Origin of Vigna retusa (E. Mey.) Walp.
Vigna retusa (E. Mey.) Walp. belongs to the family Fabaceae and is commonly found in various parts of Africa. It is known by different names such as cowpea, southern peas, and black-eyed peas.
General appearance of Vigna retusa (E. Mey.) Walp.
The plant is a robust annual herb that grows up to 1.5 meters tall. The leaves of the plant are pinnately compound, with 3 leaflets, and are approximately 10-15 cm in length. The flowers of Vigna retusa (E. Mey.) Walp. are small and white or creamy-yellow in color, sometimes with a few light pink spots. The seeds are bean-like and are generally 5-9 mm in length and can vary in color with different cultivars.
Uses of Vigna retusa (E. Mey.) Walp.
Vigna retusa (E. Mey.) Walp. is well-known for its edible seeds, which are consumed in different forms across Africa. Young leaves and pods are also eaten boiled, steamed, or fried. This plant is also used in traditional medicine for treating different ailments such as hypertension, diarrhea, and diabetes. Additionally, cowpea plants are commonly used in crop rotations to fix nitrogen in the soil and improve soil fertility. The leaves and stems can be used for animal feed, and the plant is also used for erosion control in areas with high wind and water erosion.
Light Requirements
Vigna retusa typically requires full sun to grow, which means that it needs at least 6 hours of direct sunlight per day. The plant can grow in partial shade, but it may flower less and produce smaller fruit. Therefore, it is important to plant Vigna retusa in a location where it can receive full sun.
Temperature Requirements
Vigna retusa thrives well in warm temperature conditions, with an optimal temperature range of between 20°C to 30°C. It can tolerate temperatures of up to 40°C, but lower temperatures below 15°C may cause stunted growth or even death. Therefore, it is important to plant it during the warm season when the temperature conditions are favorable.
Soil Requirements
The soil type required by Vigna retusa should be well-draining with a pH range of 6.0 to 7.5. The recommended soil type is sandy loam. This type of soil allows for water and nutrient absorption while also preventing waterlogging, which may cause root rot. Adequate moisture must be maintained in the soil, especially during flowering and fruiting. Fertilizers can be added to the soil to provide the necessary nutrients required for optimal growth, and regular weeding should be carried out to prevent competition and reduce the incidence of pest and diseases.
Cultivation Method
Vigna retusa, commonly known as the small white kidney bean, is an annual plant that thrives in subtropical and tropical areas. This plant requires well-draining soils with a pH of 6.0 to 7.5 for optimal growth and development. The plant grows well under direct sunlight with partial shade.
Watering Needs
Vigna retusa requires moderate watering. The plant should be watered deeply once a week. However, frequency may be affected by the soil type and environmental conditions, and the plant should not be allowed to dry out completely or overwatered to avoid root rot. Mulching can help to retain soil moisture.
Fertilization
Vigna retusa requires adequate nitrogen but limited phosphorus, potassium, and calcium. Therefore, a balanced fertilizer with 20-20-20 NPK or 16-8-12 NPK with minor elements should be applied. Fertilizers should be applied in small quantities at first, gradually increasing the quantity after a few weeks to avoid burning the roots. Organic fertilizers rich in nitrogen such as compost or well-rotted manure can also improve soil fertility.
Pruning
Pruning is essential in maintaining the right shape and size of Vigna retusa. It is recommended to pinch back growing tips after four to six weeks, which promotes bushy growth rather than upward growth. However, excessive pruning may lead to low yields. Furthermore, yellowing and dying leaves or stems should be promptly removed as they may harbor pests and diseases or slow down plant growth.
Propagation of Vigna Retusa plants
Vigna Retusa plants can be propagated by seeds, cuttings and division.
Propagation by seeds
Seeds should be sowed in well-draining soil with good organic matter. The seeds should be sowed at a depth of 2 inches and kept moist. Germination usually takes 7-10 days. Once the plants grow a few sets of leaves, they can be transplanted to their permanent location.
Propagation by cuttings
Cuttings of Vigna Retusa should be taken from the tip of the plant in the spring when growth is most active. The cuttings should be 6 inches in length and the bottom of the cutting should be dipped in rooting hormone. The cuttings should then be planted in well-draining soil in a shaded area. Keep the soil moist and within 4 weeks the cuttings should begin rooting and new growth should appear.
Propagation by division
Dividing Vigna Retusa is best done in the spring or fall. Carefully dig up the plant and then divide the clumps of the plant into sections with roots attached. Each section should have a few stems and a good mass of roots. Replant the sections into well-drained soil ensuring that the top of the root mass is just below the soil surface and water well.
Disease Management:
Vigna retusa is susceptible to several diseases including Bacterial Leaf Spot, Anthracnose and Root Rot among others. Bacterial Leaf Spot is a bacterial disease that causes leaf necrosis and can be managed by using copper-based fungicides. Anthracnose, on the other hand, is a fungal disease that causes foliar blight and pod rot. This disease can be controlled by removing and destroying infected plant debris and applying fungicides such as chlorothalonil or azoxystrobin. Root rot can be avoided by ensuring proper soil drainage and avoiding overwatering of the plant.
Pest Management:
Beans beetle, Bean fly and Aphids are common pests that affect Vigna retusa. Bean Beetle can be controlled by using botanical insecticides or Neem oil while Bean fly control involves the use of insecticides such as malathion, dimethoate or acephate. Aphids, which are sap-sucking insects, can be managed by using insecticidal soap or spraying the plants with neem oil. It is also important to regularly inspect plants for signs of pest infestation and take appropriate action as soon as possible to prevent further damage.
