2 Cocoa Plants Purpose • Students Know the History of the Cocoa Plant

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2 Cocoa Plants Purpose • Students know the history of the cocoa plant. • Students can name botanical characteristics of cocoa plants. • Students can name factors which are important for the growth of cocoa plants and describe diseases and pests of the plant. Overview • Basic historical, botanical and ecological knowledge about the cocoa plant.

Time • 90-135 minutes Material • Printed pictures of the history of the cocoa plant • Cocoa pod • Cocoa tree (or pictures of a cocoa tree) • Handouts for each student

Teachers Support Procedure:

O) Preparation Order (Homework Task) • Give the students this worksheet a week in advance as a preparatory homework assignment. Students interview someone they know and that has cocoa farm about growth factors and diseases of cocoa trees. The results are used in  C) Ecology and cocoa cultivation. ( Through the interview, the students establish a connection between the topic of the teaching unit and the world in which they live. In addition, the interview provides the opportunity to acquire specialist knowledge.)

A) History of cocoa tree • Show a cocoa pod (or a picture of a cocoa tree) and ask the students where the cocoa plant has its origin (e.g. individual students answer / individual students show their guess on a map / the teacher names continents and the students raise their hand at their guess). • Form groups and distribute pictures of the history of the cocoa tree to groups. • Draw a timeline on the blackboard (4000 BC – today). Each group briefly discusses what their picture might represent, what it might have to do with the history of the cocoa tree and what time it alludes to. • One person per group presents the picture and result of discussion and arranges the picture on the timeline on the blackboard. • Correct the sequence of the pictures on the blackboard, explain what the pictures show and note the most important information on the blackboard. The students write down the noted information.

B) Botanical characteristics • Ideally, go out with the class to a cocoa tree near the school grounds and inspect it closely. If this is not possible, pictures of a cocoa tree can be shown in the classroom. • With the help of the cocoa tree or the image, students draw a sketch of a cocoa tree and label its parts. • The botanical characteristics of the cocoa tree should be written down (if possible, these can be worked out independently on the basis of an examination of a tree and/or an Internet research and then corrected together. If this is not possible, the characteristics can be worked out together in class).

C) Ecology and cocoa cultivation • Task 1: Collect and discuss the student results of the preparatory homework. Make additions if necessary. • Each of the subsequent tasks (2-5) should first be solved individually or in groups of two. Then the results should be corrected in class. The purpose of the tasks is briefly described below: Task 2: By reading a text the students elaborate and summarize the growth conditions of cocoa trees. Task 3: With the help of the world map and the indication of the largest cocoa-growing countries, the students work out the location and climate zone of the regions that cultivate cocoa. Task 4: On the basis of climate data from individual regions and the results of Task 2, the students assess where cocoa can be grown and where not. Task 5: The students learn that cocoa can be grown in different cultivation systems. This information is important because these two cultivation systems appear again and again in the course of the teaching unit. The results of the task should be discussed in class. Note: The purpose of this task is to collect some first ideas of the students, so the answers do not have to be correct.

Wrap-up Give the students the following task: “Imagine you are coming home, and your mother or father asks you what new things you have learned today. What will you tell them?”  Let the students first think individually and take notes. Then let them exchange with the person sitting next to them. At the end, some students present their results to the class.

Technical hints:

A) History of cocoa tree

Pictures and descriptions Further information

3300 BC: First traces of the cocoa tree in Santa 3300 BC: Origin Ana (La Florida), Ecuador, South America. Where exactly the origin of the cocoa tree lies has not yet been completely clarified. Traces of clay vessels found in Santa Ana (La Florida) in the upper part of the Amazon basin in the southeast of Ecuador show that the cocoa tree has been cultivated there since at least 3300

BC. It probably originated there and later spread over Central America. (Source: https://www.theobroma-cacao.de)

