Overview
Phaseolus macrorhynchus Harms is a legume species that belongs to the Fabaceae or legume family. It is commonly known as the sword bean or the snake bean. This plant is known for its fast-growing, vining nature that can reach up to 10 meters in length. It produces long, slender pods that contain many seeds that are used for food.
Origin and Distribution
The sword bean is native to the tropics of Central and South America and is thought to have originated in Mexico. It is widely cultivated in tropical regions across the world, including Asia, Africa, and the Pacific Islands. In Southeast Asia, it is commonly grown as a vegetable and is known as 'kacang kuda' in Indonesia, 'buah kentang' in Malaysia, and 'sitaw' in the Philippines.
Uses
The sword bean is a versatile plant with several uses. The seeds of this plant are a good source of protein, vitamins, and minerals and are consumed as a vegetable. They can be eaten fresh, cooked, or roasted. In some countries, the seeds are also ground and used to make a type of flour. The leaves of this plant are also edible and can be used as a source of food for livestock.
In addition to its food uses, the sword bean has several other uses. The plant is used in traditional medicine to treat a variety of ailments, including hypertension, diabetes, and high cholesterol. The plant extracts have also been found to have antifungal and antibacterial properties. The plant is also used as a green manure, as it is able to fix nitrogen and enrich the soil.
General Appearance
The sword bean is a vigorous, fast-growing vine with long, slender stems that can reach up to 10 meters in length. The leaves are trifoliate, meaning that they have three leaflets, and are alternate on the stems. The flowers are small and white and are grouped in clusters. The pods are long and thin, measuring up to 60 cm in length. They are green when young and turn pale brown when mature. The seeds are kidney-shaped and come in a variety of colors, including black, brown, and white.
The sword bean is a hardy plant that can grow in a variety of soils and climates. It is generally grown as an annual, as it does not tolerate frost. The plant requires ample water and sunlight to grow and can benefit from the addition of organic matter to the soil.
Light Requirements
The plant Phaseolus macrorhynchus Harms requires plenty of light to grow and develop properly. It thrives best under full sunlight exposure and requires at least six hours of direct sunlight every day. If the plant is grown indoors, it is essential to place it near a south-facing window to ensure it receives sufficient light. Inadequate light can result in stunted growth, weak stems, and reduced yields.
Temperature Requirements
Phaseolus macrorhynchus Harms thrives in warm environments and cannot withstand frost. The plant grows best in a temperature range between 20°C and 30°C. Temperatures above 35°C can damage the plant and cause wilting. It is essential to protect the plant from extreme temperature variations as they can lead to stunted growth, yield reduction, and even death. During winter, it may be necessary to grow the plant indoors or in a greenhouse to maintain optimal temperatures.
Soil Requirements
The Phaseolus macrorhynchus Harms plant thrives in well-draining soils with a pH of 6.0 to 7.0. The soil should be rich in organic matter, loose, and crumbly, ensuring that roots have no difficulty growing. One can improve fertility by adding compost or well-aged manure to the soil or by using slow-release fertilizer. Ensure that the soil does not become waterlogged as the roots may rot. It is also advisable to mulch the plants to help conserve moisture and prevent weed growth.
Cultivation methods
The plant Phaseolus macrorhynchus Harms is also known as the Scarlet Runner Bean and is commonly grown in gardens for its brightly colored red flowers and tender green pods. It grows optimally in well-draining soil with a pH range of 6.5 to 7.5. Sow the seeds directly into the soil after the last frost passes. Bury the seeds about one inch deep and ensure adequate spacing of at least three feet apart between the plants to allow adequate airflow.
Watering needs
The Scarlet Runner Beans require regular watering to thrive and produce high yields. Water the plants deeply and consistently, ensuring that the soil stays moist but not waterlogged. The best time to water the plants is in the morning to allow the leaves to dry up during the day. During periods of heavy rainfall, reduce watering to prevent the soil from becoming waterlogged.
Fertilization
For optimal growth, Scarlet Runner Bean requires regular feeding throughout the growing season. Apply a nitrogen-rich fertilizer three weeks after planting, when the plants are about four inches tall. During flowering and pod production, apply a high phosphorus fertilizer to enhance the growth and development of the pods and seed production. Avoid using fertilizers that are high in nitrogen during the flowering period since it may lead to excessive foliage growth and reduced pod development.
