mulch does not touch the seedling.
The clear space helps to stop the attack of pests.
As the tree grows bigger, widen the area covered by mulch until all the
soil is covered.
Do not use pieces of wood or sticks as mulch because they take too long
to rot down.
Weed 3 to 4 times in the year during the establishment phase, before the
canopy closes by manual slashing along the tree rows or
around young plants.
Also, use herbicides, e.g. "Gramoxone" and "Roundup".
For the efficient application of herbicides, plant the cocoa trees in
When cocoa is mature and a complete canopy is formed, heavy shading and
leaf mulch inhibit weed growth so only a few woody
weeds must be removed.
However, breaks in the canopy or equipment access paths allow weeds to
18.0 Pruning the cocoa tree
See diagram 55.18: Pruning
1. As the cocoa seedling grows it has to be pruned so it will grow into
the right shape for cocoa and to limit tree height for harvesting.
The young tree forms a straight main stem about 1 to 1.5 metres high.
It then branches into 3 to 5 main fan branches, called the first jorquette.
The tree then makes two kinds of branches:
1.1. Fan branches with leaves growing flat along both sides of the stem.
1.2. Sucker branches called chupons with leaves growing all the way around
When the first fan branches have formed then chupon branches will grow.
If chupons are left on the tree, it will grow into a bad shape with two
or three fans, one above the other.
So cut off all the chupons as soon as they are seen to prevent subsequent
jorquettes and restrict further vertical growth.
Also, prune fan branches to maintain evenness in the structure, dead or
diseased branches or any branches that hang down low.
Otherwise, never prune fan branches.
Remove floral buds until trees are 5 years old.
4. Use a sharp knife, secateurs or pruning saw and cut close to the main
stem to prevent the chupons growing again.
If the pruning cut is large, paint it over with tar or creosote or another
chemical to kill fungi.
Apparently pruning itself does not promote high yields.
19.0 Fertilizing cocoa
See diagram 55.19: Drip circle for cocoa
About 200 kg N, 25 kg P, 300 kg K, and 140 kg Ca are needed per ha to
grow the trees before pod production.
For each 1 000 kg of dry beans harvested, about 20 kg N, 4 kg P, and 10
kg K are removed if the pod husks are also removed from
the field, the K removed increases to about 50 kg.
You can use soil and leaf analyses to find the nutritional needs of cocoa.
Leaf analyses are not accurate due to the difficulty in sampling leaves
of the same age and the influence of shading on the nutrient
composition of leaves.
Some experts can use visual symptoms of mineral deficiencies to recommend
use of fertilizers.
Ask an agriculture officer which fertilizers should be used.
Some common fertilizers:
It has much nitrogen in it (46%) but it makes the soil a bit sour (acid)
and some nitrogen may be lost into the air
Sulfate of ammonia
It has nitrogen (21%) and sulfur (24%) in it.
Do not use this on an acid soil because it makes the soil more acid.
Calcium ammonium nitrate has 20% of nitrogen in it, but it also has calcium.
Use it on acid soils.
Superphosphate has phosphorus nutrient in it, but it also has calcium
Triple superphosphate has much more phosphorus in it, but it is much
more expensive to buy.
Muriate of potash contains 60% potassium oxide but is expensive.
Sulfate of potash contains potassium and sulfur.
Limestone or lime is only used when soils are very acid and do not have
Magnesium sulfate contains magnesium and sulfur.
Trace element fertilizers give the soil very small amounts of some elements,
e.g. iron, copper, manganese, molybdenum.
If a soil needs just one plant food, use a single fertilizer.
However, you can mix single fertilizers for several nutrients.
1. When applying fertilizers, first take away all weeds growing near
If a mulch has been used, rake this away and leave the soil bare.
2. Sprinkle the fertilizer evenly in a wide ring around the tree, but
do not put any of it close to the tree trunk.
Sprinkle fertilizer right out as far as drips of rain fall down from the
This is called the drip circle.
3. Rake the mulch back on top of the fertilizer.
Leave a clear space close to the base of the tree.
20.0 Harvest cocoa pods
See diagram 55.11: Harvesting
1. The harvesting of cocoa pods is very labour intensive.
On West African small-holdings the whole family, together with friends
and neighbours help out.
Ripe pods are gathered every few weeks during the peak season.
The high pods are cut with large knives attached to poles, taking care
not to damage nearby flowers or buds.
The pods are collected in large baskets, which workers carry on their
heads, and piled up ready for splitting.
The pods are split open by hand and the seeds or beans, which are covered
with a sweet white pulp or mucilage, are removed ready
to undergo the two-part curing process - fermentation and drying.
This prepares the beans for market and is the first stage in the development
of the delicious chocolate flavour.
2. The cocoa harvest can be spread over several months.
Although pods may be available for harvest throughout the year, usually
one or two peak harvest periods are used depending on
flowering in response to rainfall.
3. Ripe pods turn from green or deep red to yellow or orange.
Only the ripe pods are harvested but they can be left on the tree for
2 to 3 weeks.
Also, under ripe pods can be fermented.
Pod left too long on the tree will rot and the beans may germinate inside
4. Harvesting is by hand using machetes or knives to cut pods from the
Pulling the pods from the tree can damage the flower cushion and tear
5. After harvest, remove the approximately 40 beans from each pod by
breaking it open with a sharp blow, not with a machete, and
scooping the beans out by hand to form a pile, without damaging the beans.
This can be done immediately or delayed for a few days.
The plant placenta joining the beans inside the pod should be separated
from the wet beans before fermentation.
6. After about two years trees will start to make flowers and fruit.
Although fruits mature throughout the year, usually only two harvests
are made, e.g. in the Pacific islands, the ripe pods should be
harvested every two weeks between April and September and every four
weeks from September to March.
From fertilization to harvesting the fruit requires 5 to 6 months. Harvest
season lasts about 5 months.
Cut the pods from trees and store on the ground.
Crack the pods and remove the beans.
Burn the husks.
Production varies from 29 kg / ha to 2,000 kg / ha, 0.5 to 10 kg / tree.
