Common Baobab Tree Diseases: How to Identify and Treat Them

Baobab leaves (Adansonia digitata) in coast Kenya Ⓒ P. Maundu, 2019

Baobab tree in Burkina faso Ⓒ P. Maundu, 2022

A woman picking Baobab leaves in Kenya Ⓒ P. Maundu, 2022

A woman sorting Baobab leaves Ⓒ P. Maundu, 2014

Baobab (Adansonia digitata) fruits Ⓒ P. Maundu, 2007

Baobab and Cassava leaves Ⓒ P. Maundu

Baobab fruit pulp Ⓒ P. Maundu, 2022

Baobab fruiting branch Ⓒ P. Maundu, 2022

Baobab leafy vegetables Ⓒ P. Maundu, 2022

Baobab leaves as vegetables in Inyuu Ⓒ J. Kioko

Baobab tree in Burkina faso Ⓒ P. Maundu, 2014

Chopped Baobab leaves in Inyuu Ⓒ J. Kioko

Cluster of leafless baobab trees Ⓒ J. Muia

Cooked Baobab leaves in coast Kenya Ⓒ P. Maundu, 2021

Mixture of Baobab and Cassava leaves Ⓒ J. Muia, 2021

Variation of Baobab fruits Ⓒ P. Maundu, 2021

Woman harvesting tender Baobab leaves in Burkina faso © P. Maundu, 2014

Young Baobab leaves vegetables in coast Kenya Ⓒ J. Kioko, 2022

Variation in baobab fruits shapes Ⓒ P. Maundu, 2021

Baobab tree nursery in Kilifi, J. Muia, 2023 Ⓒ J. Muia, 2023 Scientific Name

Geographical Distribution in Africa

Baobab is indigenous in most tropical African countries. Baobab has been introduced in many other countries in the tropics and sub-tropics of the world. Other Local names Read more

Angola: Mbondo, Mukua (Kimbundu), Imbondeiro (Portuguese) (Bossard, 1996); Kibaba (Kikongo) (Göhre et al., 2016).

Benin: Sonnan (Bariba), Kadara (Kotokoli), Fonla (Boko), Butuobu,Tituokari (Gourmantché), Gatongaboi (Anii), Kôô (Dendi), Kutunga (Zerman), Kpèborè (Waama), Mutorumu, Titookanti, Yètookpèrè (Otammari), Zinzoun (Cotafon), Kpassa (Fon, Mahi, Aïzo), Otché (Tchabè, Idatcha, Ifè, Holly (Achigan et al., 2010); Donwo (Bariba); Boboli (Peuhl), Kpassagoto (Fon) (Adjanohoun et at.,1989).

Burkina Faso: Poo-Qô (Bissa) (Sita, 1978); Kôon (Sanan) Zerbo et al., 2011); Tohega (Moore) (Belem et al.,2007); Trega, Twega, Toayga (More), Ngigne (Senufo) (Sidibe & Williams., 2002).

Cameroon: Boko; Boki (Foufouldé) (Ngene, 2015)

Chad: Hamar, Hamaraya (Sidibe & Williams, 2002)

Cote dIvoire: Fromdo (Baule), Ngigne (Senufo) (Sidibe & Williams, 2002), Sirra (Dioula) (Ambé, 2001); Bu ba (Dioula), Boki (Malinké), Frondo (Baoulé), Ngigué (Sénoufo), Zizon (Fon), Toéga (Mossi), Baobab (French) (Aké-Assi, 1992).

DRC: Nkondo (Kongo); Pain de singe (French) (Latham and Mbuta., 2006)

Egypt: Habhab (Sidibe & Williams., 2002)

Eritrea: Tebeldi (Arabic), Asa (Kunama), Himeret (Tigre), Dim (Bilen), Dira (Bilen), Dari (Nara), Duma (Tigrigna) (Bein et al., 1996)

Ethiopia: Bamba (Amargna), Ba’obaab, Humaar (Oromugna), Yag (Somalgna), Dima (Guragigna), Hermer banba, Kommer, Momret (Tigrigna) (Tesemma et al., 2007); Hemmer, Dumma (Tigre), Bamba (Amhara) (Sidibe & Williams, 2002).

Ghana: Tùá (Dagomba) (Blench & Dendo, 2006); Odadie (Twi, in the South), Tua (Nankani, In the North) (National Academies of Sciences, 2006).

