General Description
Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. is a type of legume commonly known as yardlong bean or snake bean. It belongs to the Fabaceae plant family and is native to Southeast Asia. The plant's stems are long, thin, and vine-like, and it can grow up to 9 feet tall. The plant produces clusters of long, slender pods that can reach up to 3 feet in length. The pods contain small, tender seeds that are edible when cooked.
Common Names
The yardlong bean goes by many names around the world, including asparagus bean, Chinese long bean, and dau gok in Asia. In Africa, it is known as nitta, while in the Caribbean, it is called bodi or bodhi.
Uses
The yardlong bean is a popular vegetable in Asian cuisine, particularly in Chinese, Thai, and Vietnamese dishes. The tender pods can be stir-fried, pickled, or used in soups and stews. The plant is also used in traditional medicine to treat various ailments, including high blood pressure and diabetes. The plant has an extensive root system that helps to improve soil fertility, making it a useful crop in sustainable agriculture practices.
General Appearance
The yardlong bean plant has long, thin stems that climb and wrap around other plants or supports. The leaves are bright green, oval-shaped, and grow in pairs along the stem. The pods are slender, cylindrical, and can grow up to 3 feet long. They are usually harvested when young and tender, before the seeds inside fully develop. The pods' color varies depending on the variety and can range from light green to dark purple.
Light Requirements
Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. requires full sunlight exposure to thrive. It must be grown in an area that receives at least 6-8 hours of direct sunlight every day. Partial shade may also be tolerated, but it will reduce the growth rate and yield of the plant.
Temperature Requirements
The plant grows optimally in temperatures ranging from 23-35°C (73-95°F). Lower temperatures can cause damage to the plant, while higher temperatures can lead to wilting and reduced growth. The plant cannot tolerate frost, so it is recommended to be grown in tropical and subtropical regions that have warm climates.
Soil Requirements
Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. thrives in well-drained, nutrient-rich soils. The ideal pH range for the plant is between 6.0-6.5. It can tolerate a wide range of soil types, from sandy to clayey. However, the soil must be loose and friable to allow the roots to penetrate easily. The plant requires regular watering, but overwatering can cause root rot and adversely affect growth.
Cultivation Methods
Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc., also known as yardlong bean or snake bean, is a tropical vining plant that requires warm weather and full sunlight. It is best grown in well-draining soil that is rich in organic matter. The seeds must be sowed at a depth of 1-2 inches, with a distance of 4-6 inches apart. The rows must be spaced 2-3 feet apart.Watering Needs
Yardlong bean plants require consistent moisture, especially during the germination and flowering stages. The soil must be kept moist but not waterlogged. Over-watering can lead to fungal diseases and root rot. The frequency of watering may depend on the climate and soil type, but a general guideline is to water deeply once a week or as needed.Fertilization
To ensure optimal growth and yield, yardlong beans require regular fertilization. Nitrogen-rich fertilizers such as fish emulsion or compost can be added every 2-3 weeks. Additionally, a phosphorus-rich fertilizer can be added during the flowering and fruiting stages. It is important to avoid over-fertilization, as this can lead to excessive foliage growth and reduced yield.Pruning
Pruning is not necessary for yardlong bean plants. However, it is recommended to remove any diseased, damaged or dead leaves or stems. This can promote plant health and prevent the spread of diseases. Moreover, removing excess foliage can promote air circulation and allow sunlight to reach the lower leaves, which can lead to a higher yield.Propagation of Vigna unguiculata subsp. sesquipedalis
Commonly known as the yard-long bean or Chinese long bean, Vigna unguiculata subsp. sesquipedalis is propagated through seeds, cuttings, and grafting.
Seed Propagation
Seeds are the most common method of propagation for Vigna unguiculata subsp. sesquipedalis. The seeds can be directly sown in the garden bed or raised in nurseries. Seeds collected from mature pods should be preferred for propagation to ensure better germination.
The seeds should be soaked in water for 12 to 24 hours before sowing. This helps to soften the seed coat, resulting in quicker germination. The seeds should be sown 3-5 cm deep in well-drained soils, and the seedlings should emerge within 7-10 days.
Cutting Propagation
Vigna unguiculata subsp. sesquipedalis can also be propagated through cuttings. The cuttings should be 30-40 cm long and taken from healthy, mature plants. The cuttings should be taken during the dormant season and planted in well-fertilized soil. In 3-4 weeks, the cuttings will root and start growing new shoots.
Grafting Method
Grafting is another propagation method used for Vigna unguiculata subsp. sesquipedalis. The upper portion of the plant to be propagated (scion) is grafted onto the lower portion of another healthy plant related to Vigna unguiculata (rootstock). Grafting allows for a combination of desirable traits to be obtained in the plant. The success rate of grafting can be increased with the use of appropriate equipment, handling techniques, and rooting hormones.
The propagation method used for Vigna unguiculata subsp. sesquipedalis will depend on the available resources, the purpose of propagation, and the desired outcomes.
Disease Management
Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. is susceptible to various diseases that can cause damage to the plant and reduce its yield. The following are the most common diseases that can affect the plant:
1. Anthracnose: This disease causes dark brown or black lesions on the leaves, veins, stems, and pods. The lesions may be circular or elongated, and they may have a yellow halo around them. To manage anthracnose, it is essential to remove and destroy all infected plant parts, especially before the flowering period. Using disease-resistant varieties and practicing crop rotation can also help prevent this disease.
2. Mosaic Virus: This disease causes yellow or green mottling on the leaves of the plant. The infected plants may also have stunted growth and reduced yields. To manage mosaic virus, remove and destroy all infected plants immediately and control aphids, which are known to spread the virus. Planting virus-free seeds and avoiding the use of contaminated tools can also help prevent this disease.
3. Powdery Mildew: Powdery mildew is a fungal disease that causes white or gray powdery patches on the leaves. The infected leaves may eventually become yellow and fall off. To control powdery mildew, remove all infected plant parts immediately and avoid watering the leaves. Pruning the plants to improve air circulation and using fungicides can also help prevent the disease.
Pest Management
In addition to diseases, Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. may also be affected by various pests. The following are some of the most common pests that may affect the plant:
1. Aphids: Aphids are small, sap-sucking insects that can cause stunted growth, distorted leaves, and reduced yields. To control aphids, spray the plants with a strong jet of water to dislodge the insects. Using insecticidal soap or neem oil can also help manage aphids.
2. Bean Beetles: Bean beetles are small, brown bugs that feed on the leaves, flowers, and pods of the plant. They can cause significant damage to the plant and reduce its yield. To manage bean beetles, remove and destroy all infected plant parts immediately and control the weeds around the plants. Using insecticidal soap, neem oil, or pyrethrin can also help prevent this pest.
3. Cutworms: Cutworms are caterpillars that feed on the stems and leaves of the plant and can cause significant damage. To manage cutworms, till the soil thoroughly before planting and remove any weeds or debris that may serve as host plants for the caterpillars. Using Bacillus thuringiensis (Bt) or spinosad can also help prevent cutworms.
By practicing good cultural practices, such as regular watering, fertilizing, and weed control, as well as implementing the above disease and pest management strategies, you can help ensure a healthy and productive Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc. crop.