21.0 Fermenting cocoa beans
See diagram: 55.21: Fermenting
1. Cocoa beans must be fermented and dried before being used as raw material
for making chocolate or cocoa.
At harvest, each pod containing 30-50 beans embedded in a slimy pulp is
cut open and the contents scooped out to form a tightly
packed mass that excludes oxygen gas and so allows anaerobic fermentation,
at first by wild yeast from the environment, mainly
The wild yeasts convert sugars to ethanol.
Also, lactic acid bacteria that are tolerant to ethanol convert sugars
and citric acid to lactic acids.
Yeasts also convert the pectin in the sticky pulp to a liquid to be drained
So air enters and allows aerobic acetic acid bacteria to oxidize ethanol
to acetic acid in an exothermic reaction to 45-50oC.
This temperature kills the yeasts, lactic acid bacteria and acetic acid
bacteria, so after 72 hours fermentation stops.
Acetic acid kills the embryonic seedlings and start the chemical reactions
that later produce colour, flavour and aroma after roasting.
2. During fermentation, the cocoa pulp clinging
to the beans matures and turns into a liquid, which drains away and the true
flavour starts to develop.
Fermentation methods vary considerably from country to country, but there
are two basic methods - using heaps and "sweating" boxes.
The heap method, traditionally used on farms in West Africa, involves
piling wet cocoa beans, surrounded by the pulp, on banana or
plantation leaves spread out in a circle on the ground.
The heap is covered with more leaves and left for 5-6 days, regularly
turned to ensure even fermentation.
In large plantations in the West Indies, Latin America and Malaysia, strong
wooden boxes with drainage holes or gaps in the slats in the
base are used, allowing air and liquid to pass through.
This process takes 6-8 days during which time the beans are mixed twice.
In Nigeria, cocoa is fermented in baskets lined and covered with leaves.
3. Fermentation develops chocolate flavour that
develops further during roasting of the beans.
Also, fermentation allows easy extraction of beans from the pod.
The wet beans are taken out of the pods then heaped to allow them to increase
temperature due to exothermic chemical reactions in the
pulp caused by the fermentation micro-organisms.
At first the sticky mucilage around the beans breaks down drains off as
After 36 to 72 hours the beans are killed by the heat and chemical changes
occur inside the bean and will continue during drying.
During fermentation the beans become darker and wrinkled and lose their
The beans are collected, heaped, covered with leaves and allowed to ferment
through the action of microbes and enzymes naturally
This process kills the germ of the bean, removes adhering pulp and modifies
the flavour and colour (now brown).
After drying, the beans are ready for export.
4. Fermentation can be done in wooden boxes about
800 kg capacity covered by banana leaves.
Usually at least 90 kg of beans are needed for processing for 5 to 7 days,
depending on the type of cocoa being grown and design of
the fermenting box.
The percentage of dry fermented beans to wet unfermented beans is called
It ranges from about 40% for under ripe pods to 45% for over ripe pods.
5. Make a fermenting box with some holes in it so
air can get in.
Ferment the beans 2 to 8 days before drying in sun.
Mix the beans every 2 days.
Test some beans to see if they are properly fermented.
Before fermenting the kernels inside are purple, but after fermenting
they are reddish brown.
2.1 Around each bean is a white, mucilaginous coating
that is sweet and tart to taste.
Its function is to provide a sugar source for the bean as it germinates
and for the fermentation process.
A traditional method was to put the beans in a hole covered with banana
leaves to trap the heat of fermentation.
Nowadays, the beans are put in fermentation boxes, "sweat boxes", soon
after removal because the beans begin to germinate as soon
as the fruit has been picked.
Too much germination cause a bitter taste in the chocolate.
Fermentation soon begins on exposure to air when spores from naturally
occurring yeasts, Saccharomyces sp., settle on the sugary
coating beans and convert the sugars into alcohol and carbon dioxide.
The alcohol is split further into acetic acid by vinegar bacteria,
2.2 On the first day of fermentation the temperature
may rise to 48oC.
If the fermentation temperatures is above 50oC, there is a
high risk of bad flavours in the beans.
With good management full fermentation of cacao beans can be achieved
without temperature rising above 46oC.
On the second day of fermentation, the temperature may reach 43oC,
where the germ within the cacao bean dies from the heat,
alcohol, and acetic acid to release enzymes within the bean to develop
the chocolate .flavour.
2.3 To control temperature, the pile must be kept
aerated during the first twenty four hours and lasting for the whole period
Rotate the beans in the sweat boxes by transferring the beans from one
sweat box to another.
If they are rotated too frequently, the beans get too much oxygen, become
too hot and develop dark spots.
If rotated too infrequently, the beans ferment unevenly, because the beans
in the interior of the sweat box will get less oxygen than the
beans at the sides.
When yeasts use up the oxygen in the pile, lactic acid bacteria are active.
When the pile is turned to aerate it, acetic acid bacteria convert the
alcohol produced by the yeast into acetic acid that breaks open
cells to allow all the cell contents to react with each other.
So astringent phenolic substances mix with other products of fermentation
to form less astringent substances.
2.4 Stacked sweat boxes, arranged like stairs, have
holes in the bottom for drainage and air circulation.
The beans are put in the sweat box at the top level and as the cocoa bean
fermentation continues shovelled to lower sweat boxes, until
they are removed from the bottom sweat box and dried.
Long sticks are used to break up clumps of beans and to stir the beans.
Sweat boxes with fitted steel frames can be filled and emptied with an
overhead hoist or modified fork lift.
Fermentation may take from two to eight days.
2.5 Fermentation alters the flavour of the seed
from being extremely acidic / tannic to developing softer flavours of fruit
precursors for chocolate flavour.
Polyphenol activity is reduced through fermentation.
Yeasts convert sugars to alcohol and metabolize some of the pulp acids.
Controlled inoculation of cacao seed fermentation using a Kluyveromyces
marxianus hybrid yeast strain in a well-aerated pile
improves the pectinolytic activity.