Pruning
Pruning helps to increase yield and maintain a healthy garden by removing dead or diseased foliage, promoting airflow, and ensuring adequate light penetration to the leaves. Prune the plants when they are four to six inches tall, leaving a minimum of two to four healthy stems per plant. Pinch off the tips of the stems to promote bushier growth. In case the plants develop weak and spindly stems, prune them at the base to allow for the growth of stronger stems.
Propagation of Phaseolus macrorhynchus Harms
Phaseolus macrorhynchus Harms, commonly known as the Sword bean, is a climbing and nitrogen-fixing species that is widely grown for food and medicinal purposes. The plant is propagated both by seeds and vegetative means.
Seed Propagation
Seeds of Phaseolus macrorhynchus Harms can be easily obtained from the plant's mature pods. The seeds are then cleaned, treated with fungicides, and sown in the nursery beds. The optimal time for seed sowing is from mid-May to mid-June when the temperature is higher.
The seeds should be sown at a depth of 3-4 cm and 15-20 cm apart. The nursery beds should be watered regularly and kept moist until the seeds germinate, which usually takes 7-10 days.
Seedlings are then transplanted into individual pots, polybags, or directly in the field when they reach the 4-5 leaf stage. Transplanting should be done during the evening to avoid injury to the seedlings. The seedlings should be spaced at least 1 m apart and supported with stakes or trellis.
Vegetative Propagation
Phaseolus macrorhynchus Harms can also be propagated vegetatively through stem cuttings. The cuttings are obtained from healthy and disease-free mature plants during the rainy season. The cuttings should be 20-25 cm long, have at least three nodes, and should be dipped in rooting hormone before planting.
The cuttings are planted at a depth of 5 cm in well-prepared nursery beds or polybags filled with a well-draining potting mix. The cuttings should be watered regularly and kept moist for the first few weeks until they form roots and new growth. They should be transplanted into the field when they show significant growth, which usually takes 3-4 weeks.
Both seed and vegetative propagation methods are effective for Phaseolus macrorhynchus Harms. However, seed propagation is the most common and convenient method and is preferred over vegetative propagation.
Disease and Pest Management for Phaseolus macrorhynchus Harms
Phaseolus macrorhynchus Harms, also known as the wild bean or large-beaked bean, is a legume species that is commonly grown for food. Like any other plant, it is susceptible to different pests and diseases that can affect its growth and yield. Here are some common diseases and pests that might affect Phaseolus macrorhynchus Harms, and some ways to manage them:
Diseases
Anthracnose: This fungal disease can cause leaf spots, stem cankers, and pod rot, reducing the yield and quality of the crop. To manage anthracnose, remove and destroy infected plant debris, rotate crops, apply fungicide, and provide good air circulation and proper drainage.
Bacterial Blight: This bacterial disease can cause wilting, leaf spots, and pod browning, leading to yield losses. To manage bacterial blight, avoid overhead watering, remove and destroy infected plant debris, apply copper-based fungicide, and rotate crops.
Viruses: Phaseolus macrorhynchus Harms can be infected by different viruses, such as the bean common mosaic virus and the cucumber mosaic virus. These viruses can cause stunted growth, yellowing, and necrosis of leaves, reducing the yield and quality of the crop. To manage viruses, plant resistant varieties, practice good hygiene, and control the insect vectors that can spread the viruses.
Pests
Aphids: These small insects can feed on the sap of the plant, causing yellowing, curling, and distortion of the leaves. To manage aphids, use insecticidal soap or neem oil, introduce natural predators, and remove plant debris where aphids can hide.
Cutworms: These larvae can cut the stems of young plants and seedlings, causing wilting and death. To manage cutworms, apply insecticidal bait around the base of the plants and use physical barriers, such as collars or netting, to prevent the larvae from reaching the plants.
Leafminers: These insects can cause distinctive serpentine mines on the leaves, reducing the photosynthetic capacity of the plant. To manage leafminers, use yellow sticky traps, apply neem oil or spinosad, and remove and destroy infested plant material.
By implementing these disease and pest management strategies, it is possible to maintain healthy Phaseolus macrorhynchus Harms crops and ensure a good yield of high-quality beans.
