School Science Lessons
Please send comments to: J.Elfick@uq.edu.au
Table of contents
See websites: Cocoa
1.1 History and Importance of cocoa, (Primary)
1.2 Cocoa shade trees, (Primary)
1.3 Cocoa planting, (Primary)
1.4 Care of cocoa plants, (Primary)
1.5 Harvesting and fermenting cocoa, (Primary)
1.6 Pests and diseases of cocoa, (Primary)
2.0 Where cocoa will grow, (Primary)
3.0 Parts of a cocoa tree
6.0 Seeds in the pod
7.0 Pollination and fertilization
8.0 Cocoa pod
10.0 Make a seed bed
11.0 Choose and plant seeds
12.0 Varieties of cocoa
13.0 Soils for cocoa
14.0 Prepare land for cocoa
15.0 Shade trees for cocoa
16.0 Transplant cocoa
17.0 Mulch and weed cocoa
18.0 Prune the cocoa tree
19.0 Fertilizers for cocoa
20.0 Harvest pods
21.0 Fermenting cocoa beans
22.0 Drying, bagging and shipping beans
22.1 Chocolate and cocoa manufacture
23.0 Pests and diseases
25.0 Returns, costs and profits
27.0 Commercial chocolate
28.0 Chocolate recipes
28.1.0 Home-made chocolate
28.2.0 Aztec "Cacahuatl"
28.3.0 "Scientists put cocoa under the microscope"
Pests and diseases
23.1.1 Cocoa capsid bugs, Helopeltis, Distantiella
23.1.2 Cocoa weevil borer, Pantorhytes
23.1.3 Amblypelta cocophaga
23.1.5 Longicorn beetles, Glenea lefebueri
23.1.6 Giant African snail, Achatina fulica
23.1.8 List of insect pests of Cocoa in Solomon Islands
23.1.9 Insect pests of cocoa in Papua New Guinea
23.1.10 Insect pest control methods
23.2.1 Black pod disease, Phytophthora palmivora
23.2.2 Bark Canker, Ceratocystis fimbriata
23.2.3 Dieback, vascular streak dieback virus
23.2.4 Pink disease, Botryobasidium salmonicolor
23.2.5 Thread blight, Corticium incisum
1.0 Introduction to the cocoa
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
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 properly.
Cocoa is produced in tropical countries, but is processed and consumed in
2. Cocoa grow best under the canopy of tropical rainforests, seldom reaching
more than 7.5 m hight. They need to be shaded from
direct sun and wind, particularly in the early growth stages. The cocoa tree
has broad, dark leaves about 25cm 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.
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. 2. Alternatively, forest
trees are thinned out and the cocoa trees are planted between established
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 flavour. 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. Trinitarios are hybrids of a Criollo and Forastero, and have intermediate
qualities. 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% water.
3.0 Parts of a 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 shoots. It has spreading branches, stipules
5 to 14 mm long, large green leaves with petioles. 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 base? 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 ground. 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.
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.
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 flower. 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 five petals. 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 fallen flowers.
6.0 Seeds in the pod
See diagram 55.6: Seeds in the pod | See diagram 55.4: Cocoa 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 450gms 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 wood.
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 shaken.
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 is pollinated. 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 tree. 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, golden-orange colour.
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 the pod. If the pod
is ripe, the gum of the seeds will be slippery and it will taste sweet.
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 pulp.
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.
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 seed leaves. 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 Make a 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 Choose and plant seeds
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 and grow.
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
is cheaper. 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 and performance. 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
downwards. 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 leaves. 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 be smooth. The ripe pods are green or
yellow, and the wall of the pod is very thick and woody. 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 Forastero types.
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 islands. 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 well. 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 since 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. Soils. 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
with the water repeated digging to the same level just below the surface.
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 tokeep 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 much
shade. 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 shade.
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 shade trees.