2.6 Digestive enzymes mix with storage proteins
and sucrose sugar to form simple sugars, which later form aromatic molecules
the roasting process.
Also, the beans soak up flavours from the fermenting pulp.
So during fermentation the astringent but bland tasting beans develop
desirable flavours and flavour precursors.
2.7 Fermentation brings out the very best flavours
and helps remove tannins that may be 5 - 15 % of the bean by weight.
Tannins cause an astringent flavour in the chocolate if not removed to
the final chocolate and must be removed.
2.8 Chocolate is still made from unfermented beans
in parts of Mexico and Central America for use in traditional dishes, but
chocolate from unfermented beans does not have the "body" and richness
as chocolate made from fermented beans.
Researchers have produced "starter cultures" to speed fermentation, produce
consistent flavours and improve yield and quality.
22.0 Drying, bagging and shipping
1. When fermentation is complete, the wet mass of beans is dried, either
traditionally by being spread in the sun on mats or using
special drying equipment.
When fermentation is finished the beans are dried in the sun or in ovens
to about 7% moisture to prevent the growth of undesirable
bacteria and moulds that may produce undesirable flavours.
The dried beans are then cleaned, bagged, and to cocoa manufacturers.
Artificial drying can cause beans to be very acidic if they are dried
Dried beans are hand sorted or mechanically sieved and winnowed to remove
defective beans and debris.
The number of pods required to produce 1 kg of dried beans is called the
Low pod index means good bean size and a high weight of beans per pod.
2. After fermenting the cocoa beans must be dried.
Building a good drier is quite hard, so try to find a drier that the school
The beans must be well dried and have only 6% moisture.
In most dryers heat comes from a wood fire, but the beans must not be
heated over 50oC and they must be stirred while they are
The beans are then bagged and shipped.
Further processing includes roasting, crushing, and separating out the
kernel, grinding the nibs and extraction of about half of the fat.
3. Quality of cocoa beans depends on flavour attributes,
average bean weight 1.0 to 1.2 g, bean count of 100 to 83 beans per 100 g,
low shell percentage of 11 to 17%, and fat content of the cotyledons
(nib) at least 53%.
4. In many countries, cocoa fermenters and cocoa
dealers and buyers are licensed to ensure production is at the standards
Inspectors of cocoa beans intended for export control quality of cocoa
The term "cacao bean" means the seed of the cacao trees (Theobroma
cacao L), which has not been passed through a fermentation
and drying process.
The term "cocoa bean" means a whole cacao bean that has been fermented
The term "cocoa processing" means the process of fermenting and drying
cacao beans for converting cacao beans into cocoa beans.
The term "fermenter, fermentary" means any place or premises maintained
for cocoa processing.
The term "dry cocoa" means cocoa beans that have been evenly dried and
the moisture content of which is not more than 8% and not
more than 1000 beans per kilogram.
The term "defective bean" means a cocoa bean that is either insect or
mite damaged or germinated, (shell has been pierced by the
seed germ) or flat (too thin) or coupled (beans stuck together).
The standard for "Export Cocoa" is based on accepted international standards
and is prescribed by local legislation.
Cocoa inspectors put inspection marks on cocoa bags for export.
They can check samples taken through the meshes of the bags by using a
5. In countries exporting cocoa beans, particularly
in West Africa, desiccant bags are placed inside the shipping containers
Addition of the desiccant bags inside the containers significantly reduces
the amount of condensation during the transit period.
The end result is a marked improvement of the quality of the cocoa beans.
After quality inspection the cured beans are packed into sacks for transportation
to where they will be processed.
On arrival at the factory, the cocoa beans are sorted and cleaned.
22.1 Chocolate and cocoa manufacture
The dried beans are cracked and a stream of air separates the shell from
the nib, winnowing.
The small pieces are used to make chocolate.
The nibs are roasted in special ovens at temperatures between 105-120oC.
The actual roasting time depends on whether the end use is for cocoa
During roasting, the cocoa nibs darken to a rich, brown colour and acquire
their characteristic chocolate flavour and aroma.
This flavour however, actually starts to develop during fermentation.
The roasted nibs are ground in stone mills until the friction and heat
of the milling reduces them to a thick chocolate-coloured liquid,
known as "mass".
It contains 53-58% cocoa butter and solidifies on cooling.
This is the basis of all chocolate and cocoa products.
The cocoa "mass" is pressed in powerful machines to extract the cocoa
butter, vital to making chocolate.
The solid blocks of compressed cocoa remaining after extraction (press
cake) are pulverized into a fine powder to produce a high grade
cocoa powder for use as a beverage or in cooking.
The cocoa mass, cocoa butter and cocoa powder are then quality inspected
and shipped to factories in Australia and New Zealand,
ready to be made into chocolate.
1.0 The chocolate manufacturer roasts the beans
to develop their flavour.
Roasting destroys harmful bacteria, and make cracking and winnowing easier.
Roasting and conching helps remove the tannins through oxidation and
Roasting causes chocolate flavour, as a result of Maillard or "browning"
reactions between amino acids and sugars.
At home roasting can be done in a microwave oven or roast for 5 minutes
at 150oC, then reduce to 120oC for ten minutes.
Preheat an oven to 350 degrees.
Roast an even single layer of beans for five minutes.
Lower the temperature to 250 during 15 minutes then maintain that temperature
until the beans are cracked, darker in colour and have
a cocoa smell.
Remove from the oven and leave to cool.
1.1 The shattered kernels of cacao are called nibs,
produced by a winnower that shatters the dry kernel and blows away the papery
skin or by hand peeling.
Hand sorting may be used to to remove bits of skin not removed from the
Remove the outer shell from the inner "nib." with a cocoa mill or by
1.2 Store nibs in an airtight container, out of
Cocoa nibs are about 55% fat, 60% saturated fat so chemically stable,
not prone to rancidity, and not damaged by high cooking
Cocoa butter is solid at room temperature.
Cocoa is a rich source of antioxidants, so resistant to rancidity.
1.3 Winnow the nibs to remove large chunks of leftover
husk with an electric fan.
The bits of husk are lighter then the nibs.