Guinea Bissau: Sito, Sira (Mandinka) (Orwa et al., 2009); Láté, Átè (Balanta), Buàs (Biafada), Uáto, Uvato (Bijagó), Cabaceira, Cabacera, Calabacera, (Guinean Creole), Baobab, Pain De Singe (Fruit) (French), Bóè (Fula), Bedom-Hal, Burungule-Burúnque (Mancanha), Citô (Mandinga), Bebáque, Bedom-Hal, Brungal (Manjaco), Mbéke (Nalu), Burungule (Pepel), Cabaceira, Calabaceira, Imbondeiro (Portugese), Kiri (Sosso) (Catarino et al., 2016).

Guinea: Séda, Sira (Malinké), Boki (Poular, Malinke), Kiri (Soussou), Bohe (Foula du Fouta-Djallon) (Carrière, 1994).

Kenya: Muyu (Bajun), Jah (Boni), Muyu (Chonyi), Muuyu (Digo), Musemba (Embu), Muuyu, Mauyu {Fruit}(Giriama), Muamba, Mwaamba, Namba {Fruit}(Kamba), Olmesera (Masai), Mubuyu (Malakote), Muramba (Mbeere), Muiramba, Muramba (Meru), Yak (Orma), Lamai (Samburu), Yak (Sanya), Yak, Yaaq (Somali), Mbuyu, Muuyu (Swahili), Mlamba (Taita), Muguna Kiriindi (meaning-that which helps the masses), Muramba (Tharaka) (Maundu & Tengnas, 2005)

Madagascar: Reniala (Malagasy), Bozo (Sakalava dialect) (National Academies of Sciences, 2006); Baobaba, Baovola, Bozobe, Boy, Boringy, Mboio, Mboy, Rainiala, Reniala, Ringy, Sefo, Vanoa, Vontana (Malagasy) (Porcher Michel et al. 1995). Note: Some of the names may refer to other species of baobab.

Malawi: Bu ba (Dioula), Boki (Malinké), Frondo (Baoulé), Ngigué (Sénoufo), Zizon (Fon), Toéga (Mossi) (Aké-Assi, 1992); Mlonje (Yao), Mnambe, Mlambe (Chichewa), Mbuye (Nkonde) (Sidibe & Williams, 2002).

Mali: Sira, Nsira (Bambara), Zige (Minyanka), Zenge (Senoufo), Iya, Ile (Bwa), Pii (Bobo-Fing), Oro (Dogon) (Malgras, D., 1992); Idal (Sidiyenne, E. A., 1996); Oro (Dogon) Konian, Ko (Sonrai), Konian (Dierma), Babbe, boki, Olohi (Peulh), Sira, Sito (Madinke), Ngigne (Senufo) (Sidibe, M., & Williams, J. T., 2002).

Mauritania: Teidoum (Arabic), Gokki (Pulaar) (Tall, 1994).

Mauritius: Ros Mapon, (Creole), Anai Pouliya, Koye (Tamoul) (Daruty, 2018).

Mozambique: Mulambe, Malambe, Ximuwa, Ximuhu, Ximuvo (Changana) (Ribeiro, A., 2010)

Namibia: Mubuyu (Lozi) (Chinsembu & Hedimbi 2010).

Niger: Kuka (Hausa), Koo Mya (Zarma), Bokki (Peuhl), Taedrumpt (Tamacheck), Bulu Kuwa (Beriberi) (Adjanohoun, 1988).

Nigeria: Igi ose (Yoruba), Boki, Bokchi (Fula) (Orwa et al., 2009); Ose (Yoruba), Igi-Ose, Kuka (Hausa) (Ainslie, 1937); Kulambali, Gorakh-imli (Green institute, 2018); Kuka, Kouka (Hausa), Boki, Bokki (Fulani) (Sidibe & Williams, 2002).