1500 BC: Cultivation of cocoa trees in Central 1500 BC: Olmecs America by Olmecs. The word "cacao," The Olmecs were the first known high culture in originally pronounced "kakawa," comes from present-day Mexico (1500 to 400 BC). This the Olmec language. culture is especially known for its colossal stone heads, which probably represent rulers. Around 1500 BC. the Olmec started to cultivate cocoa trees in Central America. (Source: https://www.theobroma-cacao.de, OroVerde)

Source: https://www.slideshare.net/olmecdragons/the- olmec-culture

300-900 AC: Mayans develop an irrigation 300-900 AC: Mayas system to produce the highest possible cocoa The Mayans settled in southern Mexico a few yields. Use of cocoa as a kind of holy water, as a centuries after the fall of the Olmecs. They medicinal plant, as a sacrifice, and as a means cultivated the cocoa tree on large fields and of payment. developed irrigation systems to achieve the highest possible yields. Through the trade routes, cocoa beans could be transported from the few suitable cultivation areas to the entire Mayan empire. The Mayas produced a cocoa drink from the cocoa beans. This was used as a kind of holy Picture: Mayan mural water to celebrate the transition of the (Source: National Museum of Anthropology, Mexico City) adolescent into adulthood. Cocoa was used as a sacrifice for the gods and as a medical plant: it was a universal medicine for diarrhoea, measles and birth pains. Furthermore, the cocoa bean was used as a means of payment. (Source: https://www.theobroma-cacao.de, OroVerde)

1300-1500: The Aztecs used cocoa like the 1300-1500: Aztecs Mayans did. They also adopted the sacred drink At the beginning of the 13th century the high from the Mayans and called it "Xocolatl" (xoco = culture of the Aztecs began. To the Aztecs bitter; atl = water). cocoa was a sacred tree, the seeds of which had been brought from paradise by the prophet Quetzalcoatl. They adopted the tradition of the sacred drink from the Mayans, and called it "Xocolatl" (xoco = bitter; atl = water). The Picture: Aztecs preparing the special spicy cocoa Aztecs used cocoa and cocoa butter as a drink (Source: medicine, as a gift, as a sacrifice and as a means https://onthecocoatrail.com/2012/11/30/the-first-cocoa- of payment. For example, a turkey cost 200 recipes/) cocoa beans and an avocado between one and three cocoa beans. (Source: https://www.theobroma-cacao)

1600: Cocoa beans and the drink “Xocolatl” 1600: Expansion arrived in Europe. The first European to get to know cocoa was Christopher Columbus in 1502. In the 16th century the cocoa beans and the necessary equipment for the preparation of the "Xocolatl" arrived in Europe. In the beginning, chocolate was a luxury good for the rich. But the demand of the Europeans for the chocolate drink increased enormously, therefore the cultivation areas were also expanded. Large cocoa plantations were established in Central Picture: Chocolate drink for the aristocrats America, South America and the West Indies. (Source: www.wikipedia.com) (Source: https://www.theobroma-cacao.de)

1753: Carl von Linné gives the scientific name 1753: Scientific Name Theobroma cacao. Theobroma means 'food of The scientific name Theobroma cacao was given the gods' in Latin. Cocoa originates from the to the species by the botanist Carl von Linné in Aztec term cacahuatl (cacao beans). 1753, when he published it in his famous book Species Plantarum. Theobroma means 'food of the gods' in Latin. The word cocoa originates from the Aztec term cacahuatl (cacao beans). (Source: https://www.theobroma-cacao.de)

About Carl von Linné: He was a Swedish naturalist who laid the foundations of modern botanical and zoological taxonomy with his binary nomenclature (=two-term naming system).

Picture: Carl von Linné, 1707 – 1778

1878: Cocoa plants were End of 1800: Arrival in West Africa brought to continental Towards the end of the 19th century the first Africa (Ghana) cocoa plants arrived on continental Africa. In 1879 a local planter brought back a pod from the island of Bioko and sowed the first beans in Ghana. He thus grew a few trees, the origin of

the entire African stock, which has been characterized ever since by its considerable 4

homogeneity. By 1911 Ghana had become the world's most important producer of raw cocoa. Cocoa was introduced into Nigeria from Ghana around 1890. The first plantations in Côte d'lvoire, established in the eastern regions in 1905, were not a success and it was only from 1912 onwards, following a government extension programme, that this new crop was grown on a wider scale. Towards the end of the 19th century, the Germans introduced cocoa into Cameroon. Today: Main cocoa producing countries are: Today: Côte d’Ivoire, Ghana, Indonesia, Ecuador, Main Cocoa-Producing Countries 2017/18 Cameroon.