This takes some practice but left over bits of husk will be filtered out
in the juicer.
1.4 The nibs are ground into cacao paste with heat
to liquefies the oils and allows the paste to run freely and be refined by
milling or ball mill refining.
The paste is pressed to release the cacao butter leaving cake that is
broken up, pulverized and sieved to create cacao powder.
Grind the nibs in a juicer or household grinder until liquid cocoa drips
out the spout into a collection vessel.
1.5. The cocoa butter is cooled and formed to make
The cocoa cake is squeezed to make cocoa powder.
23.0 Pests and diseases
Cocoa is grown in places that are hot, moist and partly shaded that allow
many fungus diseases and pests to live.
Regularly examine the cocoa trees for signs of diseases and pests, and
then get advice from the Department of Agriculture on how to
The normally recommended methods for the control of capsids and black
pod disease, that involve mainly the use of conventional
insecticides and fungicides are now considered by many to be environmentally
unfriendly, posing a threat to both humans and
non-target insects, e.g. the midges that pollinate the cocoa flowers.
Some cocoa pests that occur in Papua New Guinea that do not occur in Bougainville
or the Solomon Islands.
You can find much information about pests and diseases from the internet
at websites run by Integrated Pest Management (IPM)
23.1.1 Cocoa capsid bugs (Hemiptera,
sub-order Heteroptera, Family Miridae) mirids, e.g. Helopeltis
sp., Distantiella sp.
See diagram 55.1.1: Capsid bugs
Capsids (Helopeltis or Distantiella) have not been recorded in the Solomon
Islands and they are not in Bougainville.
1. Capsids are sucking insects that feed mainly on the husk of cocoa
pods and young shoots of chupons and fans.
They use their piercing mouth parts to suck up sap.
Their feeding results in dark markings called lesions on pods, shoots,
petioles, leaf midrib and black angular spots on the leaf surface
caused by their toxic saliva.
Secondary damage of canker and dieback occurs when the lesions are invaded
by parasitic fungi, e.g. Calonectria and Fusarium
In very serious infection the entire tree looks burnt.
2. Capsids may occur at a break in the cocoa shade
canopy, followed by growth of vegetative chupons.
Feeding on fan branches results in damage to the tree canopy that causes
more damage to exposed cocoa in the dry season, called
3. The female adults lay eggs in the outer layer
of pods and beneath the bark of young shoots, then go through five nymph
stages for a
total incubation period of 2-17 days.
The adults are about 5.5 cm long.
The nymphs, are smaller and have no wings.
4. They can be controlled by spraying the plants
with an insecticide, e.g. "Gammalin 20" (Lindane) followed by a second spray
kill the bugs from eggs that were not killed by the first spraying.
However, the adverse side effects of persistent chemicals, including the
destruction of non-target beneficial insects, e.g. midges,
and their long lasting residual effects in the environment, make them
undesirable so some scientists want to replace Lindane.
Pesticide can be applied to mature cocoa with motorized knapsack mist
23.1.2 Cocoa weevil borer (Pantorhytes)
Pantorhytes biplagiatus (P. plutus) is damaging in the
This is probably the worst of all insect pests on cocoa.
This pest occurs in Papua New Guinea and in the Solomon Islands.
The adult weevils lay their eggs in small cracks in the bark of the cocoa
The small grubs that come out of the eggs bore holes into the trunk as
Some jelly like liquid comes out of these holes.
The grubs make holes right through the trunk and may go around and ring
bark the branch or trunk.
It is not much good trying to kill these insects with chemicals.
Collect the adult beetles by hand and kill them.
Get some Ikofala or "crazy ants" to come into the cocoa trees.
These ants make their nests in soursop trees, so planting some of these
trees will help to bring the ants into the cocoa.
The ants drive away the weevils.
The Pipturus plant attracts the cocoa weevils.
Ask the agricultural officer to show you these plants so you can destroy
23.1.3 Amblypelta cocophaga
The body is about 20 mm long, the legs are pale green, while the wings
are pale brown.
Females lay eggs on or near the host plant.
Nymphs hatch a few days later.
They are dark brown with long legs and antennae; they look like adults
Nymphs feed in the same way as adults, and on the same plants using needle-like
It is not known if nymphs inject poison, but it is likely.
Wings develop when nymphs become adult, 3-4 weeks after emerging from
They are brown or green bugs about 2 cm long.
They have very long feelers, but in the young bugs the feelers are thick.
The young and old bugs feed on cocoa pods and young shoots.
They suck juices up through long thin feeding tubes.
If they feed on young pods, the whole pod may be spoiled, and young shoots
may be killed.
These bugs also attack coconut trees and make the young nuts fall of the
Spray the pods with the same spray used to kill capsids.
Get some ikofala ants into the cocoa trees by planting soursop trees among
the cocoa trees.
It is a minor pest but can be controlled with crazy ants.
Also, the fire ant, Wasmannia auropuntata, can protect palms against
See diagram 55.1.4: Termites
No termites are listed as pests by CABI.
Termites or "white ants" are ants that live by eating holes in wood.
They may weaken a branch or a trunk so much that it falls over.
It is often hard to tell whether the termites are in a tree, because they
make holes just under the bark and there may be no signs outside.
Treatment may include the following:
1. If an attack is found, the branch can be cut off close to the main
2. If a nest is found, it can be opened a little and a bottle full of
weak chlordane (0.2%) mixture poured into it.
3. Slowly pour "Dursban" (Chlorpyrifos) solution at the base of each
23.1.5 Longicorn beetles (long
antennas beetles), e.g. Glenea lefebueri
See diagram 55.1.4: Longicorn beetles
The longicorn beetle (Family Cerambycidae) Glenea aluensis occurs
in the Solomon Islands, although neither G. aluensis nor
G. lefebueri are listed by CABI.
They are associated with poorly managed cocoa under heavy shade or near
Be sure that they are economically important before any control because
control is very difficult.
These pests are big beetles with long feelers.
The beetles are either bright yellow or bright blue.
The grubs of these beetles are pale yellow in colour and have strong jaws.
