Origin
Vigna unguiculata (L.) Walp. ssp. unguiculata, commonly known as cowpea, is a plant species belonging to the family Fabaceae. It is native to Africa, but has been cultivated worldwide for its edible seeds and young pods.
Common Names
Cowpea is called by different names in different regions. It is commonly known as black-eyed pea, southern pea, crowder pea, and China bean in the United States, while in Nigeria it is popularly known as "beans of the savannah" or "corn of the poor".
Uses
The cowpea is mainly grown for its edible seeds, which are a good source of protein, dietary fiber, and other essential nutrients. The young pods of the plant are also consumed as a vegetable in some regions. Cowpea is an important crop for subsistence farmers and is used as a primary source of food in many parts of Africa.
Besides its use as a food crop, cowpea is also used as a cover crop, a green manure, and as fodder for livestock. It is known to improve soil fertility by fixing atmospheric nitrogen and reducing soil erosion. Cowpea is also used in traditional medicine to treat various ailments, such as diarrhea, diabetes, and hypertension.
General Appearance
Cowpea is an annual or perennial herbaceous plant that can grow up to 2 meters tall. The leaves are trifoliate, with each leaflet measuring about 6-15 cm long and 4-10 cm wide. The flowers are borne in racemes or spikes and are usually white, pink, or purple in color. The fruit is a pod, which varies in shape and size depending on the variety. The seeds inside the pod are kidney-shaped and are usually cream, brown, or black in color.
Light Requirements
Vigna unguiculata (L.) Walp. ssp. unguiculata requires full sunlight to thrive. The plant needs a minimum of six hours of direct sunlight per day.
Temperature Requirements
The optimal temperature range for Vigna unguiculata (L.) Walp. ssp. unguiculata growth is between 25°C and 35°C. The plant cannot tolerate frost and prefers temperatures above 15°C.
Soil Requirements
The plant grows best in well-draining soils with a pH range between 6.0 and 7.5. It can also tolerate salty soils but not waterlogged ones. The soil should be rich in organic matter, with a good balance of nitrogen, phosphorus, and potassium.
Cultivation methods
Vigna unguiculata(L.) Walp. ssp. unguiculata is a warm-season crop that thrives in well-drained soil with a pH range of 5.5-6.5. These plants prefer a sunny location and need to be protected from frost since they are sensitive to cold weather. This plant species can be cultivated in either rows or hills. When planting in rows, it is recommended to plant each seed about 1 inch deep at a spacing of 4-6 inches apart.
Watering needs
Vigna unguiculata(L.) Walp. ssp. unguiculata needs to be watered regularly to maintain moisture in the soil. However, care should be taken to avoid overwatering as this can lead to root rot. Watering should be done in the morning or evening to reduce water evaporation rates and to allow sufficient time for the water to be absorbed into the soil.
Fertilization
It is essential to fertilize Vigna unguiculata(L.) Walp. ssp. unguiculata as they are heavy feeders and require a lot of nutrients to grow optimally. Nitrogen, phosphorus, and potassium are the primary nutrients required by the plants. A balanced fertilizer can be applied per manufacturer's instructions at a rate of 500-1000 lbs per acre before planting. Additionally, side-dressing with nitrogen can be done two to three times during the growing season to ensure continued growth and development.
Pruning
Although not necessary, pruning can be done to redirect the plant's energy towards producing more pods. Pruning should be done when the plant is about six inches tall, and it involves removing the top 3-4 inches of the plant to encourage lateral branching. Pruning should be done using a sharp and sterile tool to prevent the spread of disease.
Propagation of Vigna unguiculata (L.) Walp. ssp. unguiculata
Vigna unguiculata (L.) Walp. ssp. unguiculata, commonly known as cowpea, is a popular legume crop grown in many parts of the world for its edible beans and leaves. Propagation of the plant can be done through various methods, including:
Seed propagation
The most common method of propagating Vigna unguiculata (L.) Walp. ssp. unguiculata is through seeds. The seeds should be carefully selected from mature and healthy mother plants. They are sown in well-prepared planting beds or containers about 3-5 cm deep at a spacing of 30-45 cm between rows and 5-10 cm between plants. The seedlings emerge after about 5-7 days and can be transplanted after 3-4 weeks.
Cuttings propagation
Vigna unguiculata (L.) Walp. ssp. unguiculata can also be propagated vegetatively using stem cuttings. The cuttings should be taken from healthy plants of about 3-6 months old, and the length of the cutting should be about 15-20 cm. The leaves on the lower part of the cutting should be removed, and the cutting should be placed in a rooting hormone before planting. The cuttings are then planted in well-prepared soil, kept moist and protected from direct sunlight until roots develop and new leaves appear.
Layering propagation
Layering is another method of propagating Vigna unguiculata (L.) Walp. ssp. unguiculata. In this method, a low-growing branch is selected and bent to the ground. The lower part of the branch is then scraped slightly and treated with a rooting hormone. The branch is then covered with soil and kept moist until new roots and shoots appear. The new plant can then be separated from the parent plant and transplanted to its final position.
Disease Management
Vigna unguiculata is susceptible to a variety of diseases, including:
- Anthracnose: This fungal disease causes circular or irregularly shaped brown spots on leaves, stems, and pods. To manage anthracnose, remove infected plant material, rotate crops, and apply fungicides as recommended.
- Bacterial blight: This bacterial disease causes water-soaked lesions on leaves and pods that eventually turn brown and become necrotic. To manage bacterial blight, remove infected plant material, rotate crops, and apply copper-based fungicides.
- Mosaic viruses: These viral diseases cause mottled or streaked leaves and stunted growth. To manage mosaic viruses, control aphid populations, remove infected plant material, and plant disease-resistant varieties.
Pest Management
Vigna unguiculata is also susceptible to several pests, including:
- Cowpea curculio: This weevil feeds on flowers and pods, causing distortion and deformation. To manage cowpea curculio, plant early in the season, remove crop residue, and apply insecticides as recommended.
- Thrips: These tiny insects feed on leaves, causing them to turn bronze or silver. To manage thrips, control weed populations, remove infected plant material, and apply insecticides as recommended.
- Pod borers: These larvae bore into pods and destroy developing seeds. To manage pod borers, remove infected plant material, control weed populations, and apply insecticides as recommended.