Rwanda: Igiti cya bawoba (Kinyarwanda)

Senegal: Baak (Seereer), Bokki (Pulaar), Kommer, Hermer Banba, Momret, Duma (Tigrigna), Bui, Buee, Goui, Gui, Gwi (Wolof) (Orwa et al., 2009); Boki (Peul, Tocolor), Boi (Fouladou), Gui (Pour Larbre), Lalo (Pour La Feuille) (Wolof), Sira, Sito (Bambara), Boy, Boiö, Boki (Peuhl) (Pordié & Magaud, M, 2001); Bubak (Diola) (Le Grand, & Wondergem., 1987); Ibak, Bak (Niominka), Sito (Socé) (Kerharo & Adam, 1964); Boubakakou (Dirla fogny), Boui (Wolof) (Sidibe & Williams, 2002).

Somalia: Yak (Somali) (Orwa et al., 2009)

South Africa: Mowana (Tswana), IsiMuku, Isimuhu, UmShimulu (Zulu) (Orwa et al., 2009); Ximuwu (Tsonga), Muvhuyu (Venda) (Andrew Hankey., 2004); Motsoo (Pedi) (Mongalo, & Makhafola., 2018); Shimuwu (Tsonga), Muvuhuyu (Tswana), Mayuy, Muuyu, Tsongoro (Seeds) (Shona) (National Academies of Sciences, 2006); Kremetart, Kremetartboom, Mubuyu, Muyu, Mbuyu, Mkulukumba, Mlambe (Afrikaans) (Sidibe & Williams, 2002); Umkomo (Ndebele) (National Academies of Sciences, 2006)

Sudan: Tabaldi (Gongoleis) (El-Kamali, 2009); Humeira (National Academies of Sciences., 2006); Dungwol (Dinka); Gunguleiz, Tebeldi, Humr, Homeira, Dungwol (Sidibe & Williams, 2002)

Tanzania: Mesera (Arusha), Mpela (Gogo), Dakaumo (Goro), Mkondo (Hehe), Gendaryandi (Iraqw), Mpela (Lugu), Olmesera (Masai), Muwiye (Mbug), Mramba (Pare), Mwiwi (Rangi), Gele (Sand), Mkondo (Sangu), Mwanda, Mwandu, Ngwandu (Suku), Mbuyu (Swah) (Mbuya et al, 1994); Nonji (Kingindo) (Haerdi, F., 1964); Moandu (Sukuma) (Kokwaro, 1993).

Togo: Todi (Nawdem), Tokala, Tuéleg, Kankanssio (Moba) (Adjanohoun, E et al., 1986)

Zambia: Mubuyu (Bemba), Mubuyu, Muyu (Lozi), Mbuyu, Mkulukumba, Mlambe (Nyanja) (Orwa et al., 2009)

Zimbabwe: Mbuyu, Muuyu (Shona), Umkhomo (Ndebele) (Hyde, M.A.,2021)

Adansonia digitata, commonly known as the African Baobab, is a highly adaptable and drought-resistant fruit tree found in the arid and semi-arid regions of Sub-Saharan Africa. It is the sole species of the Adansonia genus in tropical Africa, distinguishing it from the other eight species found in Australia, Madagascar, and various islands in the South Pacific and Indian Ocean. Despite being a softwood tree, the African Baobab stands out as one of the longest-living trees, with a lifespan of up to 3,000 years. It possesses exceptional traits that enable it to thrive in dry climates, including an extensive root system, high water retention capacity, and early leaf shedding. Its smooth bark provides excellent resistance to drought and fires.

Within African communities, the Baobab tree and its products hold varying significance for sustenance and income generation. The baobab leaves, which are highly nutritious and rich in essential nutrients such as calcium, potassium, and vitamin C, are a popular vegetable in local communities throughout Africa. In the savannahs south of the Sahara, baobab leaves are widely consumed, making them one of the most common food sources between Senegal and Lake Chad. It is worth noting that although baobab trees are found in Eastern and Southern Africa, the leaves are rarely consumed in these regions.

Baobab leaves are harvested fresh and cooked as a potherb in some areas, while in others, they are dried and crushed for later use. These leaves have a unique taste that is slightly sour, tangy, and sweet, with hints of nuttiness or earthiness. When cooked, their flavour becomes mild and reminiscent of spinach. They have a slightly tough and fibrous texture, and the mucilage released during cooking gives them a slightly slippery and slimy consistency. Baobab leaves are commonly added to soups, stews, sauces, and relishes, enhancing the flavour and nutritional value of the dishes while also thickening them. They are frequently served as a side dish, similar to spinach, and poured over various staple foods such as yam, cassava, maize, millet, sorghum, etc., to complete the main meal.