The beetles lay their eggs on the trunk.
The grubs hatch out and eat holes in the soft part of the trunk.
The trunk may be ring barked and die.
Signs of this grub may be seen as lumps of wood chips stuck together in
rusty coloured lumps.
These are pushed out and breathing holes made by the grubs.
The fungus causing the tree canker may get into the tree through these
The way to kill these grubs is to open some holes and pour in an insecticide.
This can be made up by mixing together: 12 litre of Lebaycid, 4 litres
of white oil, 12 litres of water 16 mL wetting agent.
23.1.6 Giant African Snail
(GAS) (Achatina fulica)
1. The snail can kill young cocoa seedlings and damage cocoa trees.
It can feed on leaves and tubers of many types of crops.
2. It searches for food at night and hides in the soil during daytime.
The eggs are 5 mm diameter, round and white are usually found in batches
of about 200 eggs just beneath the soil surface.
The eggs hatch within 15 days after laying.
3. It was introduced from East Africa and is now established in some
Pacific islands, but not been reported from Cook Islands, Fiji,
Kiribati, Nauru, Niue, Pitcairn Island, Solomon Islands, Tokelau and
It can be easily transported between countries in containers, machinery
and empty bottles.
After it has become established, it is extremely difficult to eradicate.
Villagers should collect the snails and kill them by burning or immersing
in sea water.
Clear rubbish and weeds in infested areas to reduce breeding places.
Do not bring planting materials from infested areas to places where the
snail is not present.
4. The best way to control Giant African Snail is to eat them.
The snail can be controlled with chemical baits, e.g. Blitzem, Esbit,
Canned Heat (metaldehyde) fuel tablets and snail bait, mixed with
sawdust and cement.
However, but baits may be dangerous if eaten by students or domestic
See diagram 55.1.7: Poison baits for rats
Rats may do much damage to cocoa pods, because they eat holes in the
outside of the pods so they can eat the soft part inside.
A good way to stop rats is to put wax blocks containing brodifacoum into
bamboo tubes and tie these on to the branches of the tree.
Another thing to do is to get some crazy ants or ikofala ants into the
These ants keep the rats away.
Whatever you do to control rodents it is essential that measures are carried
out on an area wide basis, one farmer trying to control
rats is useless.
23.1.8 List of insect pests
of Cocoa in Solomon Islands
from CABI Crop Protection Compendium CD
Achatina fulica (giant African land snail)
Ahasverus advena (foreign grain beetle)
Amblypelta cocophaga (coconut bug)
Aphis craccivora (groundnut aphid)
Aphis gossypii (cotton aphid)
Aspidiotus destructor (coconut scale)
Brevipalpus phoenicis (false spider mite)
Ceroplastes destructor (white wax scale)
Corcyra cephalonica (rice meal moth)
Dysmicoccus brevipes (pineapple mealy bug)
Euwallacea fornicatus (tea shot hole borer)
Ferrisia virgata (striped mealy bug)
Homona coffearia (tea tortrix)
Leptoglossus gonagra (squash bug)
Nezara viridula (green stink bug)
Pantorhytes (weevil borers)
Planococcus minor (passion vine, mealy bug)
Rhynchophorus bilineatus (black palm weevil)
Selenothrips rubrocinctus (red banded thrips)
Spodoptera litura (taro caterpillar)
Tenebroides mauritanicus (cadelle)
Toxoptera aurantii (camellia aphid)
23.1.9 Insect pests of cocoa
in Papua New Guinea, importance and control
J. E. Moxon, Department of Agriculture and Livestock, Papua New Guinea
Many insects feed on cocoa, attacking most parts of the tree in both
the establishment and production phases.
Crop losses range from most serious to slight depending on insect type,
density, distribution, occurrence and duration of attack.
Many serious pests are absent from the North Solomons Province, Papua
New Guinea, which produces about half of the country's
An integrated approach to control is preferred because of a wide variety
of pests and their natural enemy complexes.
Both large estate and smallholder sectors produce large amounts of cocoa
though their farming methods are generally very different,
the former having a much higher technical, financial and management input
than the latter.
It is often necessary to provide different pest control recommendations
to suit the two farming sectors.
Many smallholder blocks either begin as or, more usually, become mixed
gardens containing coconuts, areca palms, bananas and
fruits, nuts and food crops.
Some pest associations between these crops and cocoa in the farming system
and between shade trees and cocoa are considered and
the value of coconut as a shade for cocoa is highlighted.
Cocoa is the most important cash crop in the lowland areas and large
scale redevelopment of over mature cocoa and development in
new regions using high yielding Trinitario x Upper Amazon hybrid material
is expected to increase production significantly over the
next few years.
Many factors, e.g. climate, soils and marketing, favour cocoa production
in the major cocoa growing regions, but pests, diseases and
poor management can impose serious constraints.
Pantorhytes weevils, caterpillars and vascular streak dieback can cause
the collapse of the industry in a major regions.
Over 300 species of pests have been associated with cocoa in Papua New
However, only about 10 pests regularly cause widespread, economic damage.
Damaging Pantorhytes weevil species, mirids, and some other pests for
example are believed to be absent from North Solomons\
Province, Papua New Guinea, an island that produces half of the country's
Main insect pests of cocoa in order of economic importance
Group 1. (the worst pests)
Wood boring Pantorhytes beetle larva (Coleoptera: Curculionidae) Larvae
bore into wood of trunk and main branches.
Leaf eating caterpillars (Lepidoptera: Limacodidae) (Lepidoptera: Noctuidae)
(Lepidoptera: Geometridae) Larvae eat both young
and mature leaves.
Wood boring longicorn beetles (Coleoptera: Cerambycidae) Larvae bore
into wood of trunk and main branches.
Pod damaging mirids (Hemiptera: Miridae) Adults and nymphs suck sap from
pods and shoots.
Group 2. Shoot chewing Grey weevils (Coleoptera: Curculionidae) Adults
chew bark on shoots of young cocoa Terminal branch\
Pansepta moths (Lepidoptera: Xylorictidae) Grubs bore in branches Wood
eating termites (Isoptera: Kalotennitidae) Adults and
nymphs chew wood inside the tree.
