Lablab purpureus (L.) Sweet subsp. purpureus
Lablab purpureus, also known as hyacinth bean, is a leguminous plant that belongs to the family Fabaceae. It is native to Africa and is widely cultivated in tropical and subtropical regions for its edible pods and seeds. The plant is known by many other common names, including Indian bean, dolichos bean, Egyptian kidney bean, and bonavist bean.
Appearance
Lablab purpureus is a fast-growing and twining perennial vine that can reach up to 5 meters in height. The plant has trifoliate leaves that are dark green in color and can grow up to 15 cm long. The flowers are showy and come in shades of pink, white, and purple. They are followed by long, slender, and flattened pods that can grow up to 30 cm in length and contain several seeds. The seeds are oval-shaped and can be black, white, or brown, depending on the variety.
Uses
The edible pods and seeds of Lablab purpureus are commonly used in many cuisines around the world. The pods are typically harvested when they are young and tender and can be eaten raw or cooked. They are often used in soups, stews, curries, and salads. The seeds are also edible and can be cooked and eaten like other legumes. They are rich in protein, fiber, and other nutrients and are a popular food source in many parts of Africa and Asia.
Aside from its use as a food crop, Lablab purpureus is also grown as an ornamental plant. Its attractive flowers and foliage make it a popular choice for trellises, fences, and arbor covers. The plant is also used in traditional medicine for its various health benefits, including its ability to lower cholesterol levels, reduce blood pressure, and improve digestion.
Light Requirements
Lablab purpureus (L.) Sweet subsp. purpureus requires full sun for optimum growth and development. These plants grow best in areas where they receive direct sunlight for at least 6 hours a day. Shade should be avoided as it may cause stunted growth and poor flowering.
Temperature Requirements
The plant thrives in warm temperatures between 25°C and 35°C. Temperatures below 15°C may slow growth and inhibit flowering. It is essential to maintain consistent temperatures to ensure that the plant reaches its full growth potential.
Soil Requirements
Lablab purpureus (L.) Sweet subsp. purpureus grows well in sandy loam, loam, and clay soils. The soil should have good drainage to prevent waterlogging, which can damage the roots. The ideal pH range is between 6.0 and 7.5, but the plant can tolerate slightly acidic or slightly alkaline soils. It is recommended to add organic matter, such as compost or manure, to improve soil fertility.
Cultivation Methods
Lablab purpureus subsp. purpureus, commonly known as Hyacinth bean, can be cultivated in well-drained soils with a pH range between 6.0 to 6.8. It is generally planted during February to May in tropical and sub-tropical regions. The seedlings are transplanted to the field after they attain a height of 20-25 cm and establish roots. The spacing recommended is 45-60 cm rows with plants 30-45 cm apart from each other. It requires a warm and humid climate, so the plant should be grown in the full sun to partial shading. The plant can tolerate light frosts and drought conditions but performs best with adequate water supply and moderate weather conditions.
Watering Needs
Hyacinth bean requires moderate watering during periods of low rainfall. The plant should be watered regularly but not excessively. The frequency of watering is dependent on the climate and evaporation rates of the soil. During dry spells, the plant needs more watering to maintain vigor and prevent premature death of the plant. Overwatering can lead to root rot and stunted growth. The ideal time to water the plant is in the morning or late afternoon when the temperatures are cooler.
Fertilization
Proper fertilization is essential to ensure optimal growth of the Hyacinth bean plant. A balanced fertilizer with an NPK ratio of around 10-10-10 is recommended. This should be applied during planting and every four weeks during the growing season. Organic fertilizers, such as compost or well-rotted manure, are also beneficial to improve soil fertility. It's important to avoid over-fertilizing the plant, which can result in excessive vegetative growth and less yield.
Pruning
Pruning is an essential cultural practice in the cultivation of Lablab purpureus subsp. purpureus. It stimulates the growth of new shoots, enhances production, and eliminates unwanted plant parts. The plant should be pruned at its initial vegetative stage above the 3rd or 4th node to encourage branching. The excess shoots, such as dead, damaged, or diseased, should be removed to promote ventilation and prevent the spread of pests and diseases. Once the plant achieves maturity, it can be cut back by half to encourage new growth and increase yield.
Propagation of Lablab purpureus subsp. purpureus
Propagation is an important technique to increase the number of Lablab purpureus subsp. purpureus plants. There are two main methods for propagating Lablab purpureus subsp. purpureus, which include:
1. Seed Propagation
One of the most common propagation methods for Lablab purpureus subsp. purpureus is through seed propagation. To do this, seed pods are collected when they are mature and dry. The pods should be stored in a cool and dry place until they are ready for use. Before planting, the seeds should be soaked for 24 hours in water to help speed up the germination process.
The seeds should be planted in well-drained soil mixed with compost or organic matter. They should be planted 2-3 cm deep and spaced about 60 cm apart. The seeds should be watered regularly, and the soil should be kept moist until the seedlings emerge.
Seed propagation is a reliable method to ensure genetic uniformity and produce an abundant number of plants.
2. Stem Cutting Propagation
Another method for propagating Lablab purpureus subsp. purpureus is through stem cuttings. Stem cuttings are taken from the parent plant and used to create new plants.
The stem cuttings should be taken from young and healthy branches. Each cutting should have at least two nodes, and the leaves should be removed from the lower node. The cuttings should be planted in well-drained soil mixed with compost or organic matter. The soil should be kept moist until new roots and leaves emerge.
Stem cutting propagation allows for more rapid propagation and ensures genetic uniformity with the parent plant.
Common Diseases and Pests of Lablab purpureus (L.) Sweet subsp. purpureus
Lablab purpureus, also called hyacinth bean, is a member of the legume family and is grown for its edible seeds and leaves. Like any other crop, it is vulnerable to several diseases and pests that can limit its productivity. Some of the common diseases and pests of the plant are:
Diseases
1. Anthracnose: This is a fungal disease that attacks the plant's leaves, stems, and pods. It causes the affected parts to have brown lesions, and the pods may rot and fall off the plant prematurely. To manage anthracnose, remove and destroy infected plant parts and apply fungicides.
2. Bacterial blight: Bacterial blight is caused by the bacterium Xanthomonas campestris. It affects the leaves, stems, and pods of the plant and causes water-soaked lesions that turn brown and become dry. The affected plant parts may also fall off prematurely. To manage bacterial blight, prune and destroy infected plant parts, avoid overhead irrigation, and apply copper-based fungicides.
Pests
1. Aphids: Aphids are small, soft-bodied insects that feed on the plant's sap and excrete honeydew, which attracts ants. Infested leaves may curl, and the plant may become stunted and yellow. To manage aphids, prune infested parts, introduce natural predators like ladybugs or lacewings, or use insecticidal soap.
2. Bean pod borer: Bean pod borer is the larva of a moth that feeds on the seeds inside the pods. It causes the pods to become discolored, and the seeds may be destroyed. To manage bean pod borer, remove and destroy infested pods, use insecticidal sprays, or introduce natural predators like Trichogramma wasps.
By being vigilant and taking preventative measures, it is possible to manage diseases and pests of Lablab purpureus and ensure a bountiful harvest.
