Overview
Dolichos oliveri Schweinf. is a species of flowering plant in the family Fabaceae. It is native to tropical Africa, specifically in countries such as Cameroon, Gabon, Congo, and the Democratic Republic of the Congo. It is also cultivated and naturalized in other parts of Africa.
Common Names
This plant is commonly known as Oliver's bean, wild bean, and Congolese bean. In some regions, it is also referred to as a "poor man's bean" due to its importance as a cheap and accessible source of protein.
Uses
Dolichos oliveri Schweinf. has been traditionally used for various purposes in African communities. Its seeds are edible and are often boiled or roasted and consumed as a protein-rich food source. The leaves are also consumed as a vegetable and have been used in traditional medicine to treat various ailments, including constipation and fever.
In addition to its nutritional and medicinal value, Dolichos oliveri Schweinf. is also used for soil improvement. The plant has nitrogen-fixing properties, which means it can improve the quality of soil by adding nitrogen to it. As a result, it is often used as a cover crop to improve soil fertility and prevent soil erosion.
Appearance
Dolichos oliveri Schweinf. is a climbing plant that can grow up to 4 meters in length. It has large, oval-shaped leaves that are dark green in color and can reach up to 25 cm in length. The flowers are creamy white and are produced in clusters. The plant produces pods that are up to 10 cm in length and contain several kidney-shaped seeds that are brownish-black in color.
Light Conditions
The plant Dolichos oliveri Schweinf. requires moderate to full sunlight in order to grow and thrive. It is recommended to place the plant in a location where it can receive at least six hours of sunlight per day. However, the plant should be protected from intense sunlight during the hottest part of the day to prevent damage to the leaves and flowers.
Temperature Requirements
The plant Dolichos oliveri Schweinf. prefers warm temperatures and is not frost tolerant. It grows best in areas with temperatures ranging between 20°C to 30°C (68°F to 86°F). Temperatures below 10°C (50°F) can cause damage to the plant and hinder its growth. It is important to protect the plant from extreme temperature changes and ensure that it is not exposed to cold drafts or sudden drops in temperature.
Soil Requirements
The soil requirements for Dolichos oliveri Schweinf. are well-draining and fertile soil. The plant grows best in soil that is rich in organic matter and has a pH level between 6.0 and 7.5. Adding compost or other organic matter to the soil can improve soil fertility by providing essential nutrients to the plant. It is important to avoid waterlogged soil as it can cause root rot and damage the plant.
Cultivation Methods for Dolichos oliveri Schweinf.
Dolichos oliveri Schweinf. is a climbing plant that requires a support structure to grow upwards. The ideal support for this plant is a trellis or a frame made of bamboo, wood, or metal. Ensure that the support structure is firmly fixed in the ground to prevent collapsing under the weight of the plant.
The plant grows well in well-draining soil that is rich in organic matter. A soil pH of 6.5 to 7.5 is optimal for Dolichos oliveri Schweinf. Prepare the soil by loosening it to a depth of 30 cm and removing any rocks or debris.
Watering Needs for Dolichos oliveri Schweinf.
Water Dolichos oliveri Schweinf. regularly and consistently to keep the soil moist but not waterlogged. Water the plant early in the morning or late in the evening to prevent the leaves from scorching in the hot sun. Avoid watering the leaves and flowers directly as this can promote the growth of fungal diseases.
During periods of drought or high temperatures, increase the frequency of watering to prevent the plant from drying out. In contrast, reduce watering during the rainy season to prevent waterlogging and root rot.
Fertilization for Dolichos oliveri Schweinf.
Fertilize Dolichos oliveri Schweinf. with a balanced fertilizer that is high in nitrogen and phosphorus but low in potassium. Use a slow-release fertilizer during the growing season to provide a steady supply of nutrients. Apply the fertilizer according to the manufacturer's instructions and water thoroughly afterwards to prevent burning the plant.