Group 3. Pod sucking bug Amblypelta (Hemiptera: Coreidae) Adults and
nymphs suck sap from pods.
Root chewing Chafer beetles (Coleoptera: Melolonthinae) Larvae chew roots
of young trees.
Mealy bugs (Hemiptera: Pseudococcidae) Adults and nymphs suck sap from
shoots, pods and flowers,
Tip boring Oxymagis (Coleoptera: Cerambycidae) Larvae bore into terminal
Pod Borers (Lepidoptera: Tortricidae) (Lepidoptera: Olethreutidae) Larvae
bore into husk of pods.
Leaf eating Rhyparids (Coleoptera: Chrysomelidae) Adults eat leaves.
Stem boring Zeuzera moths (Lepidoptera: Cossidae) Larvae bore into wood
of trunk and main branches.
The economic importance of an insect is ultimately measured in terms
of crop loss.
This can be a direct result of feeding on pods or indirect result of feeding
damage on other parts of the tree.
The major pests in Papua New Guinea attack many parts of the tree including
pods, leaves, shoots, branches, trunks and roots.
Both young and mature cocoa are attacked and so pest control is often
necessary throughout the life of the crop.
Pests that damage young cocoa may either stunt or kill the tree necessitating
replanting or retard growth all of which reduce time to
bearing and thus result in a measurable crop loss.
Pests that attack the wood of mature trees can cause senility or death
and so are particularly important.
The insect type, density, distribution, occurrence and duration of attack
contribute to the overall importance of a pest.
Pantorhytes species are now possibly the worst pest of cocoa in Papua
Pantorhytes species occur in New Guinea, the Bismarck Archipelago and
the Solomon Islands, with species extending to Queensland
In the North Solomons Province, Papua New Guinea, which produces half
the country's cocoa,
P. biplagiatus is scarce and never of economic importance while
the same species in the neighbouring Solomon Islands can be most
Pantorhytes species are robust, heavily sclerotized, wingless weevils
about 1-5 cm long.
The eggs, which are white, ovoid and about 2 mm long, are laid singly
in crevices on the trunk and main branches, particularly near the
jorquette, intersection of main branches and tree base.
Eggs hatch after 2 to 3 weeks.
The larva has a well developed brown head and curved cream body with rows
of fine hairs.
The larva bores into the wood 1 to 2 cm deep and feeds on sap wood making
tunnels or channels parallel to the surface.
The larva feeds for 3 to 9 months through 9 instars and then pupates beneath
the bark in about 14 days.
The newly emerged adults feed for 4 to 6 weeks before mating, after which
time the female lays about 2 eggs per day sometimes
through out her life span of one to two years.
Adults feed mainly on the semi-hardened bark of young cocoa shoots and
occasionally on pod husks, leaves and flowers though
damage is rarely economic.
Larval feeding, by contrast, is usually devastating.
The larvae bore into the sapwood of trunks and main branches of trees
more than about two and a half years old, causing structural
weakness, tip dieback and a general canopy degradation, branches may
be ring barked and die and trees may split at the jorquette.
A severe drop in production follows and often a large proportion of the
Wounds made by larvae in the bark are an entry point for bark canker,
Phytophthora pabnivora, which also reduces yield and kills
Termites may also enter the tree as secondary pests.
Pansepta larvae are most damaging on young trees when they bore
into or ring bark the main branches.
However, since about the beginning of 1987 Pansepta has been particularly
abundant in New Britain and large areas are suffering
from severe tip dieback, including main branches, canopy degradation
and crop loss.
The pest is easily controlled on young trees by removing the web and applying
dimethoate, a systemic insecticide, onto the bark with a
brush or swab but there is no economic control recommendation for Pansepta
on mature trees.
Pansepta is usually only a problem on lightly shaded cocoa although
since 1987 the pest has been reported throughout well shaded
Several species of termite attack cocoa in Papua New Guinea.
The most important species is the giant termite, Neotermes papuana
that occurs throughout the islands region and is particularly
damaging in New Britain, Papua New Guinea.
Termites first enter the tree via dead branches and then make their nest
in the living wood and feed it.
The tree canopy is reduced, production falls, branches die and eventually
the tree is killed.
Termites are easily controlled by exposing part of the nest and pouring
a dilute solution of insecticide into it.
The newer pyrethroids give a good kill and are safe to use.
Neotermes papuana does not construct covered runways on the tree,
but the location of the nest is indicated by a water-soaked
appearance on the bark.
Some shade trees are also attacked by termites and so these must also
be inspected regularly and treated.
Termite infestations can be prevented to some extent by pruning dead branches
from the tree.
A number of species have been noted feeding on cocoa but only Amblypelta
theobromae and Amblypelta cocophaga are pests.
Amblypelta theobromae can cause large crop losses on mainland Papua
Adults and nymphs suck the sap from pods and shoots causing damage similar
The life cycle takes about 6 weeks.
A. cocophaga occurs in the North Solomons and Solomon Islands where
it is an occasional pest of cocoa.
The ant Oecophylla smaragdina is negatively associated with both
Amplypelta is controlled in the same way as mirids
Chrysomelid beetles of the genus Rhyparida, which feed on the
flush leaves of cocoa can build up rapidly and cause extensive
There are many species of Rhyparida distributed throughout Papua
Eggs are laid on the ground and the larvae feed on plant roots.
Pupation also occurs in the ground and the life cycle takes about 6 weeks.
Defoliation can be prolonged and particularly damaging when associated
with dry weather.
It is often necessary therefore to control Rhyparida on cocoa trees
up to about 2 years old using insecticides.
Two pod boring moths, Cryptophlebia encarpa and Olethreutes
sp. are minor pests of cocoa in Papua New Guinea and the
Eggs are laid singly on the pod surface.
The larvae hatch within 24 hours and burrow into the epicarp of the pod
husk to feed.
The larvae feed for 13 to 15 days.
