Overview
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is a legume plant that belongs to the family Fabaceae. It is a perennial plant that is native to Africa and is commonly known as the Madagascar or wild cowpea.Description
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is a branching vine that can grow up to 2 meters tall. Its leaves are compound and consist of three leaflets, each about 5-12 cm long. The flowers are pale yellow and are borne in axillary racemes that can reach up to 15 cm long. The fruit is a straight or slightly curved pod that can grow up to 20 cm long and contains up to 10 seeds.Origin and Distribution
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is native to sub-Saharan Africa but can also be found in Madagascar and the Comoros Islands. It is widely grown in East and Southern Africa as a vegetable crop and is especially popular in Malawi, Tanzania, and Zambia.Common Names
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is known by various common names, including wild cowpea, Madagascar cowpea, and climbing cowpea.Uses
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is an important crop in Africa, where it is grown for its edible pods and seeds. The young pods are harvested and cooked as a vegetable, while the mature seeds are used to make a nutritious flour that can be used to make porridge or bread. The plant is also used as a traditional medicine in some African cultures to treat various ailments, including diabetes, anemia, and high blood pressure.Light Requirements
Vigna vexillata var. dolichonema prefers full sunlight to partial shade. It thrives in areas with bright light, which promotes its growth and development. If planted in shaded areas, it tends to grow weak, spindly stems that do not produce high yields.
Soil Requirements
The plant grows well in a variety of soils, including sandy loam, loam, and clay loam. However, it prefers well-draining soils with good water-holding capacity. The pH of the soil should be between 6.0 to 7.5 while the soil should be fertile, rich in organic matter, and free of toxic chemicals. Before planting, adding well-decomposed compost to the soil can significantly improve its fertility and structure.
Temperature Requirements
Vigna vexillata var. dolichonema grows well in tropical and subtropical regions with temperatures ranging between 25°C to 35°C. It requires a minimum temperature of 18°C for germination, while temperatures above 40°C may cause heat damage to the plant. The plant is sensitive to frost and cannot grow in temperatures below 13°C. Therefore, it is mainly grown in the summer season.
Cultivation Methods for Vigna vexillata var. dolichonema
Vigna vexillata var. dolichonema is best cultivated in well-drained soil. It prefers a sunny location but can also grow in partially shaded areas. The plant needs a structure to climb, such as trellis or fences. Direct sowing of seeds into the soil is recommended, and seedlings can be transplanted after six weeks.
Watering Needs for Vigna vexillata var. dolichonema
Vigna vexillata var. dolichonema requires moderate watering. Overwatering can cause root rot, so it is best to water the plant only when the soil is dry to the touch. During the dry season, the plant may need more frequent watering.
Fertilization for Vigna vexillata var. dolichonema
Vigna vexillata var. dolichonema benefits from regular fertilization with organic matter or slow-release fertilizer. Nitrogen-rich fertilizers can promote leafy growth, while phosphorus-rich fertilizers can encourage flowering and fruiting. Fertilization should be done every four to six weeks during the growing season.
Pruning for Vigna vexillata var. dolichonema
Pruning is not necessary for Vigna vexillata var. dolichonema. However, trimming the plant's tips can encourage more branching and increase the yield of fruits. Removing dead or diseased branches can also improve the plant's overall health.
Propagation of Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc.
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. or simply known as the Sword Bean is propagated through two methods: seed propagation and vegetative propagation.
Seed Propagation
The Sword Bean plant can be propagated via seeds which can be obtained from mature pods. The seeds should be obtained by picking the pods from the plant. The obtained seeds should be sun-dried and stored in a cool and dry place until planting. The planting period typically lasts from March to May in favorable climatic conditions. The seeds should be planted in the soil to a depth of about 3-4 cm. The plants obtained from seeds take approximately 3 to 4 months to produce pods, depending on the growing conditions.
Vegetative Propagation
The Sword Bean plant can also be propagated vegetatively by stem cuttings. Cuttings of 4-6 weeks old with a length of 8-10 cm from the plant should be planted in the soil. For best results, it is recommended to apply a small amount of rooting hormone powder to the end of the cutting before planting to enhance the chances of its growth. The cuttings should be planted in well-composted beds and in shaded areas to protect the plants from harsh sun rays. The newly planted cuttings should be watered every day until they establish roots. A mature Sword Bean plant grown via vegetative propagation method typically produces pods within 3 to 4 months after planting.
Disease and Pest Management for Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc.
Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc. is a plant species that may be subject to various diseases and pests. Here are some of the common ones and ways to manage them.
Diseases
Anthracnose
Anthracnose is a fungal disease that affects leaves, stems, and pods, resulting in dark, sunken, and circular spots. This disease thrives in damp conditions. Gardeners can control anthracnose by following these measures:
- remove and get rid of the infected leaves, stems, and pods
- rotate crop plants to a different spot if possible
- apply a copper-based fungicide to the plant when it shows the first sign of infection.
Powdery mildew
Powdery mildew is also a fungal disease that appears as talc-like powder on leaves and stems. This disease is the result of humidity in the area. Gardeners can control powdery mildew by following these measures:
- Prune infected leaves
- Clean up debris that falls around the plants
- apply a fungicide, such as sulfur, when the first sign of infection appears on the plant.
Bacterial Blight
Bacterial blight may occur due to bacterial infection, resulting in irregular brown areas with yellowing around the edges on leaves. Overwatering or high humidity may cause this disease. Gardeners can control bacterial blight by following these measures:
- Remove and destroy all affected parts of the plant
- Adhere to good garden sanitation practices: clean garden tools before using them and clean the plant’s surroundings of all debris
- Apply a copper-based fungicide to the plant when the infection first appears.
Pests
Beetles
Beetles may damage the leaves and stems of the plant. These beetles include cucumber beetles, bean beetles and flea beetles. Gardeners can get rid of beetles by following these measures:
- Use a hand-held insect vacuum to remove the beetles from the plant that may have appeared
- Plant basil, marigold, or garlic as a biological control agent.
- Use insecticides containing pyrethrin on the beetles.
Spider Mites
Spider mites are very small in size and may cause the foliage to have a stippled appearance, which can lead to the foliage falling off the plant. These mites suck the sap out of the plant, leaving it vulnerable to diseases. Gardeners can get rid of spider mites by following these measures:
- Use a hose to wash spider mites from the plant
- Apply insecticidal soap on the plant
- Release ladybugs in the plant's environment as biological control agents.
Aphids
Aphids are small, soft-bodied insects that feast on plant sap and may cause yellowing of the leaves. Gardeners can manage aphids by following these measures:
- Check plants regularly for aphids and use a hose to knock off the aphids from the plant
- Plant mint near the plant as a biological control agent
- Apply insecticidal soap on the plant when the first sign of aphids appears.
By using these preventive measures, gardeners can manage pests and diseases and protect the health of Vigna vexillata (L.) A.Rich. var. dolichonema (Harms) Verdc.
