Overview
Isomacrolobium nigericum (Baker f.) Aubrév. & Pellegr. is a species of tropical plants in the Fabaceae family, which is commonly known as the African teak or makore. The plant is native to West and Central Africa and can be found in countries such as Cameroon, Congo, Equatorial Guinea and Gabon. It is a well-known timber tree that is popular in the furniture, flooring, and joinery industries due to its dense, hard and durable wood.
Appearance
The African teak tree is a medium to large-sized tree, with a straight trunk that can grow up to 40 meters tall and a diameter of up to 1.5 meters. The plant's bark is light grey to pale brown and flakes off in large pieces. The leaves of Isomacrolobium nigericum are pinnately compound, measured up to 50 cm in length, with 6-8 pairs of leaflets and a terminal leaflet that is distinctly larger than the other leaflets. The flowers are small, yellowish, and fragrant, in clusters that form at the end of the branches in the dry season. The fruits are elongated pods, up to 30cm in length, with a diameter of about 1cm, and contain seeds that are used for propagation of the plant.
Uses
Isomacrolobium nigericum is primarily valued for its wood, which is hard, durable, and resistant to decay. The heartwood of the African teak is reddish-brown in color when freshly cut, turning to a darker color as it ages. It is used in the construction of doors, windows, furniture, flooring, and boat building. In addition to its commercial value, the plant is also used for medicinal purposes. The roots, bark, and leaves of the plant are used in traditional medicine for the treatment of arthritis, fever, and stomach ailments.
The African teak is also an important species for environmental conservation. It is known to play a significant role in the ecology of the forest, including erosion control, soil fertility maintenance, and water regulation. The tree provides habitat and food for a variety of animals, including primates, birds and insects.
Growth Conditions for Isomacrolobium nigericum
Isomacrolobium nigericum (Baker f.) Aubrév. & Pellegr. is an evergreen tree that typically grows in the tropical regions of Africa. They prefer to grow in areas that are shaded and can tolerate low levels of light.
Light Requirements
Isomacrolobium nigericum prefers to grow in shade and can tolerate low levels of light. It requires partially shaded areas to prevent the leaves from burning. Direct sunlight can lead to leaf damage, and the tree may not grow well in such conditions.
Temperature Requirements
The tree thrives in warm and humid climatic conditions. It requires an average temperature range of about 20-28 °C (68-82°F) in areas with high humidity. However, it is not tolerant to extreme temperatures and may not grow well in areas where temperatures drop below freezing.
Soil Requirements
Isomacrolobium nigericum grows well in well-drained soils that are rich in organic matter. The tree can grow in sandy or clay soils provided they are well-drained. The soil pH should range between 5.5 and 6.5, which is slightly acidic. The tree is not tolerant to water-logged soils, and therefore, proper drainage should be ensured.
In conclusion, Isomacrolobium nigericum prefers warm and humid climatic conditions with partially shaded areas. It grows well in well-drained soils rich in organic matter with a slightly acidic pH range.
Cultivation Methods for Isomacrolobium nigericum
Isomacrolobium nigericum can be propagated easily through seeds, stem cuttings, or grafting. Seeds should be sown in well-drained soil at a depth of 2 cm, during the rainy season. Germination may take up to 2 months.
The plant prefers sandy loam soil that is slightly acidic, with a pH range between 6.0 and 6.5. It requires full sun exposure, and can tolerate temperatures as high as 40°C and as low as 12°C. If grown in a container, ensure it has proper drainage, and that the soil is kept moist.
Watering Needs for Isomacrolobium nigericum
Newly propagated plants require frequent watering until they are well established. However, mature plants do not require much watering, as they can tolerate drought conditions. Water the plant only when the top layer of soil is dry. Overwatering can lead to root rot and eventual death of the plant.