Baobab leaves have also been found to possess various medicinal properties. In traditional African communities, powdered baobab leaves are commonly used by traditional healers to treat ailments such as asthma, fever, malaria, smallpox, and diarrhoea. Studies have demonstrated their potential as anti-inflammatory, antipyretic, anti-diarrheal, and antiplasmodial agents. Furthermore, these leaves exhibit remarkable antioxidant properties, further adding to their therapeutic potential. Further research is necessary to determine the safety and effectiveness of using baobab leaves for medicinal purposes in humans.

During the rainy season, baobab leaves serve as a vital source of sustenance for domestic livestock and wild animals, including elephants and impalas, especially when grazing lands are depleted and new growth has yet to emerge.Furthermore, the baobab leaves are a significant source of food for animals, and the tree itself provides habitats for many wild animals, contributing to the preservation of biodiversity in the region. Additionally, the tree provides other ecosystem services such as carbon sequestration, soil enrichment, air and water quality improvement, and biodiversity conservation (Hankey, 2004).

(National Academies of Sciences, 2006, Hankey, 2004, Alao et al., 2016, Maundu & Tengnas, 2005).

Adansonia digitata is a succulent, deciduous tree that can grow up to around 20 meters tall, often with a very sparse crown, especially in the drier parts of its range. The swollen, urn-shaped bole eventually becomes very wide, often exceeding the diameter of the crown, and can be up to 10 meters across. The stem is covered with a bark layer, which may be 50-100 mm thick (Fern, 2021). Bark; is greyish brown and usually smooth but can often be variously folded and seamed from years of growth. Leaves; are hand-sized and divided into 5-7 finger-like leaflets. Flowers; The flowers are large, white, or yellow, with prominent stamen protruding over crinkled petals and sweetly scented. They emerge in the late afternoon from large round buds on long drooping stalks in early summer. Large, egg-shaped Baobab fruits develop at the early stages of growth. Fruits; are green in color, turning brownish-grey as the fruit ripens. Unlike the flowers, the fruits hang pendulously off the branches on long pedicels (Hankey, 2004).

Baobab leaves as vegetables in Inyuu © J. Kioko

Baobab fruiting branch © P. Maundu, 2022

Baobab tree nursery © J. Kioko

The mature fruit consists of a hard, woody outer shell covered with yellowish-brown hairs that feel velvety. They exhibit different forms; small and big, tapered and rounded, and even the fruit skin hair hue. The fruit contains red-brown and coarse fiber that crisscross the fruits and holds creamy powdery fruit pulp. The fine pulp covers large kidney-shaped seeds. Roots; Baobab tree produces an extensive network of lateral roots that end in tubers. The seedlings produce prominent taproot, which is quickly replaced by laterals. Roots of mature trees rarely extend beyond 2 meters and are relatively shallow, which is one reason why old trees frequently fall over.

Variation in Baobab fruits Ⓒ P. Maundu, 2021

Baobab fruit pulp Ⓒ Maundu, 2022

Annual rainfall: Baobabs are most common, where mean annual rainfall is 200-1,200 mm. However, they are also found in locations with as little as 90 mm or as much as 2,000 mm of mean annual rainfall.

Altitude: The Baobab is usually found in elevations ranging from 0-1,300 m above sea level.

Soil type: The tree grows on a wide range of soils; however, A digitata shows a preference for acidic, well-drained soils (pH <6.5), preferably with sandy topsoils overlaying loamy substrates (Orwa et al., 2009).

Temperature: Baobab thrives where the mean annual temperature is 20-30°C. It succumbs to frost. Reportedly, germination is achieved only when soil temperature exceeds 28°C (National Research Council, 2006).

Cluster of leafless Baobab trees in Coast Kenya Ⓒ J. Muia, 2022

The Baobab trees natural regeneration process is impeded by multiple factors, including browsing animals, prolonged drought, and uncontrolled bushfires. Furthermore, the seeds exhibit low germination rates, with the process naturally taking several years to initiate, often requiring fire to break dormancy. In addition to this, the digestive tract of mammals such as elephants and baboons can facilitate seed dormancy breakage, thereby contributing to the Baobabs natural propagation (Maundu & Tengnas, 2005).