Alternatively, use organic fertilizers such as compost, manure, or bone meal to provide nutrients to the plant. Organic fertilizers release nutrients slowly and improve the soil structure, water-holding capacity and beneficial microorganisms that contribute to plant growth.
Pruning for Dolichos oliveri Schweinf.
Prune Dolichos oliveri Schweinf. to control its size and shape, to remove damaged or diseased branches, and to promote flowering. Prune the plant in early spring before new growth begins. Use sharp and sterile pruning shears to prevent damaging the plant.
To remove unwanted branches, cut them as close to the base as possible, at a 45-degree angle. To promote branching and bushiness, pinch the tips of young shoots when they reach the desired length. Remove any crossing or rubbing branches to prevent them from becoming entangled and promoting fungal diseases.
Propagation Methods for Dolichos oliveri Schweinf.
Dolichos oliveri Schweinf. is propagated through seeds or vegetative cuttings. However, the success rate of vegetative propagation is very low, and seed propagation is the most preferred method.
Seed Propagation
Seeds of Dolichos oliveri Schweinf. should be sown in seedbeds or polybags during the rainy season. Before sowing, the seeds should be soaked in water for 24 hours to improve the germination rate.
The seedbeds should have a mixture of sand, soil, and organic manure in the ratio of 1:1:1. The seeds should be sown in rows, and the distance between two rows should be around 20 cm. Light watering should be done immediately after sowing.
The seedbeds should be kept moist by light, frequent watering. Germination of seeds starts within 10 to 15 days of sowing. After germination, the seedlings should be transplanted to pots or polybags. The seedlings should be provided with partial shade until they are established.
Vegetative Propagation
Vegetative propagation of Dolichos oliveri Schweinf. can be done through stem cuttings or layering. However, the success rate of vegetative propagation is very low, and it is not a preferred method.
Stem cuttings should be taken from young, healthy branches during the rainy season. The cuttings should be around 15 cm long and should have at least two or three nodes. The cuttings should be treated with rooting hormone and placed in a rooting medium. Rooting can take up to two months, and after rooting, the cuttings should be transplanted to pots or polybags.
Layering is another method of vegetative propagation. In this method, a portion of the stem is bent to the ground and covered with soil. The portion of the stem covered with soil will develop roots, and after rooting, it can be separated from the main plant and transplanted to pots or polybags.
Disease Management
Dolichos oliveri Schweinf., commonly known as Oliver's bean, is susceptible to various diseases that can damage the plant. Here are some common diseases that might affect the plant:
- Anthracnose – This fungal disease causes wilting, yellowing, and spotting of foliage. It can also affect the blooms and pods. To manage this disease, remove the infected plant parts and spray with a fungicide.
- Rust – Rust disease causes small yellow spots on leaves that later turn into brown or black lesions. It can also affect the seedlings. To manage rust, remove infected leaves, and ensure that the plant is well-ventilated.
- Mosaic virus – This viral disease causes mottled leaves and stunted growth. Infected plants may also show distorted leaves and pods. There is no cure for mosaic virus, so it is important to remove and destroy infected plants to prevent the spread of the disease.
Pest Management
Oliver's bean is also prone to insect infestations that can cause significant damage to the plant. Here are some common pests that might affect the plant:
- Aphids – Aphids suck the sap from the plant, causing curling and yellowing of foliage. To manage aphids, you can spray the plant with insecticidal soap or neem oil.
- Cutworms – Cutworms are nocturnal caterpillars that can cut through the stem of young plants, causing them to wilt and die. To manage cutworms, handpick them off the plants or use a biological control such as Bacillus thuringiensis var. kurstaki.
- Mites – Mites can cause stippling, yellowing, and wilting of foliage. To manage mites, you can spray the plant with a miticide or use a biological control such as ladybugs.
Regular monitoring of the plant can help in the early detection of diseases and pests. It is also important to maintain proper garden hygiene and provide the plant with appropriate cultural conditions to help prevent disease and pest infestation.
