Trichilia roka (Forsskal) Chiov. - Overview
Trichilia roka (Forsskal) Chiov. is a small to medium-sized tree that belongs to the Meliaceae family. The plant is native to the tropical and subtropical regions of Africa, Asia, and Madagascar. It is also found in the Arabian Peninsula, Iran, and Pakistan.
Common Names
The plant is known by several common names which include:
- Roka in Arabic
- Rojka in Sudanese Arabic
- Batak gumantung in Batak Toba
- Hanzal in Somali
- Kaliyar in Hindi
- Karuvelippattaai in Tamil
- Ndazi in Swahili
- Nkoké in Kikongo
- Botsende in Setswana
Appearance
The Trichilia roka tree grows up to a height of about 10-15 meters and has a trunk diameter of 30-40 cm. The bark is rough, greyish-brown in color, and deeply fissured. The leaves are compound and arranged spirally, with 5-15 pairs of leaflets that are elliptical in shape. The pinkish-white flowers are small, fragrant, and arranged in large terminal clusters. The fruit is a drupe, green when young and turning brown as it ripens. The tree produces fruit about once a year, and each fruit contains one seed.
Uses
The Trichilia roka tree has several traditional and medicinal uses. The bark and roots of the plant are used for various medicinal preparations to treat different ailments. The leaves are used as an insect repellant and the oil extracted from the seeds is used in soap-making and as a lubricant for machinery. The fruit pulp is used in cosmetics, and the wood is used for carving, furniture making, and fuel.
Additionally, the tree is planted as an ornamental shade tree in parks and gardens, and it is also used for soil conservation and reforestation projects due to its fast-growing nature.
Light Requirements
Trichilia roka requires full sunlight for healthy growth and development. This plant can tolerate partial shade, but it may result in stunted growth and reduced vigor.
Temperature Requirements
This plant thrives in warm temperatures between 25-35°C, although it can tolerate slightly cooler temperatures. Temperatures below 15°C can damage the plant, while temperatures above 40°C can cause leaf scorching and dehydration. It is important to protect Trichilia roka from frost and extreme temperature changes.
Soil Requirements
Trichilia roka prefers well-draining soil that is rich in organic matter. The soil should be slightly acidic to neutral with a pH range of 5.5-7.5. The plant can tolerate a range of soil types, but it grows best in loamy or sandy soils. It is important to ensure that the soil is consistently moist but not waterlogged, as excess moisture can lead to root rot and other fungal diseases.
Cultivation Methods
Trichilia roka is a slow-growing tree that requires a lot of care during its early years of growth. It needs to be planted in well-draining soil with plenty of organic matter. The ideal soil pH for this plant is between 6.0 and 7.5. It grows in full sun to partial shade areas.
The planting hole should be dug deeper than the root ball's length and slightly wider to allow for the root system's spread. Ensure that the tree is planted at the same depth it was in the nursery. Water the plant immediately after planting, and ensure consistent moisture during the establishment period.
Watering Needs
Trichilia roka needs regular watering but is susceptible to overwatering. Water the plant deeply, but allow the soil to dry out slightly between watering intervals to prevent waterlogged roots.
During the dry season, water the plant every 2-3 days, but reduce the watering frequency during rainfall. Continual moisture is essential to prevent leaf loss.
Fertilization
A slow-release fertilizer that contains nitrogen, phosphorus, and potassium is ideal for Trichilia roka. Fertilize the tree twice a year, once in the spring and once in the fall.
The quantity of fertilizer applied depends on the tree's size and age. Young trees need less fertilizer than mature trees, but too much fertilizer can damage the plant. Follow the manufacturer's instructions to ensure the right amount of fertilizer is applied.
Pruning
Prune Trichilia roka during the dormant season to remove diseased or damaged branches, promote airflow, and control the tree's size and shape.
As the tree matures, remove the lower branches to allow for easier access and better airflow. Prune the tree to maintain a central leader and eliminate branches that cross or rub against each other.
Prune only the minimal amount of foliage necessary to prevent stress on the plant. Use clean pruning equipment to prevent the spread of disease.
Propagation of Trichilia roka (Forsskal) Chiov.
Trichilia roka (Forsskal) Chiov. can be propagated through both sexually and asexually.
Sexual Propagation
The plant can be propagated by seed, which are easily available in the market. The seedlings can be raised in a pot or directly into the ground. Sow the seeds in a well-draining soil mixture with sand, perlite, and cocopeat in equal proportions. The seeds must be covered loosely with soil and watered gently. The pot must be kept in a shaded area and watered regularly. Germination may take 2 to 4 weeks, and the seedlings will require regular fertilization and ample sunlight.
Asexual Propagation
Trichilia roka (Forsskal) Chiov. can be propagated asexually through stem cuttings. Select a healthy stem and cut it at a 45-degree angle from where the leaf grows. The stem cuttings must be around 6 inches long and must contain a few nodes. Remove the leaves from the lower half of the stem and dip the cut end in rooting hormone. Plant the cutting in a well-draining soil mixture with sand, vermiculite, and perlite in equal proportions, water, and keep in a shaded area until new roots emerge in 3 to 4 weeks. After the new growth emerges, gradually expose the new plant to sunlight.
Disease and Pest Management for Trichilia roka (Forsskal) Chiov.
Trichilia roka is a tropical plant that is susceptible to a variety of diseases and pests. To maintain the health of this plant, it is essential to practice proper management techniques that address these concerns.
Common Diseases
One of the most common diseases that affect Trichilia roka is leaf spot. This disease is caused by a bacterial or fungal infection and can cause the leaves to wilt and turn brown or black. To manage this disease, it is essential to implement proper watering practices that avoid wetting the leaves. Fungicides and bactericides may be necessary in severe cases.
Another disease that affects Trichilia roka is powdery mildew. This fungal infection appears as a white powdery substance on the leaves. It can be managed by implementing proper air circulation around the plant and using fungicides if necessary. Pruning damaged or infected leaves can also help prevent the disease from spreading.
Common Pests
Trichilia roka is also susceptible to various pests such as mites, aphids, and scale insects. These pests can cause damage to the leaves, flowers, and fruits of the plant. Implementing proper watering and fertilization practices can help prevent infestations. Additionally, introducing beneficial insects such as ladybugs or lacewings or using insecticides may be necessary to manage severe infestations.
Caterpillars and beetles can also cause damage to Trichilia roka. Handpicking these pests may be effective in small infestations. However, insecticides may be necessary in more severe cases. It is essential to use insecticides according to the label instructions and only when necessary to avoid harming beneficial insects.
Conclusion
Managing diseases and pests is essential to maintain the health and productivity of Trichilia roka plants. Implementing proper watering, fertilization, and air circulation practices can prevent many diseases and pests from infesting the plant. Identifying and addressing issues early and using insecticides or fungicides only when necessary can help prevent significant damage to the plant.