Picture: Main cocoa-producing countries in the world. (Source: International Cocoa Organization)

B) Botanical characteristics

Further information for the teacher: The genus Theobroma includes about twenty species of which only Theobroma cacao L. is of economic interest. The cultivated cocoa tree is divided into three basic types or varieties: • Forastero (also known as Amelonado) is a robust variety that delivers high yields, but with a medium quality. This variety accounts for 90% of global cocoa cultivation. It is primarily cultivated in West Africa. • Corillo provides high quality cocoa, but is susceptible to diseases and pests. Only 5% of the world’s production is Criollo. This variety is mainly cultivated in South America. • Trinitario is a cross between Criollo and Forastero. The Trinitario combines the robustness of the Forastero with the aroma of the Criollo. It is usually self-sterile, which is why it can only be propagated by cutting or grafting. Like the Criollo, the Trinitario's share of world production is rather small. This variety is cultivated in South and Central America, as well as in many African and Southeast Asian Countries.

Development of cocoa tree (visualization on page 12)1: The development of the cocoa tree can be divided into three phases: 1) Soldier phase: Cotyledons (=seed leaf) are raised a few centimetres above the ground.

1 Arntzen & Ritter (1994). Encyclopaedia of Agricultural Science, Vol. 1

2) Vertical growth phase: the primary stem grows because of the activity of a terminal bud until the plants are 1-2m high. 3) Jorquette formation: About five buds at the terminal end of the vertical stem grow out sideways simultaneously, to produce plagiotropic (growing at an oblique or almost horizontal angle) shoots. These shoots, also called fan branches, grow indefinitely.

If the terminal bud is damaged prior to jorquetting, the buds in the top part of the stem produce vertical “choupon” shoots. Choupons, like all vertical branches, have a spiral arrangement of leaves in contrast to fan branches which have an alternate arrangement. Each choupon is determinate in growth and capable of eventually forming a jourquette. Choupons may arise from the base of the trunk also. The tree canopy becomes higher by vertical elongation of the choupons just below the jorquette fork, and produces a second story of jorquettes. The new jorquette thus takes over the canopy, whereas the previous jorquette dies off. The process may be repeated several times resulting in a still higher tree canopy.

C) Ecology and cocoa cultivation2

The solution sheet lists the most important characteristics of cocoa cultivation and ecology. Further information can be found at https://www.icco.org/about-cocoa/growing-cocoa.html.

Background Information on Task 5: Cocoa Monoculture (no shade-trees) vs. Agroforestry (with shade-trees) Both young and mature cocoa trees require some degree of shading to produce high yields. The amount of light a young tree receives influences its growth habit. For young trees, shade helps to produce a tree structure suitable for cropping later on, with long internodes but short branches. Little shading results in bushy trees because of short internodes and long side branches. Neither growth habit is actually preferred in a mature tree. Too much light delays canopy formation in young trees, thus delaying flowering. Another advantage of shade is protection from wind, since young cocoa leaves are susceptible to mechanical damage by injury at the pulvinus (the swollen region at the base of the leaves) even by low speed winds. The shade-trees protect the humus layer of the soil from drying out. Moreover, if leguminous trees are selected, they keep up the available nitrogen through the nitrogen-fixing capacity of their root nodules. An additional benefit conferred by shade-trees is that their leaves, twigs, and flowers constitute litter for the replenishment of organic matter of the soil.

2 Arntzen & Ritter (1994). Encyclopaedia of Agricultural Science, Vol. 1

2) Cocoa Plants O) Preparatory Homework

Task: Ask someone who owns / manages a cocoa farm the following two questions:

A) What does the cocoa tree need to grow well?

