Voacanga Thouarsii Roem. & Schult. Var. Obtusa (k.schum.) Pichon

Overview:

Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon is a plant species that belongs to the Apocynaceae family. This plant is known by various common names, including African Whitewood, African Oak, and Bonganga. It primarily grows in tropical regions of Africa, including Nigeria, Cameroon, and Congo.

Physical Appearance:

The African Whitewood is a medium to large-sized tree that can reach up to 30 meters in height. It has a dense and symmetrical crown that is shaped like a dome. The tree has a straight trunk that can have a diameter of up to one meter. The bark of the tree is gray-brown and fibrous. The leaves are simple, alternate, and oblong. The tree produces small flowers that are white or pink in color, with a sweet fragrance. The fruit is a woody capsule, which splits open, releasing numerous small seeds that carry a fluffy coma.

Uses:

Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon is known for its medicinal and ritualistic uses. The plant's roots, leaves, and bark contain various hallucinogenic and medicinal alkaloids, including ibogaine, which is used in treating drug addiction and depression. In traditional African herbal medicine, the bark and roots are used as a stimulant, diuretic, and anti-inflammatory agent. In addition, the bark and roots were used as an insecticide to protect stored grains and as a fish poison to make fishing easier.

The tree is also used for timber, and the wood is considered to be of high quality even though it is susceptible to termites and other wood-boring insects. The wood is used for making fine furniture, flooring, and tool handles. The leaves and bark of the tree are used as fodder for livestock, and the tree has potential for use in reforestation and erosion control.

Light Conditions

Voacanga thouarsii var. obtusa can tolerate a wide range of light conditions. However, it thrives best in partial to full sunlight. When planted in shaded areas, expect slower growth rates and weaker stems.

Temperature Requirements

This plant can grow in a variety of temperature ranges. However, it prefers warm conditions with average temperatures between 20-25°C (68-77°F) during the day and 10-15°C (50-59°F) during the night. Temperatures below 10°C (50°F) will cause stunted growth or even plant death.

Soil Requirements

The Voacanga thouarsii var. obtusa can grow in different soil types, including well-draining, fertile, and moist soils. It thrives best in deep soils rich in organic matter, with a pH range between 5.5 and 7.5. However, it can still grow in slightly acidic or alkaline soil conditions. Ensure the soil is not waterlogged as this can cause root rot and subsequent death of the plant.

Cultivation

Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon is a tropical evergreen tree that is usually found in the understory of forests. It can grow up to 15 meters high and prefers well-drained soils with a pH of 6.5 to 7.5.

The plant is propagated via seeds, which should be fresh and not older than six months. The seeds require scarification before being sown in a mixture of sand and peat. The pots should be kept in a warm, humid environment until germination.

Watering needs

The plant needs regular watering, especially during the growing season. The soil should be kept moist but not waterlogged, as this can cause root rot. In the winter, watering should be reduced to prevent water stagnation.

The plant can also benefit from occasional misting, as it likes high humidity.

Fertilization

The plant can be fertilized using a balanced, soluble fertilizer, preferably one that is rich in nitrogen. Fertilization should be done every two weeks during the growing season. In the winter, fertilization should be reduced to once a month.

It is essential to water the plant before fertilizing and to avoid over-fertilization, as this can cause burning of the roots.

Pruning

Pruning of Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon should be done in the dormant season to remove any damaged or diseased branches. The plant can also benefit from shaping to improve its overall appearance.

It is also advisable to prune the plant to control its size, although this should be done with care as it can cause stress to the plant.

Propagation of Voacanga Thouarsii Roem. & Schult. Var. Obtusa (K.Schum.) Pichon

Voacanga Thouarsii Roem. & Schult. var. Obtusa (K.Schum.) Pichon is commonly propagated from seed or stem cuttings. Here are some tips:

Propagation from Seed

The easiest way to propagate Voacanga Thouarsii Roem. & Schult. var. Obtusa (K.Schum.) Pichon is through seed. Here are the steps to follow:

1. Collect ripe fruits from the plant, and extract the seeds.
2. Soak the seeds in water for 24 hours to soften the seed coat.
3. Choose a suitable potting mix and fill the pot.
4. Make shallow holes on the soil's surface, about 1cm deep.
5. Place the seeds in the holes and gently cover them with soil.
6. Water the soil to keep it evenly moist.
7. Place the pot in a warm, well-lit area, away from direct sunlight.
8. Germination usually takes 2-3 weeks.

Propagation from Stem Cuttings

Propagation from stem cuttings is another way to reproduce Voacanga Thouarsii Roem. & Schult. var. Obtusa (K.Schum.) Pichon. Here's how:

1. Select a healthy stem that has at least two nodes.
2. Cut the stem about 10-15cm long, just below a node.
3. Remove any leaves from the bottom half of the cutting.
4. Dip the cut end in rooting hormone powder.
5. Insert the cutting in a moist potting mix, covering the bottom half of the stem.
6. Water the soil and keep it moist until roots develop.
7. Place the pot in a well-lit, warm area, away from direct sunlight.
8. After rooting, transplant the cuttings to individual pots or to the garden.

Disease Management for Voacanga Thouarsii Roem. & Schult.

Like any other plant species, Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon can be affected by various diseases that can significantly affect its growth and yield. Therefore, it is essential to implement appropriate measures to prevent and control diseases that might affect the plant. Here are some common diseases that might affect the plant and ways to manage them.

Root Rot

The root rot disease is mostly caused by soil-borne fungi that thrive in excessively wet or poorly-drained soils. The first sign of root rot is yellowing and wilting of the leaves, followed by a slow or stunted growth rate of the plant. To manage root rot, ensure proper drainage of the soil and avoid overwatering the plant. Additionally, you can use fungicides such as copper oxychloride to manage the disease.

Leaf Spot

Leaf spot disease is characterized by the appearance of small, circular, and dark spots on the plant's leaves, which later become tan in color. Leaf spot is mostly caused by bacterial infections, which can quickly spread and cause defoliation of the plant. To manage leaf spot, you should remove and destroy all infected leaves and avoid wetting the leaves during watering. You can also use copper-based fungicides to control the spread of the disease.

Pest Management for Voacanga Thouarsii Roem. & Schult.

Voacanga thouarsii Roem. & Schult. var. obtusa (K.Schum.) Pichon can also be affected by various pests that can cause significant damage to the plant. Therefore, it is essential to implement appropriate measures to prevent and control pests that might affect the plant. Here are some common pests that might affect the plant and ways to manage them.

Aphids

Aphids are tiny insects that suck the sap from the plant's leaves, causing them to wilt and turn yellow. Additionally, aphids excrete a sticky substance known as honeydew that can encourage the growth of black sooty mold. To manage aphids, you can use insecticidal soap or neem oil to control their population. Additionally, you can introduce natural predators such as ladybugs, lacewings, or parasitic wasps.

Spider Mites

Spider mites are too small to see with the naked eye, but you can notice their presence by the fine webbing they produce on the underside of leaves. Additionally, spider mites cause stippling on the plant's leaves and, if left unchecked, can cause defoliation. To manage spider mites, you should regularly mist the plant's leaves with water to create a humid environment that is unsuitable for their survival. You can also use insecticidal soap or neem oil to control their population.