2. Dig trenches one metre long in between the cocoa, or plant Leucaena
seeds in strips or one metre long between cocoa planting places. Mark out
strips of soil one metre long between the stakes where cocoa seedlings will
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 to 50%. 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
16.0 Transplant cocoa
See diagram 55.16: Dig a hole for cocoa a month
before planting | 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 research centre.
A few hours before lifting the seedlings from the nursery beds, water the
soil. 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 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 tap-root.
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. helps to keep the surface
of the soil moist and cool. In cold weather it keeps the soil warm, 2.
protects the soil and stops heavy rain washing away the topsoil, 3. helps
to keep sun off the weeds and stops their growing,
4. keeps the surface of the topsoil soft and moist, 5. contains some
nutrients, plant foods, which can be washed down into the soil.
However, in a dry climate with only occasional light rain, too much mulch
may absorb all the rainfall so that no moisture reaches the plant roots.
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 lines. 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 grow again.
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 easy 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
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
the stem. 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
Some common fertilizers:
Urea: This 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: This 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: This 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.
Some of these fertilizers give the soil iron, or copper, or manganese, or
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
the trees. 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 leaves. This is called the drip
3. Rake the mulch back on top of the fertilizer. Leave a clear space
close to the base of the tree.
20.0 Harvesting 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 the pod.
4. Harvesting is by hand using machetes or knives to cut pods from the
tree. 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. During fermentation the cocoa pulp clinging to the beans matures and turns
into a liquid, which drains away and the true chocolate 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.
2. 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 "sweatings". 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 bitter taste. The beans are collected,
heaped, covered with leaves and allowed to ferment through the action of
microbes and enzymes naturally present. 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.
3. 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 "recovery". It ranges from about 40% for under ripe pods
to 45% for over ripe pods.
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, "sweatboxes",
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, Mycoderma aceti.
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 of fermentation. Rotate
the beans in the sweatboxes 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 sweatbox at
the top level and as the cocoa bean fermentation continues shovelled to lower
sweatboxes, until they are removed from the bottom sweatbox and dried. Long
sticks are used to break up clumps of beans and to stir the beans. Sweatboxes
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 and the 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
2.6 Digestive enzymes mix with storage proteins and sucrose sugar to form
simple sugars, which later form aromatic molecules during 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
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
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.
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 too quickly. 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 "pod index". 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 could use. 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 being dried. 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
4. In many countries cocoa fermenters and cocoa dealers and buyers are
licensed to ensure production is at the standards of export cocoa. Inspectors
of cocoa beans intended for export control quality of cocoa beans.
The term "cacao bean" means the seed of the cacao trees (Theobroma
cacao L) which has not been passed through a fermentation and drying
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 stab sampler.
5. In countries exporting cocoa beans, particularly in West Africa, desiccant
bags are placed inside the shipping containers with the cocoa beans. 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 105-120 degrees Celsius.
The actual roasting time depends on whether the end use is for cocoa or chocolate.
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 (presscake) are pulverised 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 other
processes. 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 kernel.
Remove the outer shell from the inner "nib." with a cocoa mill or by hand
1.2 Store nibs in an airtight container, out of direct sunlight. Cocoa
nibs are about 55% fat, 60% saturated fat so chemically stable, not prone
to rancidity, and not damaged by high cooking temperatures. 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 stone 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 chocolate.
1.6. 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 control them. 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.,
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 species. 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 "capsid blast".
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 time to 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 blowers.
23.1.2 Cocoa weevil borer (Pantorhytes)
Pantorhytes biplagiatus (P. plutus) is damaging in the Solomon
Islands. 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 tree. The small grubs
that come out of the eggs bore holes into the trunk as they grow. 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 them.
23.1.3 Amblypelta cocophaga
It is a minor pest but can be controlled with crazy ants. 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 tree. 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.
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 forests. 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 holes. 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 Tonga. 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 children or domestic animals.
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 cocoa area. 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 cocoa.
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 Guinea). 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 cocoa.
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.
