Overview
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet is a subspecies of the Vigna unguiculata plant which belongs to the family Fabaceae. It is commonly known as the Burundi cowpea and is a vegetable crop widely grown in sub-Saharan Africa.
Origin
The Burundi cowpea is believed to have originated from Africa and is widely grown in the countries of East and Southern Africa. It is an important crop for farmers in these regions as it is highly drought-tolerant and able to withstand adverse environmental conditions.
Common Names
The Burundi cowpea is also known by various names depending on the region it is grown in. Some of the common names include nyimbili in Tanzania, niébé in Francophone West Africa, and black-eyed peas in the United States.
Uses
The Burundi cowpea is used as a vegetable crop and is an important source of protein, vitamins, and minerals for people in sub-Saharan Africa. It is often consumed as a side dish and is a common ingredient in traditional stews and soups. The leaves of the plant are also edible and can be cooked and eaten as a vegetable. In addition, the Burundi cowpea is used as a cover crop to improve soil fertility and prevent soil erosion.
Appearance
The Burundi cowpea is an annual plant that can grow up to 2 meters in height. It has a deep taproot and a strong stem that can withstand strong winds. The leaves are trifoliate with ovate leaflets and the flowers are usually purple in color. The pods are 12-15 cm in length and contain 10-12 seeds which are usually cream or beige in color with a distinctive black eye at the hilum.
Light Requirements
Vigna unguiculata subsp. burundiensis Pasquet is a tropical plant that requires bright light for optimum growth. It is tolerant of partial shade but full sunlight is preferred. Inadequate light results in stunted growth and poor yield.
Temperature Requirements
The plant grows well in warm temperatures ranging from 25°C to 35°C. The ideal temperature range is between 28°C to 32°C. It is highly susceptible to frost and should be protected when the temperature drops below 15°C.
Soil Requirements
Vigna unguiculata subsp. burundiensis Pasquet prefers well-draining, sandy or loamy soils with a pH range of 6.0 to 7.5. The plant can survive in poor soils but optimal growth is achieved in fertile soils with good moisture retention capacity. Soil should be kept moist but not waterlogged as over-watering can lead to root rot.
Cultivation Methods
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet, also known as cowpea, is a warm-season crop that is relatively easy to cultivate. It is best grown in well-drained loamy soil with a pH of between 6.0 and 7.0. The crop can be planted directly in the ground after the last frost or started indoors about 4 to 6 weeks before the last frost. The seeds should be planted about 1 to 2 inches deep and spaced 3 to 6 inches apart in rows that are 2 to 3 feet apart. Cowpea plants require full sun exposure and do not tolerate shade well.
Watering Needs
It is essential to water cowpea plants consistently and adequately, especially during their flowering and pod development stages. The plants require an average of 1 inch of water per week. However, the amount of water they require can vary depending on the weather conditions, soil type, and plant growth stage. It is best to water cowpea plants deeply once a week, making sure to soak the soil around their roots. Avoid overhead watering as it can lead to the development of fungal diseases and increase plant susceptibility to pest attacks.
Fertilization
Cowpea plants require moderate fertilization to produce a significant harvest. Use a balanced fertilizer such as 10-10-10 before planting to provide the plants with the necessary nutrients. A side-dressing of nitrogen-rich fertilizer can be applied when the plants start flowering to encourage healthy growth and enhance pod development. Avoid using too much nitrogen, which can cause vigorous vine growth at the expense of flowers and pods. Organic fertilizers such as compost and well-rotted manure can also be beneficial to the crop's growth and yield.
Pruning
Cowpea plants do not require much pruning, but it is essential to remove any dead, diseased, or damaged plant material promptly. Pruning can also help maintain open plant architecture and facilitate better light penetration and air circulation, thereby reducing the occurrence of fungal diseases. Once the plants reach about 6 inches in height, pinch off the tips of their main stems to encourage lateral branching and more pod development. Harvest the pods when they are still young and tender for the best quality and flavor.
Propagation of Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet, commonly known as Burundi cowpea, is propagated by sexual or vegetative methods.
Sexual propagation
Burundi cowpea can be propagated by direct seeding in the field. The seeds of the plant can be sown directly in the soil during the rainy season. The seeds should be sown at a depth of 2 to 5 cm and 30 to 40 seeds per meter row. The spacing between the rows should be between 60 and 75 cm.
Seedbed sowing is another method of propagating the Burundi cowpea. The seeds are sown in seedbeds or on trays, and then the seedlings are transplanted in the field.
Vegetative propagation
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet can also be propagated by vegetative methods such as stem cuttings and vine cuttings.
Stem cuttings should be taken from healthy, disease-free plants with a diameter of about 0.5 cm and a length of 10 to 15 cm. The leaves on the lower part of the cutting should be removed, and the cutting should be planted in a well-prepared soil. For vine cuttings, the cuttings should be about 40 cm long and should be buried in the soil up to a depth of 10 to 15 cm. The cuttings should be irrigated regularly until new shoots develop.
Disease Management
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet is susceptible to several diseases that can significantly reduce yields if not managed effectively. Some of the common diseases that affect this plant include:
- Anthracnose: It is a fungal disease that causes leaf spots, stem blight, and pod rot. To manage anthracnose, you can use fungicides, cultural practices such as crop rotation, and resistant cultivars.
- Mosaic Virus: It is a disease that causes yellow mosaic on the leaves, stunted growth, and reduced yields. Mosaic virus can be managed by using virus-free seeds, controlling insect vectors, and rogueing infected plants.
- Bacterial Wilt: It is a disease that causes wilting, yellowing, and death of leaves. Bacterial wilt can be managed using cultural practices such as crop rotation, resistant cultivars, and the use of biocontrol agents.
Pest Management
Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet is also susceptible to several pests that can cause significant damage to the crops. Here are some of the common pests that affect this plant:
- Aphids: These are small, soft-bodied insects that suck the sap from the plant, causing stunted growth and reduced yields. To manage aphids, you can use insecticides, natural predators such as ladybugs, and cultural practices such as crop rotation and intercropping.
- Spider Mites: They are tiny insects that feed on the underside of the leaves, causing yellowing and dropping of the leaves. Spider mites can be managed by using acaricides, natural predators such as predatory mites, and cultural practices such as maintaining optimal humidity levels.
- Cutworms: These are caterpillars that cut the stems of the plants, causing wilting and death. Cutworms can be managed by using insecticides, handpicking the insects, and using cultural practices such as planting trap crops.
In conclusion, the effective management of diseases and pests in Vigna unguiculata (L.) Walp. subsp. burundiensis Pasquet is essential to ensure high yields and quality crops. By using a combination of cultural practices, natural predators, and chemical treatments where necessary, you can significantly reduce the impact of diseases and pests on your crops.