Notes:

B) What are the pests and diseases of the cocoa tree?

Notes:

2) Cocoa Plants O) Preparatory Homework - Possible additions by the teacher

Task: Ask someone who owns / manages a cocoa farm the following two questions:

A) What does the cocoa tree need to grow well?

Notes:

- Light - Water / Rain - Soil - CO2 - Nutrients

Management: - Pruning - Cutting chupons - Weeding - Pest and disease management (i.e. collection of diseased pods and burning, pesticides,…) - Removal of mistletoes and moss - Nutrient management (i.e. organic practices, synthetic fertilizer) - Shade management

B) What are the pests and diseases of the cocoa tree?

Notes:

Mirids are the major insects that affect cocoa worldwide. The most common species in West African countries are Distantiella theobroma and Sahlbergella singularis. These insects use their needle-like mouthpart to pierce the surface of cocoa stems, branches and pods and suck the sap of the cocoa tree. While sucking, they inject toxic spit into the plant. This causes the dying of internal cocoa tissues. Infestation on cocoa pods results in minor direct losses, if any. Beans from these pods are generally not affected but may be a little smaller than without infestation. However, the many little scars on the pods are an easy target for black pod, which often causes more losses than the mirids itself.

Swollen Shoot Virus This virus, transmitted by aphids, is noticeable by swelling of twigs and petioles and a reddish pattern on the leaf surface. The virus can only be fought by removing the infected trees. In the first year the virus leads to a harvest loss of 25%, in the second year to a complete loss of harvest, and the cocoa tree finally dies.

Black Pod Black Pod is the most important fungal disease of cocoa worldwide. The stem, leaves, flowers and above all the fruit are attacked. The first symptom of a fruit is a brown spot, which becomes visible about five days after infection, rapidly enlarges and becomes black. The spores of the fungus are spread by raindrops, insects and wind. They germinate at high humidity and relatively low temperatures.

For more Information about diseases see: https://www.icco.org/about-cocoa/pest-a-diseases.html

2) Cocoa Plants A) History of cocoa tree

2) Cocoa Plants Solution A) History of cocoa tree

3300 BC: First traces of the cocoa tree in Santa Ana (La Florida), Ecuador, South America.

1500 BC: Cultivation of cocoa tree in Central America by Olmecs. The word "cacao", originally pronounced "kakawa", comes 300-900 AC: Mayans develop from the Olmec language. irrigation system to develop highest possible cocoa yields. Use of cocoa as a kind of holy water, as a medicinal plant, as a sacrifice and as a means of payment.

1300-1500: The Aztecs used cocoa like the Mayans did. They also adopted the sacred drink from the Mayans and called it "Xocolatl" (xoco = bitter; atl = water). 1600: Cocoa beans and the drink “Xocolatl” were brought to Europe. 1753: Carl Linnaeus gives the scientific name Theobroma cacao. Theobroma means 'food of the gods' in Latin. Cocoa originates from the Aztec terms cacahuatl 1878: Cocoa plants were brought (cacao beans). to continental Africa (Ghana).

Today: Main cacao producing countries are: Côte d’Ivoire, Ghana, Indonesia, Ecuador and Cameroon.

2) Cocoa Plants B) Botanical Characteristics

Task: a) Draw a sketch of a cocoa tree. b) Name the parts of the plant. c) Fill out the profile below.

Jorquette = The point at which the vertical stem forks to produce horizontal shoots Choupon = Vertically growing shoots

Name: ______Scientific Name: ______

Family: ______

Height: ______

Roots: ______

Leaf: ______

Flowers: ______

Fruit: ______

Pollination: ______

2) Cocoa Plants Solution B) Botanical Characteristics

2nd Jorquette Jorquette = The point at which the vertical stem forks to Shoots produce horizontal shoots

Choupon = Vertically growing shoots

Leaves First Jorquette Pods or fan branches

Flowers

Trunk Basal chupon

Surface lateral roots

Taproot

Name: Cocoa tree Scientific Name: Theobroma cacao L. Family: Malvaceae Height: Up to 15 m, but are pruned to 4 m (easier for harvest)