Shoot chewing Grey weevils (Coleoptera: Curculionidae) Adults chew bark
on shoots of young cocoa Terminal branch feeding. Pansepta moths (Lepidoptera:
Xylorictidae) Grubs bore in branches Wood eating termites (Isoptera: Kalotennitidae)
Adults and nymphs chew wood inside the tree.
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
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
New Guinea. Pantorhytes species occur in New Guinea, the Bismarck Archipelago
and the Solomon Islands, with species extending to Queensland in Australia.
In the North Solomons Province, Papua New Guinea, which produces half the
country's cocoa, P. biplagiatus is scarce and never of economic importance
same species in the neighbouring Solomon Islands can be most damaging.
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
more than about two and a half years old, causing structural weak ness,
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 plantation dies. Wounds made
by larvae in the bark are an entry point for bark canker, Phytophthora
pabnivora, which also reduces yield and kills trees. 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 plantings.
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 New Guinea.
Adults and nymphs suck the sap from pods and shoots causing damage similar
to mirids. 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 species. 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 defoliation.
There are many species of Rhyparida distributed throughout Papua
New Guinea. 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 Solomon Islands.
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 Oecophylla smaragdina.
Dense crazy ant populations eliminate Pantorhytes from cocoa but
as the ant density decreases so the Pantorhytes reinvade and increase.
A technique has been developed for collecting and introducing crazy ants
to cocoa. The crazy ant also controls some other cocoa pests. Present work
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 cooler places.
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 entrance hole. 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 and other considerations
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 pod.
Then they can be splashed onto healthy pods of trees nearby. These are the
things that can be done to stop this disease: 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 to grow.
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
6. In Papua New Guinea trunk injection with potassium phosphonate significantly
reduced Phytophthora pod rot and increased pod yield. Use of potassium phosphonate
or phosphorous acid does not contaminate the environment.
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
the trunk. 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 solution. 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 the canker.
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 mealy bugs. 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 trees. 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 part. Take
the bad branches away and burn them. 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 brown. Cut out the diseased branches
and burn them.
25.0 Returns, costs and profits
See 126.96.36.199: 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 cocoa project.
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.
27.0 Commercial chocolate
At the chocolate factory the beans are sorted and cleaned, then roasted
and winnowed to remove the outer shells to be sold for animal feed. The
remaining "inner nib" is crushed then heated to melt the cocoa butter and
ground to a thick paste. This paste is called "chocolate liquor" which is
then pressed to extract most of the cocoa butter leaving a cake that is ground
into cocoa powder. Cooking chocolate is made from moulded chocolate liquor.
Dark chocolate is made with chocolate liquor, sugar, cocoa butter, and
vanilla. Milk chocolate is made with chocolate liquor, cocoa butter,
sugar and milk powder. White chocolate is made with cocoa butter but no chocolate
liquor. The beans are roasted and passed through a complex set of milling
processes. The heat of grinding melts the fat and produces chocolate liquor,
which is composed of about 55% fat, 17% carbohydrate, 11% protein, tannins,
ash. Theobromine, the stimulant alkaloid related to caffeine, is found in
amounts ranging from 0.8% to 1.7%. Theobromine may be poisonous to dogs,
so do not give your dog chocolate. Less caffeine is also found. The solidified
liquor forms the bitter cooking or baking chocolate. The fat removed from
the chocolate liquor is cocoa butter that consists mainly of triglycerides
in which the middle fatty acid is oleic acid and the two outside fatty acids
are saturated, generally stearic acid or palmitic acid. The simple composition
of cocoa butter causes a relatively sharp melting point, 30oC
to 35oC. However, the solid is polymorphic, i.e. it can crystallize
in at least three different crystal forms, with melting points varying from
17.3oC to 35oC. Only the fifth of these forms, a so-called
beta-3 type, with a melting point of 33.8oC is suitable because
if the fat crystallizes in an unstable form it will cause problems. For milk
chocolate, the need may be a minimum of 45 g / kg milk fat, 105 g / kg non-fat
milk solids, milk sugars mainly, and 30 g / kg water free, fat free cocoa
paste. Cocoa paste is defined as the product prepared by grinding solidified
chocolate liquor containing not less than 480 g / kg of cocoa butter but
the fat free specification means there is no minimum need for chocolate to
contain cocoa butter. So there is an
incentive to replace the expensive and often variable in quality cocoa
butter with a cheaper fat. White chocolate does have a minimum content of
200 g / kg of cocoa butter specified and also must contain not more than
550 g / kg of sugar, i.e. it can be over half sugar. Fat bloom is the development
of a new phase in a chocolate fat, causing surface disruption with large
clusters to give the grey mould-like coating usually due to poor consumer
storage. Fat bloom in chocolate is distinguished from loss of gloss, which
occurs when small crystals on the surface grow into large crystals and scatter
light. The use of emulsifiers and stabilizers can greatly affect the rate
at which crystal changes occur in the solid state. Various additives, e.g.
