Origin
Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine, commonly known as cowpea or black-eyed pea, is a subspecies of the Vigna unguiculata species which is native to West Africa, but has been cultivated throughout the world for thousands of years. It was introduced to the Americas during the slave trade.
Common Names
Cowpea is known by several other common names, including southern pea, crowder pea, and field pea. Its black and white pattern on the seed has led to its other name, black-eyed pea.
Uses
The cowpea is a versatile crop that is primarily grown for its edible seeds. These seeds are high in protein, dietary fiber, and various essential vitamins and minerals. They can be cooked in a variety of ways and are commonly used in soups, stews, and salads. Cowpeas are also used in animal feed and as a cover crop to prevent soil erosion. Additionally, the plant is beneficial as a nitrogen fixer, meaning it helps replenish nitrogen in the soil.
General Appearance
Cowpea is a warm-season annual plant that can grow up to six feet tall. It has long, slender leaves that are typically green in color. The plant produces small, white to light pink flowers that develop into pods. Inside these pods are oval-shaped seeds with a characteristic black and white pattern. Cowpea seeds can be eaten fresh or dried, and are often referred to as legumes.
Light Requirements
Vigna unguiculata subsp. cylindrica typically requires full sun exposure to grow properly. They can tolerate some shade but the plant may not produce as much bounty in such conditions. If grown indoors, grow lights can be used to provide the necessary amount of light.
Temperature Range
Vigna unguiculata subsp. cylindrica is a warm season crop and is well-suited for tropical and subtropical regions. The plant thrives in temperatures ranging from 77-95°F during the day and 68-77°F at night. Temperatures below 60°F can significantly slow down growth or even kill the plant.
Soil Requirements
Vigna unguiculata subsp. cylindrica grows best in well-drained soil that holds moisture and nutrients. The plant prefers slightly acidic to neutral soil with a pH range of 6.0-7.5. The soil should be rich in organic matter and have good water retention. Sandy or clay soils should be amended with organic matter prior to planting to improve water drainage and aeration.
Cultivation Methods
Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine, also known as the yard-long bean or cowpea, is a warm-season legume plant that prefers full sunlight and grows best in well-drained, sandy loam soil. The seeds should be sown directly into the ground after the last frost, spaced six inches apart and one inch deep. When the seedlings attain a height of 4 to 6 inches, thin them to a distance of 12 inches between the plants.
Watering Needs
The yard-long bean plant requires moderate to frequent watering, particularly during the growing season. It is important to keep the soil evenly moist but not waterlogged to prevent the onset of root rot. The plant also benefits from mulching to prevent moisture from evaporating too quickly.
Fertilization
Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine is a heavy feeder that requires fertile soil to produce a bountiful harvest. An application of compost to the soil before planting or a balanced fertilizer once a month during the growing season can help ensure the plant's nutrient needs are met.
Pruning
Yard-long bean plants benefit from pruning to increase their yield and reduce the chances of disease. Pinch off the growing tips of the plants when they reach a height of 12 inches to encourage branching, which leads to the development of more pods. Remove any yellow or diseased leaves as soon as they appear and any dead or senescent plant material before it can invite pests or pathogens.
Propagation of Vigna unguiculata (L.) Walp. subsp. Cylindrica (L.) Eseltine
Vigna unguiculata (L.) Walp. subsp. Cylindrica (L.) Eseltine, commonly known as yardlong bean or asparagus bean, can be propagated through various methods, including:
Seed Propagation
The easiest and most common way to propagate yardlong beans is through seeds. Collect mature pods from the plants that exhibit desirable characteristics. Choose the biggest and healthiest seeds for planting. Seeds should be sown during the warm seasons, with a temperature range of 20 to 25°C. Plant the seeds about 2-3 cm in depth and approximately 10-15 cm apart. It takes about 3-5 days to germinate.
Cuttings Propagation
Another method of propagating yardlong beans is through hardwood cuttings. Cut a 15 cm hardwood with three leaves attached just at the base and dip it in rooting hormone powder, then plant the cutting in soil. Keep the soil moist and place it in a shaded area to prevent the leaves from wilting. After a few days, the cutting will develop roots and can be transplanted to the garden.
Tissue Culture Propagation
For mass production of yardlong beans, tissue culture propagation is recommended. It involves taking a piece of plant tissue and growing it in a laboratory under sterile conditions. The tissue will grow into a new plant which can be transplanted for further growth. Tissue culture helps in producing many uniform plants with desirable characteristics.
Yardlong beans are easy to propagate as it grows vigorously in favourable conditions without much care, and one plant can produce numerous pods of beans.
Disease Management for Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine
Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine, commonly known as cowpea, is susceptible to various diseases that can cause significant damage to the crop and reduce yield. Therefore, disease management is an essential component of cowpea cultivation.
Common Diseases
The following are the most common diseases that affect cowpea:
- Anthracnose
- Bacterial blight
- Cercospora leaf spot
- Fusarium wilt
- Mosaic virus
Management Strategies
Here are some strategies to manage diseases in cowpea:
- Use disease-resistant varieties: Choose cowpea varieties that are resistant or tolerant to diseases prevalent in your area.
- Crop rotation: Rotate cowpea with non-host crops to disrupt the disease cycle and reduce the buildup of pathogens in the soil.
- Sanitation: Remove and destroy infected plant debris and weeds from the field to prevent the spread of diseases.
- Fungicide application: Apply appropriate fungicides to control fungal diseases.
- Bactericide application: Apply bactericides to control bacterial diseases.
- Virus vector control: Control the insect vectors that transmit viral diseases by using insecticides, planting virus-resistant varieties, or using physical barriers.
Pest Management for Vigna unguiculata (L.) Walp. subsp. cylindrica (L.) Eseltine
Cowpea is also susceptible to several pests that can cause significant yield loss. Therefore, effective pest management is essential to maintain crop productivity and quality.
Common Pests
The following are the most common pests that affect cowpea:
- Aphids
- Spider mites
- Thrips
- Cowpea curculio
- Cowpea weevil
Management Strategies
Here are some strategies to manage pests in cowpea:
- Use resistant/tolerant varieties: Choose cowpea varieties that are resistant or tolerant to the prevalent pests in your area.
- Sanitation: Remove and destroy crop debris and weeds that can serve as hosts for pests.
- Biological control: Introduce natural predators or parasites of the pests to the field.
- Chemical control: Apply appropriate insecticides to control pest populations. Avoid overuse of pesticides to prevent environmental pollution and resistance development.
- Physical control: Use physical barriers such as nets to prevent pest infestations.