Roots: Tap-root (reach a depth of 1-1.5m) / lateral roots (in the top 50 cm of soil) Leaf: Lanceolate, elongated; 20-30 cm long, 7-12 cm wide Flowers: In clusters directly on stem and older branches (= cauliflory) / 7 to 10 cm long, five sepals, five white or light red petals / Blossom: Flowers form throughout the year Fruit: Cocoa pod (20 to 30 fruits per tree and year, in good years up to 50 fruits) - Shape: elongated to spherical, up to 30 cm long / Weight: up to 500 grams - Colour: green-yellow to red (depending on the variety) - Seeds: up to 50 seeds (commonly called “beans”) embedded in a white pulp Pollination: By tiny flies (Forcipomyia sp., i.e. midges). Thousands of flowers per tree, but only 0.5 to 5 % of the flowers are pollinated successfully.

2) Cocoa Plants C) Ecology and cocoa cultivation

Task 1: Discuss the findings of the preparatory homework in class and complete your notes on the homework sheet O) Preparatory homework.

Task 2: Read the following text and summarize the growth conditions of the cocoa tree in the relevant boxes.

Cocoa grows best in a warm and humid environment. The temperature in cocoa-growing areas usually ranges from a maximum of 30°-32°C to a minimum of 18°-21°C, the ideal mean temperature being 26°C. Rainfall should be plentiful and well distributed throughout the year. An annual rainfall level of between 1,500mm and 2,000mm is generally preferred. Trees are very sensitive to a soil water deficiency. Dry spells, where rainfall is less than 100mm per month, should not exceed 3-4 months. The cocoa tree will make optimum use of any light available and traditionally has been grown under shade. Its natural environment is the Amazonian forest which provides natural shade-trees. Shading is indispensable in a cocoa tree's early years – it protects the young trees from wind and helps to produce a tree structure suitable for cropping lager on. Cocoa needs a soil containing coarse particles and with a reasonable quantity of nutrients, to a depth of 1.5m to allow the development of a good root system. Below that level it is desirable to have permeable material, so that excess water can drain away. Cocoa will withstand waterlogging for short periods, but excess water should not linger. The cocoa tree is sensitive to a lack of water, so the soil must have both water retention properties and good drainage. Soil types best suited for cocoa are clay-loams, loams, and sandy loams in the pH range of 5.0-7.5. The soil should also have a high content of organic matter: 3.5% in the top 15 centimetres of soil.3

Temperature Soil

Rain Light

3 https://www.icco.org/about-cocoa/growing-cocoa.html 13

Task 3: The world's largest producers of cocoa are: Ivory Coast, Ghana, Indonesia, Nigeria, Cameroon, Brazil, Ecuador, Mexico, Peru, Dominican Republic, Togo, Papua New Guinea, Colombia. a) Colour these countries on the world map. Look at the latitudes. What do you notice?

Zurich

Kumasi Quito

Darwin

b) In which climate zone are the marked countries?

Task 4: Compare the growing conditions of the cocoa tree (see Task 2) with the climate data of Kumasi, Zurich, Quito and Darwin (see table). Where can cocoa be grown and where not? Justify your decision.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Kumasi Mean T (°C) 26.5 27.6 27.9 27.4 27.3 25.8 24.7 24.4 25.4 26 26.8 25.7 (GHA) Rain (mm) 8 63 136 150 176 216 133 79 169 190 86 32 Zurich Mean T (°C) 0.2 1.7 5.1 8.7 12.9 16.3 18.4 17.6 14.9 10.2 4.7 1.3 (CH) Rain (mm) 5 68 68 89 105 129 119 132 90 68 80 72 Quito Mean T (°C) 14 14 14 13.9 14.1 13.6 13.7 13.8 13.9 14 13.8 14 (ECU) Rain (mm) 120 137 163 189 116 56 22 32 84 130 120 104 Darwin Mean T (°C) 28.2 27.9 28.1 28.1 26.7 24.8 24.4 25.6 27.7 29.1 29.2 28.8 (AUS) Rain (mm) 426 359 335 86 15 2 1 4 18 76 121 251

Task 5: Check out the two main cultivation methods of cocoa.