23.1.10 Insect pest control
1. Biological control using crazy ants
Although over 30 parasites predators and pathogenic fungi have been recorded
from Pantorhytes, none have shown promise as
biocontrol as the crazy ant, Anoplolepsis longipes and possibly
Dense crazy ant populations eliminate Pantorhytes from cocoa,
but as the ant density decreases so the Pantorhytes reinvade and
A technique has been developed for collecting and introducing crazy ants
The crazy ant also controls some other cocoa pests.
Present work is attempting to develop methods of stabilizing crazy ant
populations, which are sometimes transient.
2. Hand-picking of adults
Adults weevils are easily seen, collected and destroyed by hand during
the middle of the day when they descend through the canopy to
This method is popular with smallholders who operate on restricted budget
and some large estates also find the method cost effective
when operating on a "bounty payment system".
3. Larval channel paints
Larvae are easily detected in the tree by the presence of frass expelled
from the entrance hold of the larval channel.
The frass is removed with a stiff brush and the larvae are then easily
killed by applying a solution (channel paint) of Dichlorvos, White
Oil, Ridomil and water with a small 2 cm brush onto the bark around the
About 80% of larvae treated in this way die.
Ridomil is added to the channel paint to control any Phytophthora
that might be present.
It is recommended that trees severely infested with Pantorhytes
larvae be inspected and treated at least every two weeks.
4. Coconut shade
Pantorhytes populations are often, but not always, low in cocoa
grown beneath coconut shade although the reason for this is unknown.
One possible explanation is that coconuts often harbour Oecophylla
smaragdina ants, which are believed to repel Pantorhytes.
By contrast, cocoa grown beneath other shades such as Leucaena
and Gliricidia is often badly damaged by Pantorhytes.
For this reason it is strongly recommended that coconuts be used as a
shade for Pantorhytes are believed killed by natural enemies
before they enter the wood.
The larva constructs a silk web mixed with brown droppings or frass over
the feeding area for protection.
Larvae feed on wood and bark for 8 to 12 weeks.
Pupation takes 3 to 4 weeks and adults live for only a few days.
23.2.1 Black pod disease (Fungi:
Phytophthora palmivora, Phytophthora megakarya)
See diagram 55.2.1: Black pod disease
1. This is a common disease of cocoa.
The signs of the disease are that black patches appear on the pod, usually
down near the tip first.
The black patches gradually spread upwards and soon the whole pod and
the beans inside it are rotten.
This disease is caused by a fungus that grows very fast in cool wet weather.
The body of the fungus is like fine white threads of cotton.
It makes spores that get into drops of rainwater on the outside of the
Then they can be splashed onto healthy pods of trees nearby.
These are the things that can be done to stop this
1. Pick the ripe pods regularly every one or two weeks.
2. Take all diseased pods off the tree and carry them away from the cocoa
trees and burn them.
Do not touch healthy pods after touching diseased pods or you may spread
the spores that cause the disease.
3. Do not open ripe pods near the cocoa trees.
The disease may grow on the old pods left lying nearby.
4. Cutting down some trees around the cocoa trees and so increase the
flow of air through the trees may be possible.
This may make the air drier and not such a good place for the fungus spores
5. Protect apparently healthy pods with copper based fungicides, with
or without metalaxyl.
If more than one third of the pods get black pod disease, then a spray
must be used or the disease will spread to all the pods.
To make the spray mixture put half a kilo of blue stone (copper sulfate)
into 4 litres of water and stir until it is dissolved.
In a separate bucket put half a kilo of slaked lime (hydrated lime) into
4 litres of water and stir until it is dissolved.
Pour the blue stone solution and the lime solution into a 20 litre container.
Stir this mixture well.
Spray this mixture until the spray is dripping off the pods.
Also, spray the leaves above the pods and on the trunk.
This spray must be used the same day as it is mixed, not later.
6. In Papua New Guinea trunk injection with potassium phosphonate significantly
reduced Phytophthora pod rot and increased pod
Use of potassium phosphonate or phosphorous acid does not contaminate
7. The disease may be spread by ants, beetles, the pod borer Characoma,
and infected pods and pod husks.
Some pest control results from frequent harvesting, immediate removal
of infected pods and establishment of ground cover.
Selection and breeding of cocoa varieties for resistance to black pod
may be possible.
23.2.2 Bark Canker (Ceratocystis
See diagram 55.2.1: Bark canker
The bark has been peeled off the trunk to show the canker spreading around
This disease attacks the trunk and branches of the cocoa tree.
If a tree has the canker, the bark may have patches of darker colour.
Also, a reddish brown liquid may come out of the bark and turn a rusty
brown colour when dry.
Insects live in the dying bark and may make any holes in it.
When the bark is cut away, you can see the canker.
This disease is caused by the same fungus that causes black pod.
Always put tar over a cut made when pruning a tree.
Pruning tools must be sterilized by dipping them in a 1% sodium hypochlorite
Take all black pods away because they carry the canker spores.
In small cankers, cut away the bad bark, making a clean cut just outside
23.2.3 Dieback (Vascular streak
dieback virus, VSD)
See diagram 55.2.3: Dieback disease
In this disease the top branches of a tree die.
The disease starts when leaves turn yellow and drop off.
What causes this disease is not known but it may be a virus carried by
Make sure the trees have the right amount of shade.
Trees that do not have enough shade may get dieback.
Look at the leaves of the trees.
Observe whether they have brown leaf edges, or yellow leaves or leaves
with light green patches between leaf veins.
These things may mean that the trees are not getting enough minerals,
and they may need some fertilizers.
Kill insects on the trees.
If many leaves are killed the tree may get dieback.
Prune off the dead branches, and cover the cut ends of branches with tar.
23.2.4 Pink Disease (Botryobasidium
See diagram 55.2.3: Pink disease
In this disease a fungus attacks the branches of cocoa trees.
It also attacks branches of other trees like coffee, citrus or rubber
The first sign is when fine white threads of fungus are seen on a branch.
Later the fungus forms a pink crust over the branch.
By the time the leaves drop off the tree and the branch will soon die.