sorbitan fatty acid esters, are used to control crystallization and phase
change in substitute chocolate.
Nutritional information on cocoa powder, per 100g ("Cacao Powder" Van Houten
Energy 1390 kJ, Protein 23.5%, Carbohydrates 45 g (sugars 0.5 g), Fat total
21% (saturated fats 13.7%), Fibres 34 g, Sodium 27 mg, Cholesterol 6.3 g,
calcium 130 mg, Iron 22 mg
28.0 Chocolate recipes
28.1.0 Home-made chocolate
Grind 1 to 2 kg of cocoa beans in a manually-operated grinder . Roast
the green cocoa beans over an open fire, while stirring, until they "pop".
However, only 75% should be popped or the beans will burn. Peel the popped
beans as quickly as possible while they are still hot. Grind the beans
with a pestle and mortar and note the bitter taste of the oil produced by
grinding. Chocolate made with the oil gives a richer, yet bitter flavour.
If you want to use the oil, put small piles of the ground paste on aluminium
foil or greaseproof paper on a tray. Leave overnight until the piles harden
to form crude chocolate tablets. If you do not want to use the oil, squeeze
the paste in cheesecloth until most of the oil is squeezed out to form crude
28.2.0 Aztec "Cacahuatl"
Add the crude powder or the chocolate tablets broken down to a fine powder
with a pestle and mortar to cold water in a pan. Add some chilli water,
i.e. chopped chillies soaked in boiling water to make a chilli "tea". Add
vanilla bean pods and honey. Heat the pan while stirring constantly. When
the mixture starts to bubble, quickly remove the pan from the stove and
allow it to cool slightly. Put the pan back on the stove and continue to
stir until boiling. Repeat the cooling and re-boiling to aerate the chocolate
and improve its flavour. The finished Aztec drink should be soft, foamy, reddish, bitter
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 bean. The team of
scientists from the US Department of Agriculture (USDA), will analyse the
more than 400 million parts of the cocoa genome. 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, such as raisins, almonds and macadamia
Before teaching this project, discuss the content of the lessons with
a field officer of the Ministry of Agriculture and get advice on planting
material, planting distances, site for planting, approved mulch, composting,
and control of pests and diseases. Use only the procedures, agricultural
chemicals and insecticides recommended by the local field officer of the
Ministry of Agriculture. If you cannot control insects by hand picking,
ask the Ministry of Agriculture to recommend a chemical spray. All insect
sprays are dangerous. Show the students how to use them safely. Do not
get the spray onto your hands. Do not breathe in the spray. Wash your hands
well after using spray. Keep the spray container in a safe place where
students cannot get it. Spray on a day of no wind but if you must spray
when there is a wind, spray down wind. Make sure the spray does not blow
on other people.
These teaching materials were originally written and illustrated by Mr
J. A. Sutherland, Faculty of Education, University of New England, Armidale,
Australia and later edited by Dr J. Elfick, School of Education, University
of Queensland, Brisbane, Australia.