Pictures: OroVerde

Monoculture Agroforestry

Only cocoa trees are planted using this An agroforestry system is a cultivation method. The trees are very multifunctional system where cocoa is narrow (up to 1,600 trees per hectare at a deliberately grown on the same plot as distance of 2.5m x 2.5m). other trees and/or crops.

a) What is the more common form of cultivation in your area?

b) Do you think the cultivation method of a) is better or worse than the other method? Justify your answer.

2) Cocoa Plants Solution C) Ecology and cocoa cultivation

Task 1: Discuss the findings of the preparatory homework in class and complete your notes on the homework sheet O) Preparatory homework.

Task 2: Read the following text and summarize the growth conditions of the cocoa tree in the relevant boxes.

Cocoa grows best in a warm and humid environment. The temperature in cocoa-growing areas usually ranges from a maximum of 30°-32°C to a minimum of 18°-21°C, the ideal mean temperature being 26°C. Rainfall should be plentiful and well distributed throughout the year. An annual rainfall level of between 1,500mm and 2,000mm is generally preferred. Trees are very sensitive to a soil water deficiency. Dry spells, where rainfall is less than 100mm per month, should not exceed 3-4 months. The cocoa tree will make optimum use of any light available and traditionally has been grown under shade. Its natural environment is the Amazonian forest which provides natural shade-trees. Shading is indispensable in a cocoa tree's early years – it protects the young trees from wind and helps to produce a tree structure suitable for cropping lager on.. Cocoa needs a soil containing coarse particles and with a reasonable quantity of nutrients, to a depth of 1.5m to allow the development of a good root system. Below that level it is desirable to have permeable material, so that excess water can drain away. Cocoa will withstand waterlogging for short periods, but excess water should not linger. The cocoa tree is sensitive to a lack of water, so the soil must have both water retention properties and good drainage. Soil types best suited for cocoa are clay-loams, loams, and sandy loams in the pH range of 5.0-7.5. The soil should also have a high content of organic matter: 3.5% in the top 15 centimetres of soil.4

Temperature Soil

Optimum annual mean T: 26°C Soil depth of >1.5m Minimum: 18°-21°C Clay-loams, loams, and sandy loams Maximum: 30°-32°C Water retention properties and good drainage needed

pH between 5.0-7.5 High content of organic matter needed

Rain Light

Optimum: between The cocoa tree will make 1,500mm and 2,000mm optimum use of any light annually available

Dry spells with Shading is indispensable in a <100mm/month should not cocoa tree's early years exceed 3-4 months

4 https://www.icco.org/about-cocoa/growing-cocoa.html 16

Zurich

Quito Kumasi

Darwin

b) In which climate zone are the marked countries?

They are in the tropical zone  Cocoa only grows there.

Kumasi: Possible: annual average temperature is good (26.3 °C) and there is just enough rainfall (1438mm) Zurich: Not possible. Annual average temperature is too low (9.3 °C) and there’s too little rainfall (1025mm). Quito: Not possible. Annual average temperature is too low (13.9 °C) and there’s too little rainfall (1273mm). Darwin: Not possible. Annual average temperature (27.4°C) and total amount of rainfall (1694mm) are good, but there are too many months in a row with rainfall <100 mm.

Task 5: Check out the two main cultivation methods of cocoa.

Monoculture Agroforestry

Only cocoa trees are planted using this An agroforestry system is a multifunctional cultivation method. The trees are very system where cocoa is deliberately grown on narrow (up to 1,600 trees per hectare at a the same plot as other trees and/or crops. distance of 2.5m x 2.5m).

a) What is the more common form of cultivation in your area?

Individual results

b) Do you think the cultivation method of a) is better or worse than the other method? Justify your answer.

Individual results

2) Cocoa Plants Pictures to print A) History of cocoa tree