To stop this disease:
1. Cut off the diseased branches making the cuts 45 cm below the bad
2. Take the bad branches away and burn them.
3. Put some tar or other chemical fungicide over the cut you have made
on the tree.
23.2.5 Thread Blight (Corticium
incisum, Marasmius species, and other species)
See diagram 55.1.1: Thread blight
Seeing this disease is easy if it comes to your tree, because the leaves
have fungus threads growing thickly over them.
Sometimes the threads are white and sometimes they are a dark colour.
The threads are quite thick. This disease makes the leaves die and grow
Cut out the diseased branches and burn them.
23.2.6 Witches' broom disease
The fungus Moniliophthora perniciosa, (Crinipellis perniciosa),
(Basidiomycetes, euagarics clade), causes witches' broom disease,
attacking species of Theobroma and Herrania.
It has caused devastation for 20 years to major cacao-farming regions
in South and Central America.
It can disrupt hormonal balance, provoking hypertrophy and hyperplasia
followed by tissue necrosis.
The intercellular mycelium is typically swollen and convoluted.
The life cycle, including mode of reproduction, have yet to be resolved.
Initial infection by Moniliophthora perniciosa basidiospores occurs
in actively growing cacao meristems, causing a characteristic
disorganized proliferation of new shoots in the host called "witches'
Potential crops are lost when clusters of flowers produced on "cushions"
on the main trunk and older branches are infected, thus
producing seedless strawberry-shaped or carrot-shaped fruits.
Also, Moniliophthora perniciosa attacks cacao pods in the early
stages of development, penetrating the husk and destroying the
seeds from which chocolate is derived.
After death of the broom tissue, fructification of small pink agarics
However, increased exports are expected from Brazil where production
is expected to recover from the loss caused by the witches'
23.2.7 Frosty pod rot of cacao
Frosty pod rot has a limited geographic range but unlimited potential
Moniliophthora roreri, an anamorphic ascomycete, the cause of frosty
pod rot, (moniliasis disease), is a specialized fungal pathogen
(family Marasmiaceae) that invades only actively growing pods of cacao,
Theobroma cacao, and related species of Theobroma and
Frosty pod rot damages pods and the commercially important seeds that
some of these species produce.
Moniliophthora roreri was confined to northwestern South America
until the 1950s.
Its appearance in Panama in 1956 signalled a change in its geographic
Now, it is found in 11 countries in tropical America.
The fungus is currently in an active dispersal phase, possibly due to
an increase in human-mediated spread.
Frosty pod rot is more destructive than black pod (Phytophthora
spp.) and more dangerous and difficult to control than witches'
broom, caused by Moniliophthora (Crinipellis) perniciosa.
The aggressiveness of Moniliophthora roreri, its capacity to survive
different environmental conditions, its rapid natural dispersal, its
propensity for man-mediated dispersal, and the susceptibility of most
commercial cacao genotypes, all indicate that frosty pod rot
presents a substantial threat to cacao cultivation world wide.
In Costa Rica, frosty pod rot forced farmers to switch to other crops,
25.0 Returns, costs and profits
See 188.8.131.52: Understanding
You grow cocoa so that the beans can be fermented and dried properly
and then sold for money, so calculate the annual profit of the
Returns means all the moneys they have received from selling the cocoa.
Cocoa pods ripen at different times, so the beans must be fermented and
dried at different times and the money received for the beans
will come in at different times.
Record the returns under the 3 headings: Date Amount Sold (Profits =
Returns - Costs).
However, costs are divided into two groups.
Establishment costs are moneys paid for things that will last more than
a year, e.g. a spade and secateurs.
So you add these costs and divide them by the number of years that you
think these things will last, e.g. Divide by 3 if you think the
items can be used for 3 years.
This calculation gives us a figure for establishment costs for each year.
Production Costs are costs for things that you must buy every year, e.g.
fertilizers, fungicides and insecticides.
So (profits = returns - (establishment costs / 3) - production costs)
Net profit for the year = total profit of the 40 cocoa trees / 40, i.e.
profit per tree. you can also calculate profit / hectare (ha).
Cultivation of recommended new hybrid cocoa cultivars should bring higher
yields and profits.
28.3.0 "Scientists put cocoa
under the microscope"
Friday, 27 June 2008 Matt Sedensky (edited for this website)
Scientists are launching a five-year project aimed at safeguarding the
world's chocolate supply by dissecting the genome of the cocoa
The team of scientists from the US Department of Agriculture (USDA), will
analyse the more than 400 million parts of the cocoa
It hopes the process will lead to better-tasting chocolate and help battle
crippling crop diseases, estimated to cost cocoa farmers an
estimated US$ 700 million annually.
The analysis will not only identify what traits make cacao trees susceptible,
but it will allow scientists, and chocolate manufacturers, to
better understand every aspect of cocoa, from its ability to sustain
drought to the way it tastes.
"Once we have the whole genome, (manufacturers) will be able to go in
and look at all the genes they're interested in," says Dr Ray
Schnell, a research geneticist with the USDA.
"They'll all be interested in flavour genes."
The project's backers say the work stands to be a boon to farmers, largely
in Africa, who produce about 70% of the world's cocoa.
By determining which breeds of cacao trees are most appropriate for a
specific locale and most able to fend off disease and drought,
farmers could increase crop yields.
An IBM team will participate in the cocoa efforts.
Though the project is funded by chocolate manufacturer "Mars", its findings
will be made public, even to its competitors.
Mars says there will be more information to examine than any one company
could ever do alone, and that the main reasons for
cracking the genome are to combat cocoa pests and disease.
"For us, the fact that Hershey has similar information that every other
chocolate company in the world has, that's fine," says
Howard-Yana Shapiro, Mars' global director of plant science.
Shapiro says he did not expect improvements in yields from research would
lead to larger overall cocoa crops.
He says higher yields would allow farmers to devote some of their land
to other lucrative crops that could boost their income.
While very little cocoa is produced in the United States or Australia,
its production has a flow-on effect for many domestically
produced items, e.g. raisins, almonds and macadamia nuts.