The propagation of African baobabs is predominantly achieved through seed germination, which requires specific conditions to be effective. Mechanical scarification is a crucial step for successful germination, as the seeds have a hard and thick seed coat that hinders water absorption, resulting in a prolonged emergence period of up to several year.

According to Maundu and Bo Tengnas (2005), seed germination of Baobab trees can be induced by fire, as the heat softens the seed coat, thus allowing water to penetrate the seed. Other methods of scarification include soaking the seeds in hot water, cutting or sanding the seed coat, or exposing them to sulfuric acid. These methods have been found to increase germination rates and shorten the time required for seedling emergence. It is important to note that seedling growth can be slow, and seedlings require a well-draining substrate to thrive. Once the seedlings have developed into saplings, they can be transplanted into their permanent locations. Air layering, grafting, and cuttings also been successfully utilized and are considered less costly but less effective. (Sidibe & Williams, 2002; Arum, 1989).

To collect Baobab seeds, one can either retrieve them from fruits that have fallen off the tree or use poles and sticks to dislodge fruits from the trees canopy. Once collected, the seeds should be air-dried and stored in clean, dry, and labelled containers in cool, dry places to prevent damage from moisture, insects, fungal infections, rats, and mice. However, collecting seeds from fallen fruits may not be effective as the seeds may have lost viability or become infected. For shorter trees, seeds can be harvested from the ground or by climbing up a ladder. It is important to note that the collection method can affect the seeds quality, and careful selection of seeds is necessary for successful propagation (Sidibe & Williams, 2002; Arum, 1989).

Seed pre-treatment is a crucial process that can significantly impact the germination rate of baobab seeds. Scarification with concentrated sulphuric acid for 6-12 hours is a common pre-treatment method that has been shown to result in a germination rate of over 90%. However, in rural areas, manual scarification or boiling seeds in water for 15 minutes can be used as an alternative.

Direct seeding into the field has not proven to be very successful, so it is recommended to raise seedlings in a nursery potting mixture of topsoil, sand, and compost. (3 parts topsoil, 1 part sand, and 1 part compost); they can be sown in beds, pots, or polybags. The germination of baobab seeds can be sporadic and take up to a month. Once seedlings emerge, they should be shaded for 8 days, given half shade for 4-7 days, and then exposed to full light after 12-15 days.

Baobab seedlings should be transplanted at the beginning of the rainy season when they are at least 3-4 months old and have reached a height of 40-50cm. Seeds should be sown 1 to 2 inches deep, and soil temperature should be maintained at a minimum of 15 degrees Celsius. Soil should be kept evenly moist but not wet. Planting should be done at a spacing of 10m x 10m. After transplanting, it is crucial to protect the baobab trees from game, livestock, and fire until they are well established (Sidibe & Williams, 2002, Arum, 1989).

The tree should not be planted near houses. Lateral roots may reach over 100m. Pollarding can increase leaf production and prevent toppling of hollow trees, but may reduce fruit production for a few years.

Baobab tree nursery in Kilify Ⓒ J. Muia, 2023

Pest and disease management

Baobab trees have a natural resistance to pests and diseases and are able to withstand environmental stressors due to their thick bark, water storage capabilities, and adaptability. While baobab trees are generally hardy and resistant to pests and diseases, some pests, fungal and viral diseases can affect the tree, and several insect pests that can attack the wood, fruit, and young shoots.

The Baobab tree supports a diverse ecosystem with wide range of insects that do not significantly affect its productivity. While the Baobab tree itself may remain resilient, nearby cultivated crops or native plants could become susceptible to infestation or damage by these pests. It is crucial to monitor and manage pest populations to mitigate potential negative impacts on the surrounding flora. Some of the common Pest that inhabit pests include:

What to do:

• Encourage natural predators of the cotton bollworm, such as parasitic wasps, ladybugs, and birds, by providing habitat and avoiding the use of broad-spectrum insecticides.
• Regularly monitor the trees for signs of infestation and remove any affected fruits or larvae by hand.
• Proper sanitation practices, such as removing fallen fruits and plant debris, can also help reduce the population.
• Natural insecticides derived from plants, such as neem spray or a garlic-chilli-onion-repellent and Bt, can be used as organic alternatives to control cotton bollworms.