Fertilization for Isomacrolobium nigericum
Isomacrolobium nigericum requires regular fertilization to promote growth and flowering. A balanced fertilizer (NPK 10-10-10) should be applied every two months during the growing season. Alternatively, organic manure can be used, but it should be well decomposed before application.
Avoid over-fertilization, as it can lead to excessive vegetative growth and reduced flowering. Also, ensure that fertilizer is not applied during the dry season, as it can damage the roots.
Pruning Isomacrolobium nigericum
Pruning is not necessary for Isomacrolobium nigericum, but it can be done to maintain its shape and size. Pruning should be done during the dormant season (winter) to reduce the risk of damage to the plant.
Dead or damaged branches can be pruned at any time of the year. Ensure that the pruning tools are sharp and sanitized before use, to prevent the spread of diseases.
Propagation of Isomacrolobium nigericum (Baker f.) Aubrév. & Pellegr.)
Isomacrolobium nigericum can be propagated by both sexual and asexual means. The plant produces seeds and can also be grown from cuttings.
Propagation by seeds
The seeds of Isomacrolobium nigericum should be collected when the pods are fully mature, and the seeds have turned brown. The seeds should be scarified using hot water or sulfuric acid to enhance germination rates. This should be done with caution to prevent damage to the seeds.
After scarification, the seeds should be soaked in warm water for 24 hours to hasten germination prior to sowing in sandy soil. The seeds should be planted at a depth of 1-2 cm and kept moist until germination, which usually occurs within 2-3 weeks.
Propagation by cuttings
Isomacrolobium nigericum can also be propagated using cuttings from mature plants. The cuttings should be taken from the plant's softwood, which is the new growth that has not fully matured. The stem cuttings should be 6-8 cm long, with a minimum of two nodes.
The cuttings should then be dipped in rooting hormone and planted in well-drained soil in either pots or the ground. The soil should be kept moist to prevent the cutting from drying out. The cuttings should root within 2-3 weeks, and after that, they can be transplanted into their permanent growing position.
Disease Management
Isomacrolobium nigericum (Baker f.) Aubrév. & Pellegr. is susceptible to several diseases that can lead to yield losses. Here are the common diseases affecting the plant and ways to manage them:
1. Anthracnose
This disease is caused by the fungus Colletotrichum gloeosporioides. It can cause leaf and stem lesions, flower and pod blight, and premature drop of flowers and buds. The disease is favored by high humidity and warm temperatures. To manage the disease, remove and destroy infected plant debris, practice crop rotation, use disease-resistant varieties, and apply fungicides during the early stages of the disease.
2. Root knot nematodes
Root knot nematodes (Meloidogyne spp.) are soil-borne pests that can cause severe damage to the plant. They form galls on the roots, which can lead to reduced nutrient uptake and stunted growth. To manage the pest, practice crop rotation, use nematode-resistant varieties, and apply nematicides.
Pest Management
Several pests can also attack and damage Isomacrolobium nigericum (Baker f.) Aubrév. & Pellegr. Here are the common pests affecting the plant and ways to manage them:
1. Pod borers
Pod borers (Maruca vitrata and Helicoverpa armigera) can cause significant damage to the crop. They feed on the developing pods, leading to reduced yield and quality. To manage the pests, use pheromone traps, handpick and destroy infested pods, use resistant varieties, and apply botanical pesticides such as neem oil and pyrethrum.
2. Cutworms
Cutworms (Agrotis spp.) are nocturnal pests that feed on the stems of young seedlings, resulting in wilting and death. To manage the pest, use cultural practices such as cultivating the soil to expose the cutworms to predators and applying biological control agents such as entomopathogenic nematodes.
3. Aphids
Aphids are sap-sucking pests that can cause stunted growth and yield losses. They secrete honeydew, which attracts ants and can lead to the growth of sooty mold. To manage the pest, use cultural practices such as removing weeds and providing adequate ventilation, use biological control agents such as ladybugs, lacewings, and parasitic wasps, or apply insecticidal soap or neem oil.