Cotton strainer bugs are true bugs that are primarily known for their damage to cotton crops. Stainer bugs are between 14 and 24 mm long. They are bright red, yellow or light grey with an orange tinge depending on the species, and with black bands. Stainer bugs are late season pests. They appear when the bolls are ripening. Female lays whitish yellow eggs in moist soil or in crevices in the ground. They hatch to produce reddish-orange nymphs. Initially the nymphs are wingless, but wings develop gradually as the nymphs grow. The nymphs are found together in the area where the eggs have been laid and later disperse to look for food. Both nymphs and adults feed on the bolls, but adults cause the most serious damage. They pierce through the boll and suck the seeds reducing germination capability and the quality of the seed oil and the cake. Furthermore, they cause severe indirect damage by transmission of a fungus (Nematospora sp.), which leads to internal boll rot and stain of the lint with typical yellow colour, hence the name cotton stainers.

Cotton stainers (Dysdercus spp.). Nymphs (two on the left) and adult cotton stainer. Stainer bugs are 14 -24 mm long. Ⓒ A.M. Varela, ICIPE

What to do: Cotton stainers are attacked by a range of natural enemies. The most important are assassin bugs, ants, spiders, birds and parasitic flies. If cotton is grown where baobab occurs, the soil and trunk of the baobab tree should be sprayed to kill the nymphs hatching from eggs laid around the stem. Introduce natural predators of cotton strainer bugs, such as predatory bugs and parasitic wasps, to the Baobab trees ecosystem to help control the pest population. Neem oil or neem-based insecticidal sprays can be used as an organic control method. Ensure thorough coverage of the affected areas, including the undersides of leaves and stems.

This disease manifests itself through the appearance of orange-brown spots primarily on the undersides of branches. As the infection progresses, these spots darken and merge to form larger patches, giving the affected areas a blackened appearance.

Reports of sooty mould affecting baobabs have emerged from various regions in southern Africa, including Malawi, South Africa, Zambia, and Zimbabwe. The presence of black mould on the stems and branches of African baobabs has been closely associated with a decline in the health of these remarkable trees. Fortunately, sooty mould fungi do not penetrate beyond the outer layer of the baobabs bark, known as the epidermis. While in severe cases, the extensive growth of the fungi on leaves can hinder the plants photosynthetic ability, it does not directly interact with the plant cells to elicit a physiological response (Chomnunti et al., 2014, Hughes, 1976, Cruywagen et al, 2015).

What to do:

• Regular pruning helps remove heavily infested branches or parts of the tree where honeydew and sooty moulds are prevalent. Pruning also promotes better air circulation and sunlight penetration, creating an unfavourable environment for the growth of sooty moulds
• Maintain proper sanitation practices in the vicinity of the Baobab. This significantly reduce the chances of fungal spores being transported to healthy trees. This entails clearing away fallen leaves, debris, and other organic matter that may serve as potential breeding grounds for the fungi.
• Furthermore, promoting optimal tree health through appropriate watering, adequate nutrition, and preventing any physical damage to the baobabs can enhance their resilience against sooty mould infections.

Common Tree Diseases – Family Plot

FAQ

Which diseases does the baobab tree heal?

Why are the leaves on my baobab tree turning yellow?

Why is my baobab dying?

What helps the baobab tree survive?

Are baobab trees deciduous?

Baobab trees are tropical trees that are dry-season deciduous. They lose their leaves in the dry season, and they return in the wet season. Baobab leaves are palmately compound with 5 – 13 leaflets per leaf, depending on the species.

What are the qualities of boabab oil?

Baobab oil is used primarily on the skin. It has antioxidant and anti-inflammatory properties, gives elasticity and turgidity to the skin, and is also used as an oil around the eyes.

How do you identify a baobab tree?

Baobab trees can easily be identified by their unique pachycaul growth with disproportionately thick trunks with no branches most of their length until the top, where they abruptly terminate in an irregular crown with few branches. Their trunks are typically very symmetrically cylindrical to bottle-shaped with a narrow constriction near the top.

Are African baobab trees invasive?

However, they do not appear to be invasive. The African Baobab is a massive pachycaul deciduous tree with single, multiple, cylindrical, or fluted, and often buttressed trunks and unique spreading, rounded crowns with massive irregular branches. The bark is gray and smooth to irregularly tuberculate